Merge pull request #253 from Rafostar/clappersink2

Move away from GtkGLArea

lib/gst/meson.build

@@ -1 +1,7 @@
-subdir('clapper')
+if get_option('lib')
+  subdir('clapper')
+endif
+
+if not get_option('gst-plugin').disabled()
+  subdir('plugin')
+endif

lib/gst/plugin/gstclapperimporter.c

@@ -0,0 +1,439 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstclapperimporter.h"
+#include "gstgtkutils.h"
+
+#define GST_CAT_DEFAULT gst_clapper_importer_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+#define parent_class gst_clapper_importer_parent_class
+G_DEFINE_TYPE (GstClapperImporter, gst_clapper_importer, GST_TYPE_OBJECT);
+
+typedef struct
+{
+  GdkTexture *texture;
+  GstVideoOverlayRectangle *rectangle;
+
+  gint x, y;
+  guint width, height;
+
+  gint index;
+  gatomicrefcount ref_count;
+} GstClapperGdkOverlay;
+
+static GstClapperGdkOverlay *
+gst_clapper_gdk_overlay_new (GdkTexture *texture, GstVideoOverlayRectangle *rectangle,
+    gint x, gint y, guint width, guint height, guint index)
+{
+  GstClapperGdkOverlay *overlay = g_slice_new (GstClapperGdkOverlay);
+
+  overlay->texture = g_object_ref (texture);
+  overlay->rectangle = gst_video_overlay_rectangle_ref (rectangle);
+  overlay->x = x;
+  overlay->y = y;
+  overlay->width = width;
+  overlay->height = height;
+  overlay->index = index;
+
+  g_atomic_ref_count_init (&overlay->ref_count);
+
+  return overlay;
+}
+
+static GstClapperGdkOverlay *
+gst_clapper_gdk_overlay_ref (GstClapperGdkOverlay *overlay)
+{
+  g_atomic_ref_count_inc (&overlay->ref_count);
+
+  return overlay;
+}
+
+static void
+gst_clapper_gdk_overlay_unref (GstClapperGdkOverlay *overlay)
+{
+  if (g_atomic_ref_count_dec (&overlay->ref_count)) {
+    GST_TRACE ("Freeing overlay: %" GST_PTR_FORMAT, overlay);
+
+    g_object_unref (overlay->texture);
+    gst_video_overlay_rectangle_unref (overlay->rectangle);
+    g_slice_free (GstClapperGdkOverlay, overlay);
+  }
+}
+
+static GstBufferPool *
+_default_create_pool (GstClapperImporter *self, GstStructure **config)
+{
+  GST_FIXME_OBJECT (self, "Need to create buffer pool");
+
+  return NULL;
+}
+
+static GdkTexture *
+_default_generate_texture (GstClapperImporter *self,
+    GstBuffer *buffer, GstVideoInfo *v_info)
+{
+  GST_FIXME_OBJECT (self, "GdkTexture generation not implemented");
+
+  return NULL;
+}
+
+static void
+gst_clapper_importer_init (GstClapperImporter *self)
+{
+  gst_video_info_init (&self->pending_v_info);
+  gst_video_info_init (&self->v_info);
+
+  self->pending_overlays = g_ptr_array_new_with_free_func (
+      (GDestroyNotify) gst_clapper_gdk_overlay_unref);
+  self->overlays = g_ptr_array_new_with_free_func (
+      (GDestroyNotify) gst_clapper_gdk_overlay_unref);
+
+  gdk_rgba_parse (&self->bg, "black");
+}
+
+static void
+gst_clapper_importer_finalize (GObject *object)
+{
+  GstClapperImporter *self = GST_CLAPPER_IMPORTER_CAST (object);
+
+  GST_TRACE ("Finalize");
+
+  gst_clear_buffer (&self->pending_buffer);
+  gst_clear_buffer (&self->buffer);
+
+  g_ptr_array_unref (self->pending_overlays);
+  g_ptr_array_unref (self->overlays);
+
+  g_clear_object (&self->texture);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
+}
+
+static void
+gst_clapper_importer_class_init (GstClapperImporterClass *klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+  GstClapperImporterClass *importer_class = (GstClapperImporterClass *) klass;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperimporter", 0,
+      "Clapper Importer");
+
+  gobject_class->finalize = gst_clapper_importer_finalize;
+
+  importer_class->create_pool = _default_create_pool;
+  importer_class->generate_texture = _default_generate_texture;
+}
+
+static GstClapperGdkOverlay *
+_get_cached_overlay (GPtrArray *overlays, GstVideoOverlayRectangle *rectangle)
+{
+  guint i;
+
+  for (i = 0; i < overlays->len; i++) {
+    GstClapperGdkOverlay *overlay = g_ptr_array_index (overlays, i);
+
+    if (overlay->rectangle == rectangle)
+      return overlay;
+  }
+
+  return NULL;
+}
+
+static gint
+_sort_overlays_cb (gconstpointer a, gconstpointer b)
+{
+  GstClapperGdkOverlay *overlay_a, *overlay_b;
+
+  overlay_a = *((GstClapperGdkOverlay **) a);
+  overlay_b = *((GstClapperGdkOverlay **) b);
+
+  return (overlay_a->index - overlay_b->index);
+}
+
+/*
+ * Prepares overlays to show with the next rendered buffer.
+ *
+ * In order for overlays caching to work correctly, this should be called for
+ * every received buffer (even if its going to be disgarded), also must be
+ * called together with pending buffer replacement within a single importer
+ * locking, to make sure prepared overlays always match the pending buffer.
+ */
+static void
+gst_clapper_importer_prepare_overlays_locked (GstClapperImporter *self)
+{
+  GstVideoOverlayCompositionMeta *comp_meta;
+  guint num_overlays, i;
+
+  if (G_UNLIKELY (!self->pending_buffer)
+      || !(comp_meta = gst_buffer_get_video_overlay_composition_meta (self->pending_buffer))) {
+    guint n_pending = self->pending_overlays->len;
+
+    /* Remove all cached overlays if new buffer does not have any */
+    if (n_pending > 0) {
+      GST_TRACE ("No overlays in buffer, removing all cached ones");
+      g_ptr_array_remove_range (self->pending_overlays, 0, n_pending);
+    }
+
+    return;
+  }
+
+  GST_LOG_OBJECT (self, "Preparing overlays...");
+
+  /* Mark all old overlays as unused by giving them negative index */
+  for (i = 0; i < self->pending_overlays->len; i++) {
+    GstClapperGdkOverlay *overlay = g_ptr_array_index (self->pending_overlays, i);
+    overlay->index = -1;
+  }
+
+  num_overlays = gst_video_overlay_composition_n_rectangles (comp_meta->overlay);
+
+  for (i = 0; i < num_overlays; i++) {
+    GdkTexture *texture;
+    GstBuffer *comp_buffer;
+    GstVideoFrame comp_frame;
+    GstVideoMeta *v_meta;
+    GstVideoInfo v_info;
+    GstVideoOverlayRectangle *rectangle;
+    GstClapperGdkOverlay *overlay;
+    GstVideoOverlayFormatFlags flags, alpha_flags = 0;
+    gint comp_x, comp_y;
+    guint comp_width, comp_height;
+
+    rectangle = gst_video_overlay_composition_get_rectangle (comp_meta->overlay, i);
+
+    if ((overlay = _get_cached_overlay (self->pending_overlays, rectangle))) {
+      overlay->index = i;
+
+      GST_TRACE ("Reusing cached overlay: %" GST_PTR_FORMAT, overlay);
+      continue;
+    }
+
+    if (G_UNLIKELY (!gst_video_overlay_rectangle_get_render_rectangle (rectangle,
+        &comp_x, &comp_y, &comp_width, &comp_height))) {
+      GST_WARNING ("Invalid overlay rectangle dimensions: %" GST_PTR_FORMAT, rectangle);
+      continue;
+    }
+
+    flags = gst_video_overlay_rectangle_get_flags (rectangle);
+
+    if (flags & GST_VIDEO_OVERLAY_FORMAT_FLAG_PREMULTIPLIED_ALPHA)
+      alpha_flags |= GST_VIDEO_OVERLAY_FORMAT_FLAG_PREMULTIPLIED_ALPHA;
+
+    comp_buffer = gst_video_overlay_rectangle_get_pixels_unscaled_argb (rectangle, alpha_flags);
+
+    /* Update overlay video info from video meta */
+    if ((v_meta = gst_buffer_get_video_meta (comp_buffer))) {
+      gst_video_info_set_format (&v_info, v_meta->format, v_meta->width, v_meta->height);
+      v_info.stride[0] = v_meta->stride[0];
+    }
+
+    if (G_UNLIKELY (!gst_video_frame_map (&comp_frame, &v_info, comp_buffer, GST_MAP_READ)))
+      return;
+
+    if ((texture = gst_video_frame_into_gdk_texture (&comp_frame))) {
+      overlay = gst_clapper_gdk_overlay_new (texture, rectangle, comp_x, comp_y,
+          comp_width, comp_height, i);
+      g_object_unref (texture);
+
+      GST_TRACE_OBJECT (self, "Created overlay: %"
+          GST_PTR_FORMAT ", x: %i, y: %i, width: %u, height: %u",
+          overlay, overlay->x, overlay->y, overlay->width, overlay->height);
+
+      g_ptr_array_insert (self->pending_overlays, i, overlay);
+    }
+
+    gst_video_frame_unmap (&comp_frame);
+  }
+
+  /* Remove all overlays that are not going to be used */
+  for (i = self->pending_overlays->len; i > 0; i--) {
+    GstClapperGdkOverlay *overlay = g_ptr_array_index (self->pending_overlays, i - 1);
+
+    if (overlay->index < 0) {
+      GST_TRACE ("Removing unused cached overlay: %" GST_PTR_FORMAT, overlay);
+      g_ptr_array_remove (self->pending_overlays, overlay);
+    }
+  }
+
+  /* Sort remaining overlays */
+  if (self->pending_overlays->len > 1) {
+    GST_LOG_OBJECT (self, "Sorting overlays");
+    g_ptr_array_sort (self->pending_overlays, (GCompareFunc) _sort_overlays_cb);
+  }
+
+  if (G_UNLIKELY (num_overlays != self->pending_overlays->len)) {
+    GST_WARNING_OBJECT (self, "Some overlays could not be prepared, %u != %u",
+        num_overlays, self->pending_overlays->len);
+  }
+
+  GST_LOG_OBJECT (self, "Prepared overlays: %u", self->pending_overlays->len);
+}
+
+gboolean
+gst_clapper_importer_prepare (GstClapperImporter *self)
+{
+  GstClapperImporterClass *importer_class = GST_CLAPPER_IMPORTER_GET_CLASS (self);
+
+  if (importer_class->prepare) {
+    if (!importer_class->prepare (self))
+      return FALSE;
+  }
+
+  GST_DEBUG_OBJECT (self, "Importer prepared");
+
+  return TRUE;
+}
+
+void
+gst_clapper_importer_share_data (GstClapperImporter *self, GstClapperImporter *dest)
+{
+  GstClapperImporterClass *importer_class = GST_CLAPPER_IMPORTER_GET_CLASS (self);
+
+  if (importer_class->share_data)
+    importer_class->share_data (self, dest);
+}
+
+void
+gst_clapper_importer_set_caps (GstClapperImporter *self, GstCaps *caps)
+{
+  GstClapperImporterClass *importer_class = GST_CLAPPER_IMPORTER_GET_CLASS (self);
+
+  GST_OBJECT_LOCK (self);
+  self->has_pending_v_info = gst_video_info_from_caps (&self->pending_v_info, caps);
+  GST_OBJECT_UNLOCK (self);
+
+  if (importer_class->set_caps)
+    importer_class->set_caps (self, caps);
+}
+
+void
+gst_clapper_importer_set_buffer (GstClapperImporter *self, GstBuffer *buffer)
+{
+  /* Both overlays and pending buffer must be
+   * set within a single importer locking */
+  GST_OBJECT_LOCK (self);
+
+  gst_buffer_replace (&self->pending_buffer, buffer);
+  gst_clapper_importer_prepare_overlays_locked (self);
+
+  GST_OBJECT_UNLOCK (self);
+}
+
+GstBufferPool *
+gst_clapper_importer_create_pool (GstClapperImporter *self, GstStructure **config)
+{
+  GstClapperImporterClass *importer_class = GST_CLAPPER_IMPORTER_GET_CLASS (self);
+
+  return importer_class->create_pool (self, config);
+}
+
+void
+gst_clapper_importer_add_allocation_metas (GstClapperImporter *self, GstQuery *query)
+{
+  GstClapperImporterClass *importer_class = GST_CLAPPER_IMPORTER_GET_CLASS (self);
+
+  if (importer_class->add_allocation_metas)
+    importer_class->add_allocation_metas (self, query);
+}
+
+gboolean
+gst_clapper_importer_handle_context_query (GstClapperImporter *self,
+    GstBaseSink *bsink, GstQuery *query)
+{
+  GstClapperImporterClass *importer_class = GST_CLAPPER_IMPORTER_GET_CLASS (self);
+
+  if (!importer_class->handle_context_query)
+    return FALSE;
+
+  return importer_class->handle_context_query (self, bsink, query);
+}
+
+void
+gst_clapper_importer_snapshot (GstClapperImporter *self, GdkSnapshot *snapshot,
+    gdouble width, gdouble height, gfloat scale_x, gfloat scale_y)
+{
+  guint i;
+  gboolean buffer_changed;
+
+  /* Collect all data that we need to snapshot pending buffer,
+   * lock ourselves to make sure everything matches */
+  GST_OBJECT_LOCK (self);
+
+  buffer_changed = gst_buffer_replace (&self->buffer, self->pending_buffer);
+
+  /* Only replace v_info when buffer changed, this way
+   * we still use old (correct) v_info when resizing */
+  if (buffer_changed && self->has_pending_v_info) {
+    self->v_info = self->pending_v_info;
+    self->has_pending_v_info = FALSE;
+  }
+
+  /* Ref overlays associated with current buffer */
+  for (i = 0; i < self->pending_overlays->len; i++) {
+    GstClapperGdkOverlay *overlay = g_ptr_array_index (self->pending_overlays, i);
+
+    g_ptr_array_insert (self->overlays, i, gst_clapper_gdk_overlay_ref (overlay));
+  }
+
+  GST_OBJECT_UNLOCK (self);
+
+  /* Draw black BG when no buffer or imported format has alpha */
+  if (!self->buffer || GST_VIDEO_INFO_HAS_ALPHA (&self->v_info))
+    gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, 0, width, height));
+
+  if (self->buffer) {
+    if (buffer_changed || !self->texture) {
+      GstClapperImporterClass *importer_class = GST_CLAPPER_IMPORTER_GET_CLASS (self);
+
+      GST_TRACE_OBJECT (self, "Importing %" GST_PTR_FORMAT, self->buffer);
+
+      g_clear_object (&self->texture);
+      self->texture = importer_class->generate_texture (self, self->buffer, &self->v_info);
+    } else {
+      GST_TRACE_OBJECT (self, "Reusing texture from %" GST_PTR_FORMAT, self->buffer);
+    }
+
+    if (G_LIKELY (self->texture)) {
+      gtk_snapshot_append_texture (snapshot, self->texture, &GRAPHENE_RECT_INIT (0, 0, width, height));
+
+      for (i = 0; i < self->overlays->len; i++) {
+        GstClapperGdkOverlay *overlay = g_ptr_array_index (self->overlays, i);
+
+        gtk_snapshot_append_texture (snapshot, overlay->texture,
+            &GRAPHENE_RECT_INIT (overlay->x * scale_x, overlay->y * scale_y,
+                overlay->width * scale_x, overlay->height * scale_y));
+      }
+    } else {
+      GST_ERROR_OBJECT (self, "Failed import of %" GST_PTR_FORMAT, self->buffer);
+
+      /* Draw black instead of texture on failure if not drawn already */
+      if (!GST_VIDEO_INFO_HAS_ALPHA (&self->v_info))
+        gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, 0, width, height));
+    }
+  }
+
+  /* Unref all used overlays */
+  if (self->overlays->len > 0)
+    g_ptr_array_remove_range (self->overlays, 0, self->overlays->len);
+}

lib/gst/plugin/gstclapperimporter.h

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+#include <gtk/gtk.h>
+#include <gst/gst.h>
+#include <gst/video/video.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_IMPORTER               (gst_clapper_importer_get_type())
+#define GST_IS_CLAPPER_IMPORTER(obj)            (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_CLAPPER_IMPORTER))
+#define GST_IS_CLAPPER_IMPORTER_CLASS(klass)    (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_CLAPPER_IMPORTER))
+#define GST_CLAPPER_IMPORTER_GET_CLASS(obj)     (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_CLAPPER_IMPORTER, GstClapperImporterClass))
+#define GST_CLAPPER_IMPORTER(obj)               (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_CLAPPER_IMPORTER, GstClapperImporter))
+#define GST_CLAPPER_IMPORTER_CLASS(klass)       (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_CLAPPER_IMPORTER, GstClapperImporterClass))
+#define GST_CLAPPER_IMPORTER_CAST(obj)          ((GstClapperImporter *)(obj))
+
+#define GST_CLAPPER_IMPORTER_DEFINE(camel,lower,type)                     \
+G_DEFINE_TYPE (camel, lower, type)                                        \
+G_MODULE_EXPORT GstClapperImporter *make_importer (void);                 \
+G_MODULE_EXPORT GstCaps *make_caps (GstRank *rank, GStrv *context_types);
+
+typedef struct _GstClapperImporter GstClapperImporter;
+typedef struct _GstClapperImporterClass GstClapperImporterClass;
+
+#ifdef G_DEFINE_AUTOPTR_CLEANUP_FUNC
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (GstClapperImporter, gst_object_unref)
+#endif
+
+struct _GstClapperImporter
+{
+  GstObject parent;
+
+  GstBuffer *pending_buffer, *buffer;
+  GPtrArray *pending_overlays, *overlays;
+  GstVideoInfo pending_v_info, v_info;
+  gboolean has_pending_v_info;
+
+  GdkTexture *texture;
+
+  GdkRGBA bg;
+};
+
+struct _GstClapperImporterClass
+{
+  GstObjectClass parent_class;
+
+  gboolean (* prepare) (GstClapperImporter *importer);
+
+  void (* share_data) (GstClapperImporter *src,
+                       GstClapperImporter *dest);
+
+  void (* set_caps) (GstClapperImporter *importer,
+                     GstCaps            *caps);
+
+  gboolean (* handle_context_query) (GstClapperImporter *importer,
+                                     GstBaseSink        *bsink,
+                                     GstQuery           *query);
+
+  GstBufferPool * (* create_pool) (GstClapperImporter *importer,
+                                   GstStructure      **config);
+
+  void (* add_allocation_metas) (GstClapperImporter *importer,
+                                 GstQuery           *query);
+
+  GdkTexture * (* generate_texture) (GstClapperImporter *importer,
+                                     GstBuffer          *buffer,
+                                     GstVideoInfo       *v_info);
+};
+
+GType           gst_clapper_importer_get_type                (void);
+
+gboolean        gst_clapper_importer_prepare                 (GstClapperImporter *importer);
+void            gst_clapper_importer_share_data              (GstClapperImporter *importer, GstClapperImporter *dest);
+gboolean        gst_clapper_importer_handle_context_query    (GstClapperImporter *importer, GstBaseSink *bsink, GstQuery *query);
+GstBufferPool * gst_clapper_importer_create_pool             (GstClapperImporter *importer, GstStructure **config);
+void            gst_clapper_importer_add_allocation_metas    (GstClapperImporter *importer, GstQuery *query);
+
+void            gst_clapper_importer_set_caps                (GstClapperImporter *importer, GstCaps *caps);
+void            gst_clapper_importer_set_buffer              (GstClapperImporter *importer, GstBuffer *buffer);
+
+void            gst_clapper_importer_snapshot                (GstClapperImporter *importer, GdkSnapshot *snapshot, gdouble width, gdouble height, gfloat scale_x, gfloat scale_y);
+
+G_END_DECLS

lib/gst/plugin/gstclapperimporterloader.c

@@ -0,0 +1,416 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gmodule.h>
+
+#include "gstclapperimporterloader.h"
+#include "gstclapperimporter.h"
+
+#define GST_CAT_DEFAULT gst_clapper_importer_loader_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+typedef GstClapperImporter* (* MakeImporter) (void);
+typedef GstCaps* (* MakeCaps) (GstRank *rank, GStrv *context_types);
+
+typedef struct
+{
+  gchar *module_path;
+  GModule *open_module;
+  GstCaps *caps;
+  GstRank rank;
+  GStrv context_types;
+} GstClapperImporterData;
+
+static void
+gst_clapper_importer_data_free (GstClapperImporterData *data)
+{
+  g_free (data->module_path);
+
+  if (data->open_module)
+    g_module_close (data->open_module);
+
+  gst_clear_caps (&data->caps);
+  g_strfreev (data->context_types);
+  g_free (data);
+}
+
+static gboolean
+_open_importer (GstClapperImporterData *data)
+{
+  g_return_val_if_fail (data && data->module_path, FALSE);
+
+  /* Already open */
+  if (data->open_module)
+    return TRUE;
+
+  GST_DEBUG ("Opening module: %s", data->module_path);
+  data->open_module = g_module_open (data->module_path, G_MODULE_BIND_LAZY);
+
+  if (!data->open_module) {
+    GST_WARNING ("Could not load importer: %s, reason: %s",
+        data->module_path, g_module_error ());
+    return FALSE;
+  }
+  GST_DEBUG ("Opened importer module");
+
+  /* Make sure module stays loaded. Seems to be needed for
+   * reusing exported symbols from the same module again */
+  g_module_make_resident (data->open_module);
+
+  return TRUE;
+}
+
+static void
+_close_importer (GstClapperImporterData *data)
+{
+  if (!data || !data->open_module)
+    return;
+
+  if (G_LIKELY (g_module_close (data->open_module)))
+    GST_DEBUG ("Closed module: %s", data->module_path);
+  else
+    GST_WARNING ("Could not close importer module");
+
+  data->open_module = NULL;
+}
+
+static GstClapperImporter *
+_obtain_importer_internal (GstClapperImporterData *data)
+{
+  MakeImporter make_importer;
+  GstClapperImporter *importer = NULL;
+
+  if (!_open_importer (data))
+    goto finish;
+
+  if (!g_module_symbol (data->open_module, "make_importer", (gpointer *) &make_importer)
+      || make_importer == NULL) {
+    GST_WARNING ("Make function missing in importer");
+    goto fail;
+  }
+
+  /* Do not close the module, we are gonna continue using it */
+  if ((importer = make_importer ()))
+    goto finish;
+
+fail:
+  _close_importer (data);
+
+finish:
+  return importer;
+}
+
+static GstClapperImporterData *
+_fill_importer_data (const gchar *module_path)
+{
+  MakeCaps make_caps;
+  GstClapperImporterData *data;
+
+  data = g_new0 (GstClapperImporterData, 1);
+  data->module_path = g_strdup (module_path);
+  data->open_module = g_module_open (data->module_path, G_MODULE_BIND_LAZY);
+
+  if (!data->open_module)
+    goto fail;
+
+  if (!g_module_symbol (data->open_module, "make_caps", (gpointer *) &make_caps)
+      || make_caps == NULL) {
+    GST_WARNING ("Make caps function missing in importer");
+    goto fail;
+  }
+
+  data->caps = make_caps (&data->rank, &data->context_types);
+  GST_DEBUG ("Caps reading %ssuccessful", data->caps ? "" : "un");
+
+  if (!data->caps)
+    goto fail;
+
+  /* Once we obtain importer data, close module afterwards */
+  _close_importer (data);
+
+  return data;
+
+fail:
+  gst_clapper_importer_data_free (data);
+
+  return NULL;
+}
+
+static gint
+_sort_importers_cb (gconstpointer a, gconstpointer b)
+{
+  GstClapperImporterData *data_a, *data_b;
+
+  data_a = *((GstClapperImporterData **) a);
+  data_b = *((GstClapperImporterData **) b);
+
+  return (data_b->rank - data_a->rank);
+}
+
+static gpointer
+_obtain_available_importers (G_GNUC_UNUSED gpointer data)
+{
+  GPtrArray *importers;
+  GFile *dir;
+  GFileEnumerator *dir_enum;
+  GError *error = NULL;
+
+  importers = g_ptr_array_new_with_free_func (
+      (GDestroyNotify) gst_clapper_importer_data_free);
+
+  GST_INFO ("Checking available clapper sink importers");
+
+  dir = g_file_new_for_path (CLAPPER_SINK_IMPORTER_PATH);
+
+  if ((dir_enum = g_file_enumerate_children (dir,
+      G_FILE_ATTRIBUTE_STANDARD_NAME,
+      G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS, NULL, &error))) {
+    while (TRUE) {
+      GFileInfo *info = NULL;
+      GstClapperImporterData *data;
+      gchar *module_path;
+      const gchar *module_name;
+
+      if (!g_file_enumerator_iterate (dir_enum, &info,
+          NULL, NULL, &error) || !info)
+        break;
+
+      module_name = g_file_info_get_name (info);
+
+      if (!g_str_has_suffix (module_name, G_MODULE_SUFFIX))
+        continue;
+
+      module_path = g_module_build_path (CLAPPER_SINK_IMPORTER_PATH, module_name);
+      data = _fill_importer_data (module_path);
+      g_free (module_path);
+
+      if (!data) {
+        GST_WARNING ("Could not read importer data: %s", module_name);
+        continue;
+      }
+
+      GST_INFO ("Found importer: %s, caps: %" GST_PTR_FORMAT, module_name, data->caps);
+      g_ptr_array_add (importers, data);
+    }
+  }
+
+  g_object_unref (dir);
+  g_object_unref (dir_enum);
+
+  if (error) {
+    GST_ERROR ("Could not load importer, reason: %s",
+        (error->message) ? error->message : "unknown");
+    g_error_free (error);
+  }
+
+  g_ptr_array_sort (importers, (GCompareFunc) _sort_importers_cb);
+
+  return importers;
+}
+
+static const GPtrArray *
+gst_clapper_importer_loader_get_available_importers (void)
+{
+  static GOnce once = G_ONCE_INIT;
+
+  g_once (&once, _obtain_available_importers, NULL);
+  return (const GPtrArray *) once.retval;
+}
+
+static GstClapperImporterData *
+_find_open_importer_data (const GPtrArray *importers)
+{
+  guint i;
+
+  for (i = 0; i < importers->len; i++) {
+    GstClapperImporterData *data = g_ptr_array_index (importers, i);
+
+    if (data->open_module)
+      return data;
+  }
+
+  return NULL;
+}
+
+static GstClapperImporterData *
+_get_importer_data_for_caps (const GPtrArray *importers, const GstCaps *caps)
+{
+  guint i;
+
+  for (i = 0; i < importers->len; i++) {
+    GstClapperImporterData *data = g_ptr_array_index (importers, i);
+
+    if (!gst_caps_is_always_compatible (caps, data->caps))
+      continue;
+
+    return data;
+  }
+
+  return NULL;
+}
+
+static GstClapperImporterData *
+_get_importer_data_for_context_type (const GPtrArray *importers, const gchar *context_type)
+{
+  guint i;
+
+  for (i = 0; i < importers->len; i++) {
+    GstClapperImporterData *data = g_ptr_array_index (importers, i);
+    guint j;
+
+    if (!data->context_types)
+      continue;
+
+    for (j = 0; data->context_types[j]; j++) {
+      if (strcmp (context_type, data->context_types[j]))
+        continue;
+
+      return data;
+    }
+  }
+
+  return NULL;
+}
+
+void
+gst_clapper_importer_loader_unload_all (void)
+{
+  const GPtrArray *importers;
+  guint i;
+
+  importers = gst_clapper_importer_loader_get_available_importers ();
+  GST_TRACE ("Unloading all open modules");
+
+  for (i = 0; i < importers->len; i++) {
+    GstClapperImporterData *data = g_ptr_array_index (importers, i);
+
+    _close_importer (data);
+  }
+}
+
+GstPadTemplate *
+gst_clapper_importer_loader_make_sink_pad_template (void)
+{
+  const GPtrArray *importers;
+  GstCaps *sink_caps;
+  GstPadTemplate *templ;
+  guint i;
+
+  /* This is only called once from sink class init function */
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperimporterloader", 0,
+      "Clapper Importer Loader");
+
+  importers = gst_clapper_importer_loader_get_available_importers ();
+  sink_caps = gst_caps_new_empty ();
+
+  for (i = 0; i < importers->len; i++) {
+    GstClapperImporterData *data = g_ptr_array_index (importers, i);
+    GstCaps *copied_caps;
+
+    copied_caps = gst_caps_copy (data->caps);
+    gst_caps_append (sink_caps, copied_caps);
+  }
+
+  if (G_UNLIKELY (gst_caps_is_empty (sink_caps)))
+    gst_caps_append (sink_caps, gst_caps_new_any ());
+
+  templ = gst_pad_template_new ("sink", GST_PAD_SINK, GST_PAD_ALWAYS, sink_caps);
+  gst_caps_unref (sink_caps);
+
+  return templ;
+}
+
+static gboolean
+_find_importer_internal (GstCaps *caps, GstQuery *query, GstClapperImporter **importer)
+{
+  const GPtrArray *importers;
+  GstClapperImporterData *old_data = NULL, *new_data = NULL;
+  GstClapperImporter *found_importer = NULL;
+
+  importers = gst_clapper_importer_loader_get_available_importers ();
+  old_data = _find_open_importer_data (importers);
+
+  if (caps) {
+    GST_DEBUG ("Requested importer for caps: %" GST_PTR_FORMAT, caps);
+    new_data = _get_importer_data_for_caps (importers, caps);
+  } else if (query) {
+    const gchar *context_type;
+
+    gst_query_parse_context_type (query, &context_type);
+
+    GST_DEBUG ("Requested importer for context: %s", context_type);
+    new_data = _get_importer_data_for_context_type (importers, context_type);
+
+    /* In case missing importer for context query, leave the old one.
+     * We should allow some queries to go through unresponded */
+    if (!new_data)
+      new_data = old_data;
+  }
+  GST_LOG ("Old importer path: %s, new path: %s",
+      (old_data != NULL) ? old_data->module_path : NULL,
+      (new_data != NULL) ? new_data->module_path : NULL);
+
+  if (old_data == new_data) {
+    GST_DEBUG ("No importer change");
+
+    if (*importer && caps)
+      gst_clapper_importer_set_caps (*importer, caps);
+
+    return (*importer != NULL);
+  }
+
+  if (new_data) {
+    found_importer = _obtain_importer_internal (new_data);
+
+    if (*importer && found_importer)
+      gst_clapper_importer_share_data (*importer, found_importer);
+  }
+
+  gst_clear_object (importer);
+  _close_importer (old_data);
+
+  if (found_importer && gst_clapper_importer_prepare (found_importer)) {
+    if (caps)
+      gst_clapper_importer_set_caps (found_importer, caps);
+
+    *importer = found_importer;
+    return TRUE;
+  }
+
+  gst_clear_object (&found_importer);
+  _close_importer (new_data);
+
+  return FALSE;
+}
+
+gboolean
+gst_clapper_importer_loader_find_importer_for_caps (GstCaps *caps, GstClapperImporter **importer)
+{
+  return _find_importer_internal (caps, NULL, importer);
+}
+
+gboolean
+gst_clapper_importer_loader_find_importer_for_context_query (GstQuery *query, GstClapperImporter **importer)
+{
+  return _find_importer_internal (NULL, query, importer);
+}

lib/gst/plugin/gstclapperimporterloader.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+#include <gst/gst.h>
+
+#include "gstclapperimporter.h"
+
+G_BEGIN_DECLS
+
+GstPadTemplate * gst_clapper_importer_loader_make_sink_pad_template          (void);
+
+gboolean         gst_clapper_importer_loader_find_importer_for_caps          (GstCaps *caps, GstClapperImporter **importer);
+
+gboolean         gst_clapper_importer_loader_find_importer_for_context_query (GstQuery *query, GstClapperImporter **importer);
+
+void             gst_clapper_importer_loader_unload_all                      (void);
+
+G_END_DECLS

lib/gst/plugin/gstclapperpaintable.c

@@ -0,0 +1,428 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstclapperpaintable.h"
+
+#define DEFAULT_PAR_N               1
+#define DEFAULT_PAR_D               1
+
+#define GST_CAT_DEFAULT gst_clapper_paintable_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+static void gst_clapper_paintable_iface_init (GdkPaintableInterface *iface);
+static void gst_clapper_paintable_dispose (GObject *object);
+static void gst_clapper_paintable_finalize (GObject *object);
+
+#define parent_class gst_clapper_paintable_parent_class
+G_DEFINE_TYPE_WITH_CODE (GstClapperPaintable, gst_clapper_paintable, G_TYPE_OBJECT,
+    G_IMPLEMENT_INTERFACE (GDK_TYPE_PAINTABLE,
+        gst_clapper_paintable_iface_init));
+
+static void
+gst_clapper_paintable_class_init (GstClapperPaintableClass *klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperpaintable", 0,
+      "Clapper Paintable");
+
+  gobject_class->dispose = gst_clapper_paintable_dispose;
+  gobject_class->finalize = gst_clapper_paintable_finalize;
+}
+
+static void
+gst_clapper_paintable_init (GstClapperPaintable *self)
+{
+  self->par_n = DEFAULT_PAR_N;
+  self->par_d = DEFAULT_PAR_D;
+  self->pixel_aspect = ((gdouble) self->par_d / self->par_n);
+
+  g_mutex_init (&self->lock);
+  gst_video_info_init (&self->v_info);
+  g_weak_ref_init (&self->widget, NULL);
+  g_weak_ref_init (&self->importer, NULL);
+
+  gdk_rgba_parse (&self->bg, "black");
+}
+
+static void
+gst_clapper_paintable_dispose (GObject *object)
+{
+  GstClapperPaintable *self = GST_CLAPPER_PAINTABLE (object);
+
+  GST_CLAPPER_PAINTABLE_LOCK (self);
+
+  if (self->draw_id > 0) {
+    g_source_remove (self->draw_id);
+    self->draw_id = 0;
+  }
+
+  GST_CLAPPER_PAINTABLE_UNLOCK (self);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, dispose, (object));
+}
+
+static void
+gst_clapper_paintable_finalize (GObject *object)
+{
+  GstClapperPaintable *self = GST_CLAPPER_PAINTABLE (object);
+
+  GST_TRACE ("Finalize");
+
+  g_weak_ref_clear (&self->widget);
+  g_weak_ref_clear (&self->importer);
+  g_mutex_clear (&self->lock);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
+}
+
+static gboolean
+calculate_display_par (GstClapperPaintable *self, const GstVideoInfo *info)
+{
+  gint width, height, par_n, par_d, req_par_n, req_par_d;
+  gboolean success;
+
+  width = GST_VIDEO_INFO_WIDTH (info);
+  height = GST_VIDEO_INFO_HEIGHT (info);
+
+  /* Cannot apply aspect ratio if there is no video */
+  if (width == 0 || height == 0)
+    return FALSE;
+
+  par_n = GST_VIDEO_INFO_PAR_N (info);
+  par_d = GST_VIDEO_INFO_PAR_D (info);
+
+  req_par_n = self->par_n;
+  req_par_d = self->par_d;
+
+  if (par_n == 0)
+    par_n = 1;
+
+  /* Use defaults if user set zero */
+  if (req_par_n == 0 || req_par_d == 0) {
+    req_par_n = DEFAULT_PAR_N;
+    req_par_d = DEFAULT_PAR_D;
+  }
+
+  GST_LOG_OBJECT (self, "PAR: %u/%u, DAR: %u/%u", par_n, par_d, req_par_n, req_par_d);
+
+  if (!(success = gst_video_calculate_display_ratio (&self->display_ratio_num,
+      &self->display_ratio_den, width, height, par_n, par_d,
+      req_par_n, req_par_d))) {
+    GST_ERROR_OBJECT (self, "Could not calculate display ratio values");
+  }
+
+  return success;
+}
+
+static void
+invalidate_paintable_size_internal (GstClapperPaintable *self)
+{
+  gint video_width, video_height;
+  guint display_ratio_num, display_ratio_den;
+
+  GST_CLAPPER_PAINTABLE_LOCK (self);
+
+  video_width = GST_VIDEO_INFO_WIDTH (&self->v_info);
+  video_height = GST_VIDEO_INFO_HEIGHT (&self->v_info);
+
+  display_ratio_num = self->display_ratio_num;
+  display_ratio_den = self->display_ratio_den;
+
+  self->pixel_aspect = ((gdouble) self->par_d / self->par_n);
+
+  GST_CLAPPER_PAINTABLE_UNLOCK (self);
+
+  if (video_height % display_ratio_den == 0) {
+    GST_LOG ("Keeping video height");
+
+    self->display_width = (guint)
+        gst_util_uint64_scale_int (video_height, display_ratio_num, display_ratio_den);
+    self->display_height = video_height;
+  } else if (video_width % display_ratio_num == 0) {
+    GST_LOG ("Keeping video width");
+
+    self->display_width = video_width;
+    self->display_height = (guint)
+        gst_util_uint64_scale_int (video_width, display_ratio_den, display_ratio_num);
+  } else {
+    GST_LOG ("Approximating while keeping video height");
+
+    self->display_width = (guint)
+        gst_util_uint64_scale_int (video_height, display_ratio_num, display_ratio_den);
+    self->display_height = video_height;
+  }
+
+  self->display_aspect_ratio = ((gdouble) self->display_width
+      / (gdouble) self->display_height);
+
+  GST_DEBUG_OBJECT (self, "Invalidate paintable size, display: %dx%d",
+      self->display_width, self->display_height);
+  gdk_paintable_invalidate_size ((GdkPaintable *) self);
+}
+
+static gboolean
+invalidate_paintable_size_on_main_cb (GstClapperPaintable *self)
+{
+  GST_CLAPPER_PAINTABLE_LOCK (self);
+  self->draw_id = 0;
+  GST_CLAPPER_PAINTABLE_UNLOCK (self);
+
+  invalidate_paintable_size_internal (self);
+
+  return G_SOURCE_REMOVE;
+}
+
+static gboolean
+update_paintable_on_main_cb (GstClapperPaintable *self)
+{
+  gboolean size_changed;
+
+  GST_CLAPPER_PAINTABLE_LOCK (self);
+
+  /* Check if we will need to invalidate size */
+  if ((size_changed = self->pending_resize))
+    self->pending_resize = FALSE;
+
+  self->draw_id = 0;
+
+  GST_CLAPPER_PAINTABLE_UNLOCK (self);
+
+  if (size_changed)
+    invalidate_paintable_size_internal (self);
+
+  GST_LOG_OBJECT (self, "Invalidate paintable contents");
+  gdk_paintable_invalidate_contents ((GdkPaintable *) self);
+
+  return G_SOURCE_REMOVE;
+}
+
+GstClapperPaintable *
+gst_clapper_paintable_new (void)
+{
+  return g_object_new (GST_TYPE_CLAPPER_PAINTABLE, NULL);
+}
+
+void
+gst_clapper_paintable_set_widget (GstClapperPaintable *self, GtkWidget *widget)
+{
+  g_weak_ref_set (&self->widget, widget);
+}
+
+void
+gst_clapper_paintable_set_importer (GstClapperPaintable *self, GstClapperImporter *importer)
+{
+  g_weak_ref_set (&self->importer, importer);
+}
+
+void
+gst_clapper_paintable_queue_draw (GstClapperPaintable *self)
+{
+  GST_CLAPPER_PAINTABLE_LOCK (self);
+
+  if (self->draw_id > 0) {
+    GST_CLAPPER_PAINTABLE_UNLOCK (self);
+    GST_TRACE ("Already have pending draw");
+
+    return;
+  }
+
+  self->draw_id = g_idle_add_full (G_PRIORITY_DEFAULT,
+      (GSourceFunc) update_paintable_on_main_cb, self, NULL);
+
+  GST_CLAPPER_PAINTABLE_UNLOCK (self);
+}
+
+gboolean
+gst_clapper_paintable_set_video_info (GstClapperPaintable *self, const GstVideoInfo *v_info)
+{
+  GST_CLAPPER_PAINTABLE_LOCK (self);
+
+  if (gst_video_info_is_equal (&self->v_info, v_info)) {
+    GST_CLAPPER_PAINTABLE_UNLOCK (self);
+    return TRUE;
+  }
+
+  /* Reject info if values would cause integer overflow */
+  if (G_UNLIKELY (!calculate_display_par (self, v_info))) {
+    GST_CLAPPER_PAINTABLE_UNLOCK (self);
+    return FALSE;
+  }
+
+  self->pending_resize = TRUE;
+  self->v_info = *v_info;
+
+  GST_CLAPPER_PAINTABLE_UNLOCK (self);
+
+  return TRUE;
+}
+
+void
+gst_clapper_paintable_set_pixel_aspect_ratio (GstClapperPaintable *self,
+    gint par_n, gint par_d)
+{
+  gboolean success;
+
+  GST_CLAPPER_PAINTABLE_LOCK (self);
+
+  /* No change */
+  if (self->par_n == par_n && self->par_d == par_d) {
+    GST_CLAPPER_PAINTABLE_UNLOCK (self);
+    return;
+  }
+
+  self->par_n = par_n;
+  self->par_d = par_d;
+
+  /* Check if we can accept new values. This will update
+   * display `ratio_num` and `ratio_den` only when successful */
+  success = calculate_display_par (self, &self->v_info);
+
+  /* If paintable update is queued, wait for it, otherwise invalidate
+   * size only for change to be applied even when paused */
+  if (!success || self->draw_id > 0) {
+    self->pending_resize = success;
+    GST_CLAPPER_PAINTABLE_UNLOCK (self);
+
+    return;
+  }
+
+  self->draw_id = g_idle_add_full (G_PRIORITY_DEFAULT,
+      (GSourceFunc) invalidate_paintable_size_on_main_cb, self, NULL);
+
+  GST_CLAPPER_PAINTABLE_UNLOCK (self);
+}
+
+/*
+ * GdkPaintableInterface
+ */
+static void
+gst_clapper_paintable_snapshot_internal (GstClapperPaintable *self,
+    GdkSnapshot *snapshot, gdouble width, gdouble height,
+    gint widget_width, gint widget_height)
+{
+  GstClapperImporter *importer;
+  gfloat scale_x, scale_y;
+
+  GST_LOG_OBJECT (self, "Snapshot");
+
+  scale_x = (gfloat) width / self->display_width;
+  scale_y = (gfloat) height / self->display_height;
+
+  /* Apply black borders when keeping aspect ratio */
+  if (scale_x == scale_y || abs (scale_x - scale_y) <= FLT_EPSILON) {
+    if (widget_height - height > 0) {
+      /* XXX: Top uses integer to work with GTK rounding (not going offscreen) */
+      gint top_bar_height = (widget_height - height) / 2;
+      gdouble bottom_bar_height = (widget_height - top_bar_height - height);
+
+      gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, 0, width, -top_bar_height));
+      gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, height, width, bottom_bar_height));
+    } else if (widget_width - width > 0) {
+      gint left_bar_width = (widget_width - width) / 2;
+      gdouble right_bar_width = (widget_width - left_bar_width - width);
+
+      gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, 0, -left_bar_width, height));
+      gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (width, 0, right_bar_width, height));
+    }
+  }
+
+  if ((importer = g_weak_ref_get (&self->importer))) {
+    gst_clapper_importer_snapshot (importer, snapshot, width, height,
+        scale_x * self->pixel_aspect, scale_y);
+    g_object_unref (importer);
+  } else {
+    GST_LOG_OBJECT (self, "No texture importer, drawing black");
+    gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, 0, width, height));
+  }
+}
+
+static void
+gst_clapper_paintable_snapshot (GdkPaintable *paintable,
+    GdkSnapshot *snapshot, gdouble width, gdouble height)
+{
+  GstClapperPaintable *self = GST_CLAPPER_PAINTABLE_CAST (paintable);
+  GtkWidget *widget;
+  gint widget_width = 0, widget_height = 0;
+
+  if ((widget = g_weak_ref_get (&self->widget))) {
+    gint scale_factor;
+
+    scale_factor = gtk_widget_get_scale_factor (widget);
+    widget_width = gtk_widget_get_width (widget) * scale_factor;
+    widget_height = gtk_widget_get_height (widget) * scale_factor;
+
+    g_object_unref (widget);
+  }
+
+  gst_clapper_paintable_snapshot_internal (self, snapshot,
+      width, height, widget_width, widget_height);
+}
+
+static GdkPaintable *
+gst_clapper_paintable_get_current_image (GdkPaintable *paintable)
+{
+  GstClapperPaintable *self = GST_CLAPPER_PAINTABLE_CAST (paintable);
+  GtkSnapshot *snapshot = gtk_snapshot_new ();
+
+  /* Snapshot without widget size in order to get
+   * paintable without black borders */
+  gst_clapper_paintable_snapshot_internal (self, snapshot,
+      self->display_width, self->display_height, 0, 0);
+
+  return gtk_snapshot_free_to_paintable (snapshot, NULL);
+}
+
+static gint
+gst_clapper_paintable_get_intrinsic_width (GdkPaintable *paintable)
+{
+  GstClapperPaintable *self = GST_CLAPPER_PAINTABLE_CAST (paintable);
+
+  return self->display_width;
+}
+
+static gint
+gst_clapper_paintable_get_intrinsic_height (GdkPaintable *paintable)
+{
+  GstClapperPaintable *self = GST_CLAPPER_PAINTABLE_CAST (paintable);
+
+  return self->display_height;
+}
+
+static gdouble
+gst_clapper_paintable_get_intrinsic_aspect_ratio (GdkPaintable *paintable)
+{
+  GstClapperPaintable *self = GST_CLAPPER_PAINTABLE_CAST (paintable);
+
+  return self->display_aspect_ratio;
+}
+
+static void
+gst_clapper_paintable_iface_init (GdkPaintableInterface *iface)
+{
+  iface->snapshot = gst_clapper_paintable_snapshot;
+  iface->get_current_image = gst_clapper_paintable_get_current_image;
+  iface->get_intrinsic_width = gst_clapper_paintable_get_intrinsic_width;
+  iface->get_intrinsic_height = gst_clapper_paintable_get_intrinsic_height;
+  iface->get_intrinsic_aspect_ratio = gst_clapper_paintable_get_intrinsic_aspect_ratio;
+}

lib/gst/plugin/gstclapperpaintable.h

@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+#include <gtk/gtk.h>
+#include <gst/gst.h>
+#include <gst/video/video.h>
+
+#include "gstclapperimporter.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_PAINTABLE (gst_clapper_paintable_get_type())
+G_DECLARE_FINAL_TYPE (GstClapperPaintable, gst_clapper_paintable, GST, CLAPPER_PAINTABLE, GObject)
+
+#define GST_CLAPPER_PAINTABLE_CAST(obj)          ((GstClapperPaintable *)(obj))
+
+#define GST_CLAPPER_PAINTABLE_GET_LOCK(obj)      (&GST_CLAPPER_PAINTABLE_CAST(obj)->lock)
+#define GST_CLAPPER_PAINTABLE_LOCK(obj)          g_mutex_lock (GST_CLAPPER_PAINTABLE_GET_LOCK(obj))
+#define GST_CLAPPER_PAINTABLE_UNLOCK(obj)        g_mutex_unlock (GST_CLAPPER_PAINTABLE_GET_LOCK(obj))
+
+struct _GstClapperPaintable
+{
+  GObject parent;
+
+  GMutex lock;
+
+  GstVideoInfo v_info;
+
+  GdkRGBA bg;
+
+  GWeakRef widget, importer;
+
+  /* Sink properties */
+  gint par_n, par_d;
+
+  /* For drawing overlays */
+  gdouble pixel_aspect;
+
+  /* Resize */
+  gboolean pending_resize;
+  guint display_ratio_num;
+  guint display_ratio_den;
+
+  /* GdkPaintableInterface */
+  gint display_width;
+  gint display_height;
+  gdouble display_aspect_ratio;
+
+  /* Pending draw signal id */
+  guint draw_id;
+};
+
+GstClapperPaintable * gst_clapper_paintable_new                    (void);
+void                  gst_clapper_paintable_queue_draw             (GstClapperPaintable *paintable);
+void                  gst_clapper_paintable_set_widget             (GstClapperPaintable *paintable, GtkWidget *widget);
+void                  gst_clapper_paintable_set_importer           (GstClapperPaintable *paintable, GstClapperImporter *importer);
+gboolean              gst_clapper_paintable_set_video_info         (GstClapperPaintable *paintable, const GstVideoInfo *v_info);
+void                  gst_clapper_paintable_set_pixel_aspect_ratio (GstClapperPaintable *paintable, gint par_n, gint par_d);
+
+G_END_DECLS

lib/gst/plugin/gstclappersink.c

@@ -0,0 +1,910 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstclappersink.h"
+#include "gstclapperimporterloader.h"
+#include "gstgtkutils.h"
+
+#define DEFAULT_FORCE_ASPECT_RATIO  TRUE
+#define DEFAULT_PAR_N               1
+#define DEFAULT_PAR_D               1
+#define DEFAULT_KEEP_LAST_FRAME     FALSE
+
+#define WINDOW_CSS_CLASS_NAME       "clappersinkwindow"
+
+enum
+{
+  PROP_0,
+  PROP_WIDGET,
+  PROP_FORCE_ASPECT_RATIO,
+  PROP_PIXEL_ASPECT_RATIO,
+  PROP_KEEP_LAST_FRAME,
+  PROP_LAST
+};
+
+#define GST_CAT_DEFAULT gst_clapper_sink_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+static void gst_clapper_sink_navigation_interface_init (
+    GstNavigationInterface *iface);
+
+#define parent_class gst_clapper_sink_parent_class
+G_DEFINE_TYPE_WITH_CODE (GstClapperSink, gst_clapper_sink, GST_TYPE_VIDEO_SINK,
+    G_IMPLEMENT_INTERFACE (GST_TYPE_NAVIGATION,
+        gst_clapper_sink_navigation_interface_init));
+GST_ELEMENT_REGISTER_DEFINE (clappersink, "clappersink", GST_RANK_NONE,
+    GST_TYPE_CLAPPER_SINK);
+
+static void
+window_clear_no_lock (GstClapperSink *self)
+{
+  if (!self->window)
+    return;
+
+  GST_TRACE_OBJECT (self, "Window clear");
+
+  if (self->window_destroy_id) {
+    g_signal_handler_disconnect (self->window, self->window_destroy_id);
+    self->window_destroy_id = 0;
+  }
+  self->window = NULL;
+  self->presented_window = FALSE;
+}
+
+static void
+widget_clear_no_lock (GstClapperSink *self)
+{
+  if (!self->widget)
+    return;
+
+  GST_TRACE_OBJECT (self, "Widget clear");
+
+  if (self->widget_destroy_id) {
+    g_signal_handler_disconnect (self->widget, self->widget_destroy_id);
+    self->widget_destroy_id = 0;
+  }
+  g_clear_object (&self->widget);
+}
+
+static void
+widget_destroy_cb (GtkWidget *widget, GstClapperSink *self)
+{
+  GST_CLAPPER_SINK_LOCK (self);
+  widget_clear_no_lock (self);
+  GST_CLAPPER_SINK_UNLOCK (self);
+}
+
+static void
+window_destroy_cb (GtkWidget *window, GstClapperSink *self)
+{
+  GST_DEBUG_OBJECT (self, "Window destroy");
+
+  GST_CLAPPER_SINK_LOCK (self);
+
+  widget_clear_no_lock (self);
+  window_clear_no_lock (self);
+
+  GST_CLAPPER_SINK_UNLOCK (self);
+}
+
+static void
+calculate_stream_coords (GstClapperSink *self, GtkWidget *widget,
+    gdouble x, gdouble y, gdouble *stream_x, gdouble *stream_y)
+{
+  GstVideoRectangle result;
+  gint scaled_width, scaled_height, scale_factor;
+  gint video_width, video_height;
+  gboolean force_aspect_ratio;
+
+  GST_CLAPPER_SINK_LOCK (self);
+
+  video_width = GST_VIDEO_INFO_WIDTH (&self->v_info);
+  video_height = GST_VIDEO_INFO_HEIGHT (&self->v_info);
+  force_aspect_ratio = self->force_aspect_ratio;
+
+  GST_CLAPPER_SINK_UNLOCK (self);
+
+  scale_factor = gtk_widget_get_scale_factor (widget);
+  scaled_width = gtk_widget_get_width (widget) * scale_factor;
+  scaled_height = gtk_widget_get_height (widget) * scale_factor;
+
+  if (force_aspect_ratio) {
+    GstVideoRectangle src, dst;
+
+    src.x = 0;
+    src.y = 0;
+    src.w = gdk_paintable_get_intrinsic_width ((GdkPaintable *) self->paintable);
+    src.h = gdk_paintable_get_intrinsic_height ((GdkPaintable *) self->paintable);
+
+    dst.x = 0;
+    dst.y = 0;
+    dst.w = scaled_width;
+    dst.h = scaled_height;
+
+    gst_video_center_rect (&src, &dst, &result, TRUE);
+  } else {
+    result.x = 0;
+    result.y = 0;
+    result.w = scaled_width;
+    result.h = scaled_height;
+  }
+
+  /* Display coordinates to stream coordinates */
+  *stream_x = (result.w > 0)
+      ? (x - result.x) / result.w * video_width
+      : 0;
+  *stream_y = (result.h > 0)
+      ? (y - result.y) / result.h * video_height
+      : 0;
+
+  /* Clip to stream size */
+  *stream_x = CLAMP (*stream_x, 0, video_width);
+  *stream_y = CLAMP (*stream_y, 0, video_height);
+
+  GST_LOG ("Transform coords %fx%f => %fx%f", x, y, *stream_x, *stream_y);
+}
+
+static void
+gst_clapper_sink_widget_motion_event (GtkEventControllerMotion *motion,
+    gdouble x, gdouble y, GstClapperSink *self)
+{
+  GtkWidget *widget;
+  gdouble stream_x, stream_y;
+  gboolean is_inactive;
+
+  if (x == self->last_pos_x && y == self->last_pos_y)
+    return;
+
+  GST_OBJECT_LOCK (self);
+  is_inactive = (GST_STATE (self) < GST_STATE_PLAYING);
+  GST_OBJECT_UNLOCK (self);
+
+  if (is_inactive)
+    return;
+
+  self->last_pos_x = x;
+  self->last_pos_y = y;
+
+  widget = gtk_event_controller_get_widget ((GtkEventController *) motion);
+  calculate_stream_coords (self, widget, x, y, &stream_x, &stream_y);
+  GST_LOG ("Event \"mouse-move\", x: %f, y: %f", stream_x, stream_y);
+
+  gst_navigation_send_mouse_event ((GstNavigation *) self, "mouse-move",
+      0, stream_x, stream_y);
+}
+
+static void
+gst_clapper_sink_widget_button_event (GtkGestureClick *click,
+    gint n_press, gdouble x, gdouble y, GstClapperSink *self)
+{
+  GtkWidget *widget;
+  GdkEvent *event;
+  GdkEventType event_type;
+  const gchar *event_name;
+  gdouble stream_x, stream_y;
+  gboolean is_inactive;
+
+  GST_OBJECT_LOCK (self);
+  is_inactive = (GST_STATE (self) < GST_STATE_PLAYING);
+  GST_OBJECT_UNLOCK (self);
+
+  if (is_inactive)
+    return;
+
+  event = gtk_event_controller_get_current_event ((GtkEventController *) click);
+  event_type = gdk_event_get_event_type (event);
+
+  /* FIXME: Touchscreen handling should probably use new touch events from GStreamer 1.22 */
+  event_name = (event_type == GDK_BUTTON_PRESS || event_type == GDK_TOUCH_BEGIN)
+      ? "mouse-button-press"
+      : (event_type == GDK_BUTTON_RELEASE || event_type == GDK_TOUCH_END)
+      ? "mouse-button-release"
+      : NULL;
+
+  /* Can be NULL on touch */
+  if (!event_name)
+    return;
+
+  widget = gtk_event_controller_get_widget ((GtkEventController *) click);
+  calculate_stream_coords (self, widget, x, y, &stream_x, &stream_y);
+  GST_LOG ("Event \"%s\", x: %f, y: %f", event_name, stream_x, stream_y);
+
+  /* Gesture is set to handle only primary button, so we do not have to check */
+  gst_navigation_send_mouse_event ((GstNavigation *) self, event_name,
+      1, stream_x, stream_y);
+}
+
+/* Must call from main thread only with a lock */
+static GtkWidget *
+gst_clapper_sink_get_widget (GstClapperSink *self)
+{
+  if (G_UNLIKELY (!self->widget)) {
+    GtkEventController *controller;
+    GtkGesture *gesture;
+
+    /* Make sure GTK is initialized */
+    if (!gtk_init_check ()) {
+      GST_ERROR_OBJECT (self, "Could not ensure GTK initialization");
+      return NULL;
+    }
+
+    self->widget = gtk_picture_new ();
+
+    /* Otherwise widget in grid will appear as a 1x1px
+     * video which might be misleading for users */
+    gtk_widget_set_hexpand (self->widget, TRUE);
+    gtk_widget_set_vexpand (self->widget, TRUE);
+
+    gtk_widget_set_focusable (self->widget, TRUE);
+    gtk_widget_set_can_focus (self->widget, TRUE);
+
+    controller = gtk_event_controller_motion_new ();
+    g_signal_connect (controller, "motion",
+        G_CALLBACK (gst_clapper_sink_widget_motion_event), self);
+    gtk_widget_add_controller (self->widget, controller);
+
+    gesture = gtk_gesture_click_new ();
+    gtk_gesture_single_set_button (GTK_GESTURE_SINGLE (gesture), 1);
+    g_signal_connect (gesture, "pressed",
+        G_CALLBACK (gst_clapper_sink_widget_button_event), self);
+    g_signal_connect (gesture, "released",
+        G_CALLBACK (gst_clapper_sink_widget_button_event), self);
+    gtk_widget_add_controller (self->widget, GTK_EVENT_CONTROLLER (gesture));
+
+    /* TODO: Implement touch events once we depend on GStreamer 1.22 */
+
+    /* Take floating ref */
+    g_object_ref_sink (self->widget);
+
+    /* Set widget back pointer */
+    gst_clapper_paintable_set_widget (self->paintable, self->widget);
+
+    /* Set earlier remembered property */
+    gtk_picture_set_keep_aspect_ratio (GTK_PICTURE (self->widget),
+        self->force_aspect_ratio);
+
+    gtk_picture_set_paintable (GTK_PICTURE (self->widget), GDK_PAINTABLE (self->paintable));
+
+    self->widget_destroy_id = g_signal_connect (self->widget,
+        "destroy", G_CALLBACK (widget_destroy_cb), self);
+  }
+
+  return self->widget;
+}
+
+static GtkWidget *
+gst_clapper_sink_obtain_widget (GstClapperSink *self)
+{
+  GtkWidget *widget;
+
+  GST_CLAPPER_SINK_LOCK (self);
+  widget = gst_clapper_sink_get_widget (self);
+  if (widget)
+    g_object_ref (widget);
+  GST_CLAPPER_SINK_UNLOCK (self);
+
+  return widget;
+}
+
+static void
+gst_clapper_sink_get_property (GObject *object, guint prop_id,
+    GValue *value, GParamSpec *pspec)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (object);
+
+  GST_CLAPPER_SINK_LOCK (self);
+
+  switch (prop_id) {
+    case PROP_WIDGET:
+      if (self->widget) {
+        g_value_set_object (value, self->widget);
+      } else {
+        GtkWidget *widget;
+
+        GST_CLAPPER_SINK_UNLOCK (self);
+        widget = gst_gtk_invoke_on_main ((GThreadFunc) gst_clapper_sink_obtain_widget, self);
+        GST_CLAPPER_SINK_LOCK (self);
+
+        g_value_set_object (value, widget);
+        g_object_unref (widget);
+      }
+      break;
+    case PROP_FORCE_ASPECT_RATIO:
+      g_value_set_boolean (value, self->force_aspect_ratio);
+      break;
+    case PROP_PIXEL_ASPECT_RATIO:
+      gst_value_set_fraction (value, self->par_n, self->par_d);
+      break;
+    case PROP_KEEP_LAST_FRAME:
+      g_value_set_boolean (value, self->keep_last_frame);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+
+  GST_CLAPPER_SINK_UNLOCK (self);
+}
+
+static void
+gst_clapper_sink_set_property (GObject *object, guint prop_id,
+    const GValue *value, GParamSpec *pspec)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (object);
+
+  GST_CLAPPER_SINK_LOCK (self);
+
+  switch (prop_id) {
+    case PROP_FORCE_ASPECT_RATIO:
+      self->force_aspect_ratio = g_value_get_boolean (value);
+
+      if (self->widget) {
+        gtk_picture_set_keep_aspect_ratio (GTK_PICTURE (self->widget),
+            self->force_aspect_ratio);
+      }
+      break;
+    case PROP_PIXEL_ASPECT_RATIO:
+      self->par_n = gst_value_get_fraction_numerator (value);
+      self->par_d = gst_value_get_fraction_denominator (value);
+
+      gst_clapper_paintable_set_pixel_aspect_ratio (self->paintable,
+          self->par_n, self->par_d);
+      break;
+    case PROP_KEEP_LAST_FRAME:
+      self->keep_last_frame = g_value_get_boolean (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+
+  GST_CLAPPER_SINK_UNLOCK (self);
+}
+
+static void
+gst_clapper_sink_navigation_send_event (GstNavigation *navigation,
+    GstStructure *structure)
+{
+  GstClapperSink *sink = GST_CLAPPER_SINK_CAST (navigation);
+  GstEvent *event;
+
+  GST_TRACE_OBJECT (sink, "Navigation event: %" GST_PTR_FORMAT, structure);
+  event = gst_event_new_navigation (structure);
+
+  if (G_LIKELY (event)) {
+    GstPad *pad;
+
+    pad = gst_pad_get_peer (GST_VIDEO_SINK_PAD (sink));
+
+    if (G_LIKELY (pad)) {
+      if (!gst_pad_send_event (pad, gst_event_ref (event))) {
+        /* If upstream didn't handle the event we'll post a message with it
+         * for the application in case it wants to do something with it */
+        gst_element_post_message (GST_ELEMENT_CAST (sink),
+            gst_navigation_message_new_event (GST_OBJECT_CAST (sink), event));
+      }
+      gst_object_unref (pad);
+    }
+    gst_event_unref (event);
+  }
+}
+
+static gboolean
+gst_clapper_sink_propose_allocation (GstBaseSink *bsink, GstQuery *query)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (bsink);
+  GstBufferPool *pool = NULL;
+  GstCaps *caps;
+  GstVideoInfo info;
+  guint size, min_buffers;
+  gboolean need_pool;
+
+  gst_query_parse_allocation (query, &caps, &need_pool);
+
+  if (!caps) {
+    GST_DEBUG_OBJECT (self, "No caps specified");
+    return FALSE;
+  }
+
+  if (!gst_video_info_from_caps (&info, caps)) {
+    GST_DEBUG_OBJECT (self, "Invalid caps specified");
+    return FALSE;
+  }
+
+  /* Normal size of a frame */
+  size = GST_VIDEO_INFO_SIZE (&info);
+
+  /* We keep around current buffer and a pending one */
+  min_buffers = 3;
+
+  if (need_pool) {
+    GstStructure *config = NULL;
+
+    GST_DEBUG_OBJECT (self, "Need to create buffer pool");
+
+    GST_CLAPPER_SINK_LOCK (self);
+    pool = gst_clapper_importer_create_pool (self->importer, &config);
+    GST_CLAPPER_SINK_UNLOCK (self);
+
+    if (pool) {
+      /* If we did not get config, use default one */
+      if (!config)
+        config = gst_buffer_pool_get_config (pool);
+
+      gst_buffer_pool_config_set_params (config, caps, size, min_buffers, 0);
+
+      if (!gst_buffer_pool_set_config (pool, config)) {
+        gst_object_unref (pool);
+
+        GST_ERROR_OBJECT (self, "Failed to set config");
+        return FALSE;
+      }
+    } else if (config) {
+      GST_WARNING_OBJECT (self, "Got config without a pool to apply it");
+      gst_structure_free (config);
+    }
+  }
+
+  gst_query_add_allocation_pool (query, pool, size, min_buffers, 0);
+  if (pool)
+    gst_object_unref (pool);
+
+  GST_CLAPPER_SINK_LOCK (self);
+  gst_clapper_importer_add_allocation_metas (self->importer, query);
+  GST_CLAPPER_SINK_UNLOCK (self);
+
+  return TRUE;
+}
+
+static gboolean
+gst_clapper_sink_query (GstBaseSink *bsink, GstQuery *query)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (bsink);
+  gboolean res = FALSE;
+
+  GST_CLAPPER_SINK_LOCK (self);
+
+  if (GST_QUERY_TYPE (query) == GST_QUERY_CONTEXT) {
+    gboolean is_inactive;
+
+    GST_OBJECT_LOCK (self);
+    is_inactive = (GST_STATE (self) < GST_STATE_PAUSED);
+    GST_OBJECT_UNLOCK (self);
+
+    /* Some random context query in the middle of playback
+     * should not trigger importer replacement */
+    if (is_inactive)
+      gst_clapper_importer_loader_find_importer_for_context_query (query, &self->importer);
+    if (self->importer)
+      res = gst_clapper_importer_handle_context_query (self->importer, bsink, query);
+  }
+
+  GST_CLAPPER_SINK_UNLOCK (self);
+
+  if (res)
+    return TRUE;
+
+  return GST_BASE_SINK_CLASS (parent_class)->query (bsink, query);
+}
+
+static gboolean
+gst_clapper_sink_start_on_main (GstClapperSink *self)
+{
+  GtkWidget *widget;
+
+  GST_CLAPPER_SINK_LOCK (self);
+
+  /* Make sure widget is created */
+  if (!(widget = gst_clapper_sink_get_widget (self))) {
+    GST_CLAPPER_SINK_UNLOCK (self);
+
+    return FALSE;
+  }
+
+  /* When no toplevel window, make our own */
+  if (G_UNLIKELY (!gtk_widget_get_root (widget) && !self->window)) {
+    GtkWidget *toplevel, *parent;
+    GtkCssProvider *provider;
+    gchar *win_title;
+
+    if ((parent = gtk_widget_get_parent (widget))) {
+      GtkWidget *temp_parent;
+
+      while ((temp_parent = gtk_widget_get_parent (parent)))
+        parent = temp_parent;
+    }
+    toplevel = (parent) ? parent : widget;
+
+    self->window = (GtkWindow *) gtk_window_new ();
+    gtk_widget_add_css_class (GTK_WIDGET (self->window), WINDOW_CSS_CLASS_NAME);
+
+    provider = gtk_css_provider_new ();
+    gtk_css_provider_load_from_data (provider,
+        "." WINDOW_CSS_CLASS_NAME " { background: none; }", -1);
+    gtk_style_context_add_provider_for_display (
+        gdk_display_get_default (), GTK_STYLE_PROVIDER (provider),
+        GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+    g_object_unref (provider);
+
+    win_title = g_strdup_printf ("Clapper Sink - GTK %u.%u.%u Window",
+        gtk_get_major_version (),
+        gtk_get_minor_version (),
+        gtk_get_micro_version ());
+
+    /* Set some common default size, adding stock headerbar height
+     * to it in order to display 4:3 aspect video widget */
+    gtk_window_set_default_size (self->window, 640, 480 + 37);
+    gtk_window_set_title (self->window, win_title);
+    gtk_window_set_child (self->window, toplevel);
+
+    g_free (win_title);
+
+    self->window_destroy_id = g_signal_connect (self->window,
+        "destroy", G_CALLBACK (window_destroy_cb), self);
+  }
+
+  GST_CLAPPER_SINK_UNLOCK (self);
+
+  return TRUE;
+}
+
+static gboolean
+window_present_on_main_idle (GtkWindow *window)
+{
+  GST_INFO ("Presenting window");
+  gtk_window_present (window);
+
+  return G_SOURCE_REMOVE;
+}
+
+static gboolean
+gst_clapper_sink_start (GstBaseSink *bsink)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (bsink);
+
+  GST_INFO_OBJECT (self, "Start");
+
+  if (G_UNLIKELY (!(! !gst_gtk_invoke_on_main ((GThreadFunc) (GCallback)
+      gst_clapper_sink_start_on_main, self)))) {
+    GST_ELEMENT_ERROR (self, RESOURCE, NOT_FOUND,
+        ("GtkWidget could not be created"), (NULL));
+
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+static gboolean
+gst_clapper_sink_stop_on_main (GstClapperSink *self)
+{
+  GtkWindow *window = NULL;
+
+  GST_CLAPPER_SINK_LOCK (self);
+  if (self->window)
+    window = g_object_ref (self->window);
+  GST_CLAPPER_SINK_UNLOCK (self);
+
+  if (window) {
+    gtk_window_destroy (window);
+    g_object_unref (window);
+  }
+
+  return TRUE;
+}
+
+static gboolean
+gst_clapper_sink_stop (GstBaseSink *bsink)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (bsink);
+  gboolean has_window;
+
+  GST_INFO_OBJECT (self, "Stop");
+
+  GST_CLAPPER_SINK_LOCK (self);
+  has_window = (self->window != NULL);
+  GST_CLAPPER_SINK_UNLOCK (self);
+
+  if (G_UNLIKELY (has_window)) {
+    return (! !gst_gtk_invoke_on_main ((GThreadFunc) (GCallback)
+        gst_clapper_sink_stop_on_main, self));
+  }
+
+  return TRUE;
+}
+
+static GstStateChangeReturn
+gst_clapper_sink_change_state (GstElement *element, GstStateChange transition)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (element);
+
+  GST_DEBUG_OBJECT (self, "Changing state: %s => %s",
+      gst_element_state_get_name (GST_STATE_TRANSITION_CURRENT (transition)),
+      gst_element_state_get_name (GST_STATE_TRANSITION_NEXT (transition)));
+
+  switch (transition) {
+    case GST_STATE_CHANGE_PAUSED_TO_READY:
+      GST_CLAPPER_SINK_LOCK (self);
+      if (!self->keep_last_frame && self->importer) {
+        gst_clapper_importer_set_buffer (self->importer, NULL);
+        gst_clapper_paintable_queue_draw (self->paintable);
+      }
+      GST_CLAPPER_SINK_UNLOCK (self);
+      break;
+    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
+      GST_CLAPPER_SINK_LOCK (self);
+      if (G_UNLIKELY (self->window && !self->presented_window)) {
+        g_idle_add_full (G_PRIORITY_DEFAULT,
+            (GSourceFunc) window_present_on_main_idle,
+            g_object_ref (self->window), (GDestroyNotify) g_object_unref);
+        self->presented_window = TRUE;
+      }
+      GST_CLAPPER_SINK_UNLOCK (self);
+      break;
+    default:
+      break;
+  }
+
+  return GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
+}
+
+static void
+gst_clapper_sink_get_times (GstBaseSink *bsink, GstBuffer *buffer,
+    GstClockTime *start, GstClockTime *end)
+{
+  if (!GST_BUFFER_TIMESTAMP_IS_VALID (buffer))
+    return;
+
+  *start = GST_BUFFER_TIMESTAMP (buffer);
+
+  if (GST_BUFFER_DURATION_IS_VALID (buffer)) {
+    *end = *start + GST_BUFFER_DURATION (buffer);
+  } else {
+    GstClapperSink *self = GST_CLAPPER_SINK_CAST (bsink);
+    gint fps_n, fps_d;
+
+    GST_CLAPPER_SINK_LOCK (self);
+    fps_n = GST_VIDEO_INFO_FPS_N (&self->v_info);
+    fps_d = GST_VIDEO_INFO_FPS_D (&self->v_info);
+    GST_CLAPPER_SINK_UNLOCK (self);
+
+    if (fps_n > 0)
+      *end = *start + gst_util_uint64_scale_int (GST_SECOND, fps_d, fps_n);
+  }
+}
+
+static GstCaps *
+gst_clapper_sink_get_caps (GstBaseSink *bsink, GstCaps *filter)
+{
+  GstCaps *result, *tmp;
+
+  tmp = gst_pad_get_pad_template_caps (GST_BASE_SINK_PAD (bsink));
+
+  if (filter) {
+    GST_DEBUG ("Intersecting with filter caps: %" GST_PTR_FORMAT, filter);
+    result = gst_caps_intersect_full (filter, tmp, GST_CAPS_INTERSECT_FIRST);
+    gst_caps_unref (tmp);
+  } else {
+    result = tmp;
+  }
+  GST_DEBUG ("Returning caps: %" GST_PTR_FORMAT, result);
+
+  return result;
+}
+
+static gboolean
+gst_clapper_sink_set_caps (GstBaseSink *bsink, GstCaps *caps)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (bsink);
+
+  GST_INFO_OBJECT (self, "Set caps: %" GST_PTR_FORMAT, caps);
+  GST_CLAPPER_SINK_LOCK (self);
+
+  if (G_UNLIKELY (!self->widget)) {
+    GST_CLAPPER_SINK_UNLOCK (self);
+    GST_ELEMENT_ERROR (self, RESOURCE, NOT_FOUND,
+        ("Output widget was destroyed"), (NULL));
+
+    return FALSE;
+  }
+
+  if (!gst_clapper_importer_loader_find_importer_for_caps (caps, &self->importer)) {
+    GST_CLAPPER_SINK_UNLOCK (self);
+    GST_ELEMENT_ERROR (self, RESOURCE, NOT_FOUND,
+        ("No importer for given caps found"), (NULL));
+
+    return FALSE;
+  }
+  gst_clapper_paintable_set_importer (self->paintable, self->importer);
+
+  GST_CLAPPER_SINK_UNLOCK (self);
+
+  return GST_BASE_SINK_CLASS (parent_class)->set_caps (bsink, caps);
+}
+
+static gboolean
+gst_clapper_sink_set_info (GstVideoSink *vsink, GstCaps *caps, const GstVideoInfo *info)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (vsink);
+  gboolean res;
+
+  GST_CLAPPER_SINK_LOCK (self);
+
+  self->v_info = *info;
+  GST_DEBUG_OBJECT (self, "Video info changed");
+
+  res = gst_clapper_paintable_set_video_info (self->paintable, info);
+  GST_CLAPPER_SINK_UNLOCK (self);
+
+  return res;
+}
+
+static GstFlowReturn
+gst_clapper_sink_show_frame (GstVideoSink *vsink, GstBuffer *buffer)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (vsink);
+
+  GST_TRACE ("Got %" GST_PTR_FORMAT, buffer);
+  GST_CLAPPER_SINK_LOCK (self);
+
+  if (G_UNLIKELY (!self->widget)) {
+    GST_CLAPPER_SINK_UNLOCK (self);
+    GST_ELEMENT_ERROR (self, RESOURCE, NOT_FOUND,
+        ("Output widget was destroyed"), (NULL));
+
+    return GST_FLOW_ERROR;
+  }
+
+  gst_clapper_importer_set_buffer (self->importer, buffer);
+  gst_clapper_paintable_queue_draw (self->paintable);
+
+  GST_CLAPPER_SINK_UNLOCK (self);
+
+  return GST_FLOW_OK;
+}
+
+static void
+gst_clapper_sink_init (GstClapperSink *self)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = (GObjectClass *) GST_CLAPPER_SINK_GET_CLASS (self);
+
+  /* HACK: install here instead of class init to avoid GStreamer
+   * plugin scanner GObject type conflicts with older GTK versions */
+  if (!g_object_class_find_property (gobject_class, "widget")) {
+    g_object_class_install_property (gobject_class, PROP_WIDGET,
+        g_param_spec_object ("widget", "GTK Widget",
+            "The GtkWidget to place in the widget hierarchy",
+            GTK_TYPE_WIDGET, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+  }
+
+  self->force_aspect_ratio = DEFAULT_FORCE_ASPECT_RATIO;
+  self->par_n = DEFAULT_PAR_N;
+  self->par_d = DEFAULT_PAR_D;
+  self->keep_last_frame = DEFAULT_KEEP_LAST_FRAME;
+
+  g_mutex_init (&self->lock);
+  gst_video_info_init (&self->v_info);
+
+  self->paintable = gst_clapper_paintable_new ();
+}
+
+static void
+gst_clapper_sink_dispose (GObject *object)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (object);
+
+  GST_CLAPPER_SINK_LOCK (self);
+
+  window_clear_no_lock (self);
+  widget_clear_no_lock (self);
+
+  g_clear_object (&self->paintable);
+  gst_clear_object (&self->importer);
+
+  GST_CLAPPER_SINK_UNLOCK (self);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, dispose, (object));
+}
+
+static void
+gst_clapper_sink_finalize (GObject *object)
+{
+  GstClapperSink *self = GST_CLAPPER_SINK_CAST (object);
+
+  GST_TRACE ("Finalize");
+
+  gst_clapper_importer_loader_unload_all ();
+  g_mutex_clear (&self->lock);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
+}
+
+static void
+gst_clapper_sink_class_init (GstClapperSinkClass *klass)
+{
+  GstPadTemplate *sink_pad_templ;
+
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+  GstElementClass *gstelement_class = (GstElementClass *) klass;
+  GstBaseSinkClass *gstbasesink_class = (GstBaseSinkClass *) klass;
+  GstVideoSinkClass *gstvideosink_class = (GstVideoSinkClass *) klass;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clappersink", 0,
+      "Clapper Sink");
+
+  gobject_class->get_property = gst_clapper_sink_get_property;
+  gobject_class->set_property = gst_clapper_sink_set_property;
+  gobject_class->dispose = gst_clapper_sink_dispose;
+  gobject_class->finalize = gst_clapper_sink_finalize;
+
+  g_object_class_install_property (gobject_class, PROP_FORCE_ASPECT_RATIO,
+      g_param_spec_boolean ("force-aspect-ratio", "Force aspect ratio",
+          "When enabled, scaling will respect original aspect ratio",
+          DEFAULT_FORCE_ASPECT_RATIO,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (gobject_class, PROP_PIXEL_ASPECT_RATIO,
+      gst_param_spec_fraction ("pixel-aspect-ratio", "Pixel Aspect Ratio",
+          "The pixel aspect ratio of the device",
+          DEFAULT_PAR_N, DEFAULT_PAR_D,
+          G_MAXINT, 1, 1, 1, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (gobject_class, PROP_KEEP_LAST_FRAME,
+      g_param_spec_boolean ("keep-last-frame", "Keep last frame",
+          "Keep showing last video frame after playback instead of black screen",
+          DEFAULT_KEEP_LAST_FRAME,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  gstelement_class->change_state = gst_clapper_sink_change_state;
+
+  gstbasesink_class->get_caps = gst_clapper_sink_get_caps;
+  gstbasesink_class->set_caps = gst_clapper_sink_set_caps;
+  gstbasesink_class->get_times = gst_clapper_sink_get_times;
+  gstbasesink_class->propose_allocation = gst_clapper_sink_propose_allocation;
+  gstbasesink_class->query = gst_clapper_sink_query;
+  gstbasesink_class->start = gst_clapper_sink_start;
+  gstbasesink_class->stop = gst_clapper_sink_stop;
+
+  gstvideosink_class->set_info = gst_clapper_sink_set_info;
+  gstvideosink_class->show_frame = gst_clapper_sink_show_frame;
+
+  gst_element_class_set_metadata (gstelement_class,
+      "Clapper video sink",
+      "Sink/Video", "A GTK4 video sink used by Clapper media player",
+      "Rafał Dzięgiel <rafostar.github@gmail.com>");
+
+  sink_pad_templ = gst_clapper_importer_loader_make_sink_pad_template ();
+  gst_element_class_add_pad_template (gstelement_class, sink_pad_templ);
+}
+
+/*
+ * GstNavigationInterface
+ */
+static void
+gst_clapper_sink_navigation_interface_init (GstNavigationInterface *iface)
+{
+  /* TODO: Port to "send_event_simple" once we depend on GStreamer 1.22 */
+  iface->send_event = gst_clapper_sink_navigation_send_event;
+}

lib/gst/plugin/gstclappersink.h

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+#include <gtk/gtk.h>
+#include <gst/gst.h>
+#include <gst/video/gstvideosink.h>
+#include <gst/video/video.h>
+
+#include "gstclapperpaintable.h"
+#include "gstclapperimporter.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_SINK (gst_clapper_sink_get_type())
+G_DECLARE_FINAL_TYPE (GstClapperSink, gst_clapper_sink, GST, CLAPPER_SINK, GstVideoSink)
+
+#define GST_CLAPPER_SINK_GET_CLASS(obj)     (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_CLAPPER_SINK, GstClapperSinkClass))
+#define GST_CLAPPER_SINK_CAST(obj)          ((GstClapperSink *)(obj))
+
+#define GST_CLAPPER_SINK_GET_LOCK(obj)      (&GST_CLAPPER_SINK_CAST(obj)->lock)
+#define GST_CLAPPER_SINK_LOCK(obj)          g_mutex_lock (GST_CLAPPER_SINK_GET_LOCK(obj))
+#define GST_CLAPPER_SINK_UNLOCK(obj)        g_mutex_unlock (GST_CLAPPER_SINK_GET_LOCK(obj))
+
+struct _GstClapperSink
+{
+  GstVideoSink parent;
+
+  GMutex lock;
+
+  GstClapperPaintable *paintable;
+  GstClapperImporter *importer;
+  GstVideoInfo v_info;
+
+  GtkWidget *widget;
+  GtkWindow *window;
+
+  gboolean presented_window;
+
+  /* Properties */
+  gboolean force_aspect_ratio;
+  gint par_n, par_d;
+  gboolean keep_last_frame;
+
+  /* Position coords */
+  gdouble last_pos_x;
+  gdouble last_pos_y;
+
+  gulong widget_destroy_id;
+  gulong window_destroy_id;
+};
+
+GST_ELEMENT_REGISTER_DECLARE (clappersink);
+
+G_END_DECLS

lib/gst/plugin/gstgdkformats.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include <glib.h>
+
+#if G_BYTE_ORDER == G_LITTLE_ENDIAN
+#define GST_GDK_MEMORY_ENDIAN_FORMATS      "RGBA64_LE"
+#define GST_GDK_GL_TEXTURE_ENDIAN_FORMATS  "RGBA64_LE"
+#elif G_BYTE_ORDER == G_BIG_ENDIAN
+#define GST_GDK_MEMORY_ENDIAN_FORMATS      "RGBA64_BE"
+#define GST_GDK_GL_TEXTURE_ENDIAN_FORMATS  "RGBA64_BE"
+#endif
+
+#define GST_GDK_MEMORY_FORMATS                       \
+    GST_GDK_MEMORY_ENDIAN_FORMATS ", "               \
+    "ABGR, BGRA, ARGB, RGBA, BGRx, RGBx, BGR, RGB"
+
+/* Formats that `GdkGLTexture` supports */
+#define GST_GDK_GL_TEXTURE_FORMATS                   \
+    GST_GDK_GL_TEXTURE_ENDIAN_FORMATS ", "           \
+    "RGBA, RGBx, RGB"

lib/gst/plugin/gstgtkutils.c

@@ -0,0 +1,132 @@
+/*
+ * GStreamer
+ * Copyright (C) 2015 Matthew Waters <matthew@centricular.com>
+ * Copyright (C) 2015 Thibault Saunier <tsaunier@gnome.org>
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "gstgtkutils.h"
+
+struct invoke_context
+{
+  GThreadFunc func;
+  gpointer data;
+  GMutex lock;
+  GCond cond;
+  gboolean fired;
+
+  gpointer res;
+};
+
+static gboolean
+gst_gtk_invoke_func (struct invoke_context *info)
+{
+  g_mutex_lock (&info->lock);
+  info->res = info->func (info->data);
+  info->fired = TRUE;
+  g_cond_signal (&info->cond);
+  g_mutex_unlock (&info->lock);
+
+  return G_SOURCE_REMOVE;
+}
+
+gpointer
+gst_gtk_invoke_on_main (GThreadFunc func, gpointer data)
+{
+  GMainContext *main_context = g_main_context_default ();
+  struct invoke_context info;
+
+  g_mutex_init (&info.lock);
+  g_cond_init (&info.cond);
+  info.fired = FALSE;
+  info.func = func;
+  info.data = data;
+
+  g_main_context_invoke (main_context, (GSourceFunc) gst_gtk_invoke_func,
+      &info);
+
+  g_mutex_lock (&info.lock);
+  while (!info.fired)
+    g_cond_wait (&info.cond, &info.lock);
+  g_mutex_unlock (&info.lock);
+
+  g_mutex_clear (&info.lock);
+  g_cond_clear (&info.cond);
+
+  return info.res;
+}
+
+/* For use with `GdkMemoryTexture` only! */
+GdkMemoryFormat
+gst_video_format_to_gdk_memory_format (GstVideoFormat format)
+{
+  switch (format) {
+    case GST_VIDEO_FORMAT_RGBA64_LE:
+    case GST_VIDEO_FORMAT_RGBA64_BE:
+      return GDK_MEMORY_R16G16B16A16_PREMULTIPLIED;
+    case GST_VIDEO_FORMAT_RGBA:
+      return GDK_MEMORY_R8G8B8A8;
+    case GST_VIDEO_FORMAT_BGRA:
+      return GDK_MEMORY_B8G8R8A8;
+    case GST_VIDEO_FORMAT_ARGB:
+      return GDK_MEMORY_A8R8G8B8;
+    case GST_VIDEO_FORMAT_ABGR:
+      return GDK_MEMORY_A8B8G8R8;
+    case GST_VIDEO_FORMAT_RGBx:
+      return GDK_MEMORY_R8G8B8A8_PREMULTIPLIED;
+    case GST_VIDEO_FORMAT_BGRx:
+      return GDK_MEMORY_B8G8R8A8_PREMULTIPLIED;
+    case GST_VIDEO_FORMAT_RGB:
+      return GDK_MEMORY_R8G8B8;
+    case GST_VIDEO_FORMAT_BGR:
+      return GDK_MEMORY_B8G8R8;
+    default:
+      break;
+  }
+
+  /* This should never happen as long as above switch statement
+   * is updated when new formats are added to caps */
+  g_assert_not_reached ();
+
+  /* Fallback format */
+  return GDK_MEMORY_R8G8B8A8_PREMULTIPLIED;
+}
+
+GdkTexture *
+gst_video_frame_into_gdk_texture (GstVideoFrame *frame)
+{
+  GdkTexture *texture;
+  GBytes *bytes;
+
+  bytes = g_bytes_new_with_free_func (
+      GST_VIDEO_FRAME_PLANE_DATA (frame, 0),
+      GST_VIDEO_FRAME_HEIGHT (frame) * GST_VIDEO_FRAME_PLANE_STRIDE (frame, 0),
+      (GDestroyNotify) gst_buffer_unref,
+      gst_buffer_ref (frame->buffer));
+
+  texture = gdk_memory_texture_new (
+      GST_VIDEO_FRAME_WIDTH (frame),
+      GST_VIDEO_FRAME_HEIGHT (frame),
+      gst_video_format_to_gdk_memory_format (GST_VIDEO_FRAME_FORMAT (frame)),
+      bytes,
+      GST_VIDEO_FRAME_PLANE_STRIDE (frame, 0));
+
+  g_bytes_unref (bytes);
+
+  return texture;
+}

lib/gst/plugin/gstgtkutils.h

@@ -0,0 +1,37 @@
+/*
+ * GStreamer
+ * Copyright (C) 2015 Matthew Waters <matthew@centricular.com>
+ * Copyright (C) 2015 Thibault Saunier <tsaunier@gnome.org>
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+#include <glib.h>
+#include <gtk/gtk.h>
+#include <gst/video/video.h>
+
+G_BEGIN_DECLS
+
+gpointer        gst_gtk_invoke_on_main                (GThreadFunc func, gpointer data);
+
+GdkMemoryFormat gst_video_format_to_gdk_memory_format (GstVideoFormat format);
+
+GdkTexture *    gst_video_frame_into_gdk_texture      (GstVideoFrame *frame);
+
+G_END_DECLS

lib/gst/plugin/gstplugin.c

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gmodule.h>
+
+#include "gstclappersink.h"
+
+static gboolean
+plugin_init (GstPlugin *plugin)
+{
+  if (!g_module_supported ())
+    return FALSE;
+
+  gst_plugin_add_dependency_simple (plugin,
+      NULL, CLAPPER_SINK_IMPORTER_PATH, NULL,
+      GST_PLUGIN_DEPENDENCY_FLAG_NONE);
+
+  return GST_ELEMENT_REGISTER (clappersink, plugin);
+}
+
+GST_PLUGIN_DEFINE (GST_VERSION_MAJOR, GST_VERSION_MINOR,
+    clapper, "Clapper elements", plugin_init, VERSION, "LGPL",
+    GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN)

lib/gst/plugin/importers/gstclapperglbaseimporter.c

@@ -0,0 +1,549 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstclapperglbaseimporter.h"
+#include "gst/plugin/gstgdkformats.h"
+#include "gst/plugin/gstgtkutils.h"
+
+#include <gst/gl/gstglfuncs.h>
+
+#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WAYLAND
+#include <gdk/wayland/gdkwayland.h>
+#include <gst/gl/wayland/gstgldisplay_wayland.h>
+#endif
+
+#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11
+#include <gdk/x11/gdkx.h>
+#endif
+#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_GLX
+#include <gst/gl/x11/gstgldisplay_x11.h>
+#endif
+#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_EGL
+#include <gst/gl/egl/gstgldisplay_egl.h>
+#endif
+
+#define GST_CAT_DEFAULT gst_clapper_gl_base_importer_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+#define parent_class gst_clapper_gl_base_importer_parent_class
+G_DEFINE_TYPE (GstClapperGLBaseImporter, gst_clapper_gl_base_importer, GST_TYPE_CLAPPER_IMPORTER);
+
+static GstGLContext *
+wrap_current_gl (GstGLDisplay *display, GdkGLAPI gdk_gl_api, GstGLPlatform platform)
+{
+  GstGLAPI gst_gl_api = GST_GL_API_NONE;
+
+  switch (gdk_gl_api) {
+    case GDK_GL_API_GL:
+      gst_gl_api = GST_GL_API_OPENGL | GST_GL_API_OPENGL3;
+      break;
+    case GDK_GL_API_GLES:
+      gst_gl_api = GST_GL_API_GLES2;
+      break;
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+
+  if (gst_gl_api != GST_GL_API_NONE) {
+    guintptr gl_handle;
+
+    gst_gl_display_filter_gl_api (display, gst_gl_api);
+
+    if ((gl_handle = gst_gl_context_get_current_gl_context (platform)))
+      return gst_gl_context_new_wrapped (display, gl_handle, platform, gst_gl_api);
+  }
+
+  return NULL;
+}
+
+static gboolean
+retrieve_gl_context_on_main (GstClapperGLBaseImporter *self)
+{
+  GstClapperGLBaseImporterClass *gl_bi_class = GST_CLAPPER_GL_BASE_IMPORTER_GET_CLASS (self);
+  GdkDisplay *gdk_display;
+  GdkGLContext *gdk_context;
+  GError *error = NULL;
+  GdkGLAPI gdk_gl_api;
+  GstGLPlatform platform = GST_GL_PLATFORM_NONE;
+  gint gl_major = 0, gl_minor = 0;
+
+  if (!gtk_init_check ()) {
+    GST_ERROR_OBJECT (self, "Could not ensure GTK initialization");
+    return FALSE;
+  }
+
+  /* Make sure we are clean here, otherwise data sharing
+   * between GL-based importers may lead to leaks */
+  gst_clear_object (&self->wrapped_context);
+  g_clear_object (&self->gdk_context);
+  gst_clear_object (&self->gst_display);
+
+  gdk_display = gdk_display_get_default ();
+
+  if (!(gdk_context = gdk_display_create_gl_context (gdk_display, &error))) {
+    GST_ERROR_OBJECT (self, "Error creating Gdk GL context: %s",
+        error ? error->message : "No error set by Gdk");
+    g_clear_error (&error);
+
+    return FALSE;
+  }
+
+  if (!gl_bi_class->gdk_context_realize (self, gdk_context)) {
+    GST_ERROR_OBJECT (self, "Could not realize Gdk context: %" GST_PTR_FORMAT,
+        gdk_context);
+    g_object_unref (gdk_context);
+
+    return FALSE;
+  }
+  gdk_gl_api = gdk_gl_context_get_api (gdk_context);
+
+  GST_OBJECT_LOCK (self);
+
+  self->gdk_context = gdk_context;
+
+#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WAYLAND
+  if (GDK_IS_WAYLAND_DISPLAY (gdk_display)) {
+    struct wl_display *wayland_display =
+        gdk_wayland_display_get_wl_display (gdk_display);
+    self->gst_display = (GstGLDisplay *)
+        gst_gl_display_wayland_new_with_display (wayland_display);
+  }
+#endif
+
+#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11
+  if (GDK_IS_X11_DISPLAY (gdk_display)) {
+    gpointer display_ptr;
+#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_EGL
+    display_ptr = gdk_x11_display_get_egl_display (gdk_display);
+    if (display_ptr) {
+      self->gst_display = (GstGLDisplay *)
+          gst_gl_display_egl_new_with_egl_display (display_ptr);
+    }
+#endif
+#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_GLX
+    if (!self->gst_display) {
+      display_ptr = gdk_x11_display_get_xdisplay (gdk_display);
+      self->gst_display = (GstGLDisplay *)
+          gst_gl_display_x11_new_with_display (display_ptr);
+    }
+  }
+#endif
+#endif
+
+  /* Fallback to generic display */
+  if (G_UNLIKELY (!self->gst_display)) {
+    GST_WARNING_OBJECT (self, "Unknown Gdk display!");
+    self->gst_display = gst_gl_display_new ();
+  }
+
+#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WAYLAND
+  if (GST_IS_GL_DISPLAY_WAYLAND (self->gst_display)) {
+    platform = GST_GL_PLATFORM_EGL;
+    GST_INFO_OBJECT (self, "Using EGL on Wayland");
+    goto have_display;
+  }
+#endif
+#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_EGL
+  if (GST_IS_GL_DISPLAY_EGL (self->gst_display)) {
+    platform = GST_GL_PLATFORM_EGL;
+    GST_INFO_OBJECT (self, "Using EGL on x11");
+    goto have_display;
+  }
+#endif
+#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_GLX
+  if (GST_IS_GL_DISPLAY_X11 (self->gst_display)) {
+    platform = GST_GL_PLATFORM_GLX;
+    GST_INFO_OBJECT (self, "Using GLX on x11");
+    goto have_display;
+  }
+#endif
+
+  g_clear_object (&self->gdk_context);
+  gst_clear_object (&self->gst_display);
+
+  GST_OBJECT_UNLOCK (self);
+
+  GST_ERROR_OBJECT (self, "Unsupported GL platform");
+  return FALSE;
+
+have_display:
+  gdk_gl_context_make_current (self->gdk_context);
+
+  self->wrapped_context = wrap_current_gl (self->gst_display, gdk_gl_api, platform);
+  if (!self->wrapped_context) {
+    GST_ERROR ("Could not retrieve Gdk OpenGL context");
+    gdk_gl_context_clear_current ();
+
+    g_clear_object (&self->gdk_context);
+    gst_clear_object (&self->gst_display);
+
+    GST_OBJECT_UNLOCK (self);
+
+    return FALSE;
+  }
+
+  GST_INFO ("Retrieved Gdk OpenGL context %" GST_PTR_FORMAT, self->wrapped_context);
+  gst_gl_context_activate (self->wrapped_context, TRUE);
+
+  if (!gst_gl_context_fill_info (self->wrapped_context, &error)) {
+    GST_ERROR ("Failed to fill Gdk context info: %s", error->message);
+    g_clear_error (&error);
+
+    gst_gl_context_activate (self->wrapped_context, FALSE);
+
+    gst_clear_object (&self->wrapped_context);
+    g_clear_object (&self->gdk_context);
+    gst_clear_object (&self->gst_display);
+
+    GST_OBJECT_UNLOCK (self);
+
+    return FALSE;
+  }
+
+  gst_gl_context_get_gl_version (self->wrapped_context, &gl_major, &gl_minor);
+  GST_INFO ("Using OpenGL%s %i.%i", (gdk_gl_api == GDK_GL_API_GLES) ? " ES" : "",
+      gl_major, gl_minor);
+
+  /* Deactivate in both places */
+  gst_gl_context_activate (self->wrapped_context, FALSE);
+  gdk_gl_context_clear_current ();
+
+  GST_OBJECT_UNLOCK (self);
+
+  return TRUE;
+}
+
+static gboolean
+retrieve_gst_context (GstClapperGLBaseImporter *self)
+{
+  GstGLDisplay *gst_display = NULL;
+  GstGLContext *gst_context = NULL;
+  GError *error = NULL;
+
+  GST_OBJECT_LOCK (self);
+
+  gst_display = gst_object_ref (self->gst_display);
+
+  /* GstGLDisplay operations require display object lock to be held */
+  GST_OBJECT_LOCK (gst_display);
+
+  if (!self->gst_context) {
+    GST_TRACE_OBJECT (self, "Creating new GstGLContext");
+
+    if (!gst_gl_display_create_context (gst_display, self->wrapped_context,
+        &self->gst_context, &error)) {
+      GST_WARNING ("Could not create OpenGL context: %s",
+          error ? error->message : "Unknown");
+      g_clear_error (&error);
+
+      GST_OBJECT_UNLOCK (gst_display);
+      GST_OBJECT_UNLOCK (self);
+
+      return FALSE;
+    }
+  }
+
+  gst_context = gst_object_ref (self->gst_context);
+
+  GST_OBJECT_UNLOCK (self);
+
+  gst_gl_display_add_context (gst_display, gst_context);
+
+  GST_OBJECT_UNLOCK (gst_display);
+
+  gst_object_unref (gst_display);
+  gst_object_unref (gst_context);
+
+  return TRUE;
+}
+
+static gboolean
+gst_clapper_gl_base_importer_prepare (GstClapperImporter *importer)
+{
+  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER_CAST (importer);
+  gboolean need_invoke;
+
+  GST_OBJECT_LOCK (self);
+  need_invoke = (!self->gdk_context || !self->gst_display || !self->wrapped_context);
+  GST_OBJECT_UNLOCK (self);
+
+  if (need_invoke) {
+    if (!(! !gst_gtk_invoke_on_main ((GThreadFunc) (GCallback)
+        retrieve_gl_context_on_main, self)))
+      return FALSE;
+  }
+
+  if (!retrieve_gst_context (self))
+    return FALSE;
+
+  if (!GST_CLAPPER_IMPORTER_CLASS (parent_class)->prepare)
+    return TRUE;
+
+  return GST_CLAPPER_IMPORTER_CLASS (parent_class)->prepare (importer);
+}
+
+static void
+gst_clapper_gl_base_importer_share_data (GstClapperImporter *importer, GstClapperImporter *dest_importer)
+{
+  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER (importer);
+
+  if (GST_IS_CLAPPER_GL_BASE_IMPORTER (dest_importer)) {
+    GstClapperGLBaseImporter *dest = GST_CLAPPER_GL_BASE_IMPORTER (dest_importer);
+
+    GST_OBJECT_LOCK (self);
+    GST_OBJECT_LOCK (dest);
+
+    /* Successfully prepared GL importer should have all three */
+    if (self->gdk_context && self->gst_display && self->wrapped_context) {
+      g_clear_object (&dest->gdk_context);
+      dest->gdk_context = g_object_ref (self->gdk_context);
+
+      gst_clear_object (&dest->gst_display);
+      dest->gst_display = gst_object_ref (self->gst_display);
+
+      gst_clear_object (&dest->wrapped_context);
+      dest->wrapped_context = gst_object_ref (self->wrapped_context);
+    }
+
+    /* This context is not required, we can create it ourselves
+     * using gst_display and wrapped_context */
+    if (self->gst_context) {
+      gst_clear_object (&dest->gst_context);
+      dest->gst_context = gst_object_ref (self->gst_context);
+    }
+
+    GST_OBJECT_UNLOCK (dest);
+    GST_OBJECT_UNLOCK (self);
+  }
+
+  if (GST_CLAPPER_IMPORTER_CLASS (parent_class)->share_data)
+    GST_CLAPPER_IMPORTER_CLASS (parent_class)->share_data (importer, dest_importer);
+}
+
+static gboolean
+gst_clapper_gl_base_importer_handle_context_query (GstClapperImporter *importer,
+    GstBaseSink *bsink, GstQuery *query)
+{
+  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER_CAST (importer);
+  gboolean res;
+
+  GST_OBJECT_LOCK (self);
+  res = gst_gl_handle_context_query (GST_ELEMENT_CAST (bsink), query,
+      self->gst_display, self->gst_context, self->wrapped_context);
+  GST_OBJECT_UNLOCK (self);
+
+  return res;
+}
+
+static GstBufferPool *
+gst_clapper_gl_base_importer_create_pool (GstClapperImporter *importer, GstStructure **config)
+{
+  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER_CAST (importer);
+  GstBufferPool *pool;
+
+  GST_DEBUG_OBJECT (self, "Creating new GL buffer pool");
+
+  GST_OBJECT_LOCK (self);
+  pool = gst_gl_buffer_pool_new (self->gst_context);
+  GST_OBJECT_UNLOCK (self);
+
+  *config = gst_buffer_pool_get_config (pool);
+
+  gst_buffer_pool_config_add_option (*config, GST_BUFFER_POOL_OPTION_VIDEO_META);
+  gst_buffer_pool_config_add_option (*config, GST_BUFFER_POOL_OPTION_GL_SYNC_META);
+
+  return pool;
+}
+
+static void
+gst_clapper_gl_base_importer_add_allocation_metas (GstClapperImporter *importer, GstQuery *query)
+{
+  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER_CAST (importer);
+
+  gst_query_add_allocation_meta (query, GST_VIDEO_OVERLAY_COMPOSITION_META_API_TYPE, NULL);
+  gst_query_add_allocation_meta (query, GST_VIDEO_META_API_TYPE, NULL);
+
+  GST_OBJECT_LOCK (self);
+  if (self->gst_context->gl_vtable->FenceSync)
+    gst_query_add_allocation_meta (query, GST_GL_SYNC_META_API_TYPE, NULL);
+  GST_OBJECT_UNLOCK (self);
+}
+
+static gboolean
+gst_clapper_gl_base_importer_gdk_context_realize (GstClapperGLBaseImporter *self, GdkGLContext *gdk_context)
+{
+  GdkGLAPI allowed_apis;
+  GError *error = NULL;
+  const gchar *gl_env;
+  gboolean success;
+
+  GST_DEBUG_OBJECT (self, "Realizing GdkGLContext with default implementation");
+
+  /* Use single "GST_GL_API" env to also influence Gdk GL selection */
+  gl_env = g_getenv ("GST_GL_API");
+  allowed_apis = (!gl_env || g_str_has_prefix (gl_env, "gles"))
+      ? GDK_GL_API_GLES
+      : (g_str_has_prefix (gl_env, "opengl"))
+      ? GDK_GL_API_GL
+      : GDK_GL_API_GL | GDK_GL_API_GLES;
+
+  gdk_gl_context_set_allowed_apis (gdk_context, allowed_apis);
+  if (!(success = gdk_gl_context_realize (gdk_context, &error))) {
+    GST_WARNING_OBJECT (self, "Could not realize Gdk context with %s: %s",
+        (allowed_apis & GDK_GL_API_GL) ? "GL" : "GLES", error->message);
+    g_clear_error (&error);
+  }
+  if (!success && !gl_env) {
+    gdk_gl_context_set_allowed_apis (gdk_context, GDK_GL_API_GL);
+    if (!(success = gdk_gl_context_realize (gdk_context, &error))) {
+      GST_WARNING_OBJECT (self, "Could not realize Gdk context with GL: %s", error->message);
+      g_clear_error (&error);
+    }
+  }
+
+  return success;
+}
+
+static void
+gst_clapper_gl_base_importer_init (GstClapperGLBaseImporter *self)
+{
+}
+
+static void
+gst_clapper_gl_base_importer_finalize (GObject *object)
+{
+  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER_CAST (object);
+
+  g_clear_object (&self->gdk_context);
+
+  gst_clear_object (&self->gst_display);
+  gst_clear_object (&self->wrapped_context);
+  gst_clear_object (&self->gst_context);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
+}
+
+static void
+gst_clapper_gl_base_importer_class_init (GstClapperGLBaseImporterClass *klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+  GstClapperImporterClass *importer_class = (GstClapperImporterClass *) klass;
+  GstClapperGLBaseImporterClass *gl_bi_class = (GstClapperGLBaseImporterClass *) klass;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperglbaseimporter", 0,
+      "Clapper GL Base Importer");
+
+  gobject_class->finalize = gst_clapper_gl_base_importer_finalize;
+
+  importer_class->prepare = gst_clapper_gl_base_importer_prepare;
+  importer_class->share_data = gst_clapper_gl_base_importer_share_data;
+  importer_class->handle_context_query = gst_clapper_gl_base_importer_handle_context_query;
+  importer_class->create_pool = gst_clapper_gl_base_importer_create_pool;
+  importer_class->add_allocation_metas = gst_clapper_gl_base_importer_add_allocation_metas;
+
+  gl_bi_class->gdk_context_realize = gst_clapper_gl_base_importer_gdk_context_realize;
+}
+
+GstCaps *
+gst_clapper_gl_base_importer_make_supported_gdk_gl_caps (void)
+{
+  GstCaps *caps, *tmp;
+
+  tmp = gst_caps_from_string (
+      GST_VIDEO_CAPS_MAKE_WITH_FEATURES (GST_CAPS_FEATURE_MEMORY_GL_MEMORY,
+          "{ " GST_GDK_GL_TEXTURE_FORMATS " }") ", "
+          "texture-target = (string) { " GST_GL_TEXTURE_TARGET_2D_STR " }");
+
+  caps = gst_caps_copy (tmp);
+  gst_caps_set_features_simple (caps, gst_caps_features_new (
+      GST_CAPS_FEATURE_MEMORY_GL_MEMORY,
+      GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION, NULL));
+
+  gst_caps_append (caps, tmp);
+
+  return caps;
+}
+
+GStrv
+gst_clapper_gl_base_importer_make_gl_context_types (void)
+{
+  GStrv context_types;
+  GStrvBuilder *builder = g_strv_builder_new ();
+
+  g_strv_builder_add (builder, GST_GL_DISPLAY_CONTEXT_TYPE);
+  g_strv_builder_add (builder, "gst.gl.app_context");
+  g_strv_builder_add (builder, "gst.gl.local_context");
+
+  context_types = g_strv_builder_end (builder);
+  g_strv_builder_unref (builder);
+
+  return context_types;
+}
+
+GdkTexture *
+gst_clapper_gl_base_importer_make_gl_texture (GstClapperGLBaseImporter *self,
+    GstBuffer *buffer, GstVideoInfo *v_info)
+{
+  GdkTexture *texture;
+  GstGLSyncMeta *sync_meta;
+  GstVideoFrame frame;
+
+  if (G_UNLIKELY (!gst_video_frame_map (&frame, v_info, buffer, GST_MAP_READ | GST_MAP_GL))) {
+    GST_ERROR_OBJECT (self, "Could not map input buffer for reading");
+    return NULL;
+  }
+
+  GST_OBJECT_LOCK (self);
+
+  /* Must have context active here for both sync meta
+   * and Gdk texture format auto-detection to work */
+  gdk_gl_context_make_current (self->gdk_context);
+  gst_gl_context_activate (self->wrapped_context, TRUE);
+
+  sync_meta = gst_buffer_get_gl_sync_meta (buffer);
+
+  /* Wait for all previous OpenGL commands to complete,
+   * before we start using the input texture */
+  if (sync_meta) {
+    gst_gl_sync_meta_set_sync_point (sync_meta, self->gst_context);
+    gst_gl_sync_meta_wait (sync_meta, self->wrapped_context);
+  }
+
+  texture = gdk_gl_texture_new (
+      self->gdk_context,
+      *(guint *) GST_VIDEO_FRAME_PLANE_DATA (&frame, 0),
+      GST_VIDEO_FRAME_WIDTH (&frame),
+      GST_VIDEO_FRAME_HEIGHT (&frame),
+      (GDestroyNotify) gst_buffer_unref,
+      gst_buffer_ref (buffer));
+
+  gst_gl_context_activate (self->wrapped_context, FALSE);
+  gdk_gl_context_clear_current ();
+
+  GST_OBJECT_UNLOCK (self);
+
+  gst_video_frame_unmap (&frame);
+
+  return texture;
+}

lib/gst/plugin/importers/gstclapperglbaseimporter.h

@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+#include <gst/gl/gl.h>
+
+#include "gst/plugin/gstclapperimporter.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_GL_BASE_IMPORTER               (gst_clapper_gl_base_importer_get_type())
+#define GST_IS_CLAPPER_GL_BASE_IMPORTER(obj)            (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_CLAPPER_GL_BASE_IMPORTER))
+#define GST_IS_CLAPPER_GL_BASE_IMPORTER_CLASS(klass)    (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_CLAPPER_GL_BASE_IMPORTER))
+#define GST_CLAPPER_GL_BASE_IMPORTER_GET_CLASS(obj)     (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_CLAPPER_GL_BASE_IMPORTER, GstClapperGLBaseImporterClass))
+#define GST_CLAPPER_GL_BASE_IMPORTER(obj)               (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_CLAPPER_GL_BASE_IMPORTER, GstClapperGLBaseImporter))
+#define GST_CLAPPER_GL_BASE_IMPORTER_CLASS(klass)       (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_CLAPPER_GL_BASE_IMPORTER, GstClapperGLBaseImporterClass))
+#define GST_CLAPPER_GL_BASE_IMPORTER_CAST(obj)          ((GstClapperGLBaseImporter *)(obj))
+
+#define GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WAYLAND       (GST_GL_HAVE_WINDOW_WAYLAND && defined (GDK_WINDOWING_WAYLAND))
+#define GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11           (GST_GL_HAVE_WINDOW_X11 && defined (GDK_WINDOWING_X11))
+#define GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_GLX       (GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11 && GST_GL_HAVE_PLATFORM_GLX)
+#define GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_EGL       (GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11 && GST_GL_HAVE_PLATFORM_EGL)
+
+typedef struct _GstClapperGLBaseImporter GstClapperGLBaseImporter;
+typedef struct _GstClapperGLBaseImporterClass GstClapperGLBaseImporterClass;
+
+#ifdef G_DEFINE_AUTOPTR_CLEANUP_FUNC
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (GstClapperGLBaseImporter, gst_object_unref)
+#endif
+
+struct _GstClapperGLBaseImporter
+{
+  GstClapperImporter parent;
+
+  GdkGLContext *gdk_context;
+
+  GstGLDisplay *gst_display;
+  GstGLContext *wrapped_context;
+  GstGLContext *gst_context;
+};
+
+struct _GstClapperGLBaseImporterClass
+{
+  GstClapperImporterClass parent_class;
+
+  gboolean (* gdk_context_realize) (GstClapperGLBaseImporter *gl_bi,
+                                    GdkGLContext             *gdk_context);
+};
+
+GType        gst_clapper_gl_base_importer_get_type                   (void);
+
+GstCaps *    gst_clapper_gl_base_importer_make_supported_gdk_gl_caps (void);
+
+GStrv        gst_clapper_gl_base_importer_make_gl_context_types      (void);
+
+GdkTexture * gst_clapper_gl_base_importer_make_gl_texture            (GstClapperGLBaseImporter *self, GstBuffer *buffer, GstVideoInfo *v_info);
+
+G_END_DECLS

lib/gst/plugin/importers/gstclapperglimporter.c

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstclapperglimporter.h"
+
+#define GST_CAT_DEFAULT gst_clapper_gl_importer_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+#define parent_class gst_clapper_gl_importer_parent_class
+GST_CLAPPER_IMPORTER_DEFINE (GstClapperGLImporter, gst_clapper_gl_importer, GST_TYPE_CLAPPER_GL_BASE_IMPORTER);
+
+static GdkTexture *
+gst_clapper_gl_importer_generate_texture (GstClapperImporter *importer,
+    GstBuffer *buffer, GstVideoInfo *v_info)
+{
+  GstClapperGLBaseImporter *gl_bi = GST_CLAPPER_GL_BASE_IMPORTER_CAST (importer);
+
+  return gst_clapper_gl_base_importer_make_gl_texture (gl_bi, buffer, v_info);
+}
+
+static void
+gst_clapper_gl_importer_init (GstClapperGLImporter *self)
+{
+}
+
+static void
+gst_clapper_gl_importer_class_init (GstClapperGLImporterClass *klass)
+{
+  GstClapperImporterClass *importer_class = (GstClapperImporterClass *) klass;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperglimporter", 0,
+      "Clapper GL Importer");
+
+  importer_class->generate_texture = gst_clapper_gl_importer_generate_texture;
+}
+
+GstClapperImporter *
+make_importer (void)
+{
+  return g_object_new (GST_TYPE_CLAPPER_GL_IMPORTER, NULL);
+}
+
+GstCaps *
+make_caps (GstRank *rank, GStrv *context_types)
+{
+  *rank = GST_RANK_SECONDARY;
+  *context_types = gst_clapper_gl_base_importer_make_gl_context_types ();
+
+  return gst_clapper_gl_base_importer_make_supported_gdk_gl_caps ();
+}

lib/gst/plugin/importers/gstclapperglimporter.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+#include "gstclapperglbaseimporter.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_GL_IMPORTER (gst_clapper_gl_importer_get_type())
+G_DECLARE_FINAL_TYPE (GstClapperGLImporter, gst_clapper_gl_importer, GST, CLAPPER_GL_IMPORTER, GstClapperGLBaseImporter)
+
+#define GST_CLAPPER_GL_IMPORTER_CAST(obj)        ((GstClapperGLImporter *)(obj))
+
+struct _GstClapperGLImporter
+{
+  GstClapperGLBaseImporter parent;
+};
+
+G_END_DECLS

lib/gst/plugin/importers/gstclappergluploader.c

@@ -0,0 +1,232 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstclappergluploader.h"
+
+#define GST_CAT_DEFAULT gst_clapper_gl_uploader_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+#define parent_class gst_clapper_gl_uploader_parent_class
+GST_CLAPPER_IMPORTER_DEFINE (GstClapperGLUploader, gst_clapper_gl_uploader, GST_TYPE_CLAPPER_GL_BASE_IMPORTER);
+
+static void
+_update_elements_caps_locked (GstClapperGLUploader *self, GstCaps *upload_sink_caps)
+{
+  GstClapperGLBaseImporter *gl_bi = GST_CLAPPER_GL_BASE_IMPORTER_CAST (self);
+  GstCaps *upload_src_caps, *color_sink_caps, *color_src_caps, *gdk_sink_caps;
+
+  GST_INFO_OBJECT (self, "Input caps: %" GST_PTR_FORMAT, upload_sink_caps);
+
+  upload_src_caps = gst_gl_upload_transform_caps (self->upload, gl_bi->gst_context,
+      GST_PAD_SINK, upload_sink_caps, NULL);
+  upload_src_caps = gst_caps_fixate (upload_src_caps);
+
+  GST_INFO_OBJECT (self, "GLUpload caps: %" GST_PTR_FORMAT, upload_src_caps);
+  gst_gl_upload_set_caps (self->upload, upload_sink_caps, upload_src_caps);
+
+  gdk_sink_caps = gst_clapper_gl_base_importer_make_supported_gdk_gl_caps ();
+  color_sink_caps = gst_gl_color_convert_transform_caps (gl_bi->gst_context,
+      GST_PAD_SRC, upload_src_caps, gdk_sink_caps);
+  gst_caps_unref (gdk_sink_caps);
+
+  /* Second caps arg is transfer-full */
+  color_src_caps = gst_gl_color_convert_fixate_caps (gl_bi->gst_context,
+      GST_PAD_SINK, upload_src_caps, color_sink_caps);
+
+  GST_INFO_OBJECT (self, "GLColorConvert caps: %" GST_PTR_FORMAT, color_src_caps);
+  gst_gl_color_convert_set_caps (self->color_convert, upload_src_caps, color_src_caps);
+
+  self->has_pending_v_info = gst_video_info_from_caps (&self->pending_v_info, color_src_caps);
+
+  gst_caps_unref (upload_src_caps);
+  gst_caps_unref (color_src_caps);
+}
+
+static void
+gst_clapper_gl_uploader_set_caps (GstClapperImporter *importer, GstCaps *caps)
+{
+  GstClapperGLUploader *self = GST_CLAPPER_GL_UPLOADER_CAST (importer);
+
+  GST_OBJECT_LOCK (self);
+  _update_elements_caps_locked (self, caps);
+  GST_OBJECT_UNLOCK (self);
+}
+
+static void
+_uploader_reconfigure_locked (GstClapperGLUploader *self)
+{
+  GstCaps *in_caps = NULL;
+
+  GST_DEBUG_OBJECT (self, "Reconfiguring upload");
+
+  gst_gl_upload_get_caps (self->upload, &in_caps, NULL);
+
+  if (G_LIKELY (in_caps)) {
+    _update_elements_caps_locked (self, in_caps);
+    gst_caps_unref (in_caps);
+  }
+}
+
+static gboolean
+gst_clapper_gl_uploader_prepare (GstClapperImporter *importer)
+{
+  gboolean res = GST_CLAPPER_IMPORTER_CLASS (parent_class)->prepare (importer);
+
+  if (res) {
+    GstClapperGLUploader *self = GST_CLAPPER_GL_UPLOADER_CAST (importer);
+    GstClapperGLBaseImporter *gl_bi = GST_CLAPPER_GL_BASE_IMPORTER_CAST (importer);
+
+    GST_OBJECT_LOCK (self);
+
+    if (!self->upload)
+      self->upload = gst_gl_upload_new (gl_bi->gst_context);
+    if (!self->color_convert)
+      self->color_convert = gst_gl_color_convert_new (gl_bi->gst_context);
+
+    GST_OBJECT_UNLOCK (self);
+  }
+
+  return res;
+}
+
+static GstBuffer *
+_upload_perform_locked (GstClapperGLUploader *self, GstBuffer *buffer)
+{
+  GstBuffer *upload_buf = NULL;
+  GstGLUploadReturn ret;
+
+  ret = gst_gl_upload_perform_with_buffer (self->upload, buffer, &upload_buf);
+
+  if (G_UNLIKELY (ret != GST_GL_UPLOAD_DONE)) {
+    switch (ret) {
+      case GST_GL_UPLOAD_RECONFIGURE:
+        _uploader_reconfigure_locked (self);
+        /* Retry with the same buffer after reconfiguring */
+        return _upload_perform_locked (self, buffer);
+      default:
+        GST_ERROR_OBJECT (self, "Could not upload input buffer, returned: %i", ret);
+        break;
+    }
+  }
+
+  return upload_buf;
+}
+
+static GdkTexture *
+gst_clapper_gl_uploader_generate_texture (GstClapperImporter *importer,
+    GstBuffer *buffer, GstVideoInfo *v_info)
+{
+  GstClapperGLUploader *self = GST_CLAPPER_GL_UPLOADER_CAST (importer);
+  GstClapperGLBaseImporter *gl_bi = GST_CLAPPER_GL_BASE_IMPORTER_CAST (importer);
+  GstBuffer *upload_buf, *color_buf;
+  GdkTexture *texture;
+
+  /* XXX: We both upload and perform color conversion here, thus we skip
+   * upload for buffers that are not going to be shown and gain more free
+   * CPU time to prepare the next one. Improves performance on weak HW. */
+
+  GST_LOG_OBJECT (self, "Uploading %" GST_PTR_FORMAT, buffer);
+
+  GST_OBJECT_LOCK (self);
+
+  upload_buf = _upload_perform_locked (self, buffer);
+
+  if (G_UNLIKELY (!upload_buf)) {
+    GST_ERROR_OBJECT (self, "Could not perform upload on input buffer");
+    GST_OBJECT_UNLOCK (self);
+
+    return NULL;
+  }
+  GST_LOG_OBJECT (self, "Uploaded into %" GST_PTR_FORMAT, upload_buf);
+
+  color_buf = gst_gl_color_convert_perform (self->color_convert, upload_buf);
+  gst_buffer_unref (upload_buf);
+
+  /* Use video info associated with converted buffer */
+  if (self->has_pending_v_info) {
+    self->v_info = self->pending_v_info;
+    self->has_pending_v_info = FALSE;
+  }
+
+  GST_OBJECT_UNLOCK (self);
+
+  if (G_UNLIKELY (!color_buf)) {
+    GST_ERROR_OBJECT (self, "Could not perform color conversion on input buffer");
+    return NULL;
+  }
+  GST_LOG_OBJECT (self, "Color converted into %" GST_PTR_FORMAT, color_buf);
+
+  texture = gst_clapper_gl_base_importer_make_gl_texture (gl_bi, color_buf, &self->v_info);
+  gst_buffer_unref (color_buf);
+
+  return texture;
+}
+
+static void
+gst_clapper_gl_uploader_init (GstClapperGLUploader *self)
+{
+  gst_video_info_init (&self->pending_v_info);
+  gst_video_info_init (&self->v_info);
+}
+
+static void
+gst_clapper_gl_uploader_finalize (GObject *object)
+{
+  GstClapperGLUploader *self = GST_CLAPPER_GL_UPLOADER_CAST (object);
+
+  gst_clear_object (&self->upload);
+  gst_clear_object (&self->color_convert);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
+}
+
+static void
+gst_clapper_gl_uploader_class_init (GstClapperGLUploaderClass *klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+  GstClapperImporterClass *importer_class = (GstClapperImporterClass *) klass;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clappergluploader", 0,
+      "Clapper GL Uploader");
+
+  gobject_class->finalize = gst_clapper_gl_uploader_finalize;
+
+  importer_class->prepare = gst_clapper_gl_uploader_prepare;
+  importer_class->set_caps = gst_clapper_gl_uploader_set_caps;
+  importer_class->generate_texture = gst_clapper_gl_uploader_generate_texture;
+}
+
+GstClapperImporter *
+make_importer (void)
+{
+  return g_object_new (GST_TYPE_CLAPPER_GL_UPLOADER, NULL);
+}
+
+GstCaps *
+make_caps (GstRank *rank, GStrv *context_types)
+{
+  *rank = GST_RANK_MARGINAL + 1;
+  *context_types = gst_clapper_gl_base_importer_make_gl_context_types ();
+
+  return gst_gl_upload_get_input_template_caps ();
+}

lib/gst/plugin/importers/gstclappergluploader.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+#include "gstclapperglbaseimporter.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_GL_UPLOADER (gst_clapper_gl_uploader_get_type())
+G_DECLARE_FINAL_TYPE (GstClapperGLUploader, gst_clapper_gl_uploader, GST, CLAPPER_GL_UPLOADER, GstClapperGLBaseImporter)
+
+#define GST_CLAPPER_GL_UPLOADER_CAST(obj)        ((GstClapperGLUploader *)(obj))
+
+struct _GstClapperGLUploader
+{
+  GstClapperGLBaseImporter parent;
+
+  GstGLUpload *upload;
+  GstGLColorConvert *color_convert;
+
+  GstVideoInfo pending_v_info, v_info;
+  gboolean has_pending_v_info;
+};
+
+G_END_DECLS

lib/gst/plugin/importers/gstclapperrawimporter.c

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstclapperrawimporter.h"
+#include "gst/plugin/gstgtkutils.h"
+#include "gst/plugin/gstgdkformats.h"
+
+#define GST_CAT_DEFAULT gst_clapper_raw_importer_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+#define parent_class gst_clapper_raw_importer_parent_class
+GST_CLAPPER_IMPORTER_DEFINE (GstClapperRawImporter, gst_clapper_raw_importer, GST_TYPE_CLAPPER_IMPORTER);
+
+static GstBufferPool *
+gst_clapper_raw_importer_create_pool (GstClapperImporter *importer, GstStructure **config)
+{
+  GstClapperRawImporter *self = GST_CLAPPER_RAW_IMPORTER_CAST (importer);
+  GstBufferPool *pool;
+
+  GST_DEBUG_OBJECT (self, "Creating new buffer pool");
+
+  pool = gst_video_buffer_pool_new ();
+  *config = gst_buffer_pool_get_config (pool);
+
+  gst_buffer_pool_config_add_option (*config, GST_BUFFER_POOL_OPTION_VIDEO_META);
+
+  return pool;
+}
+
+static void
+gst_clapper_raw_importer_add_allocation_metas (GstClapperImporter *importer, GstQuery *query)
+{
+  gst_query_add_allocation_meta (query, GST_VIDEO_OVERLAY_COMPOSITION_META_API_TYPE, NULL);
+  gst_query_add_allocation_meta (query, GST_VIDEO_META_API_TYPE, NULL);
+}
+
+static GdkTexture *
+gst_clapper_raw_importer_generate_texture (GstClapperImporter *importer,
+    GstBuffer *buffer, GstVideoInfo *v_info)
+{
+  GdkTexture *texture;
+  GstVideoFrame frame;
+
+  if (G_UNLIKELY (!gst_video_frame_map (&frame, v_info, buffer, GST_MAP_READ))) {
+    GST_ERROR_OBJECT (importer, "Could not map input buffer for reading");
+    return NULL;
+  }
+
+  texture = gst_video_frame_into_gdk_texture (&frame);
+  gst_video_frame_unmap (&frame);
+
+  return texture;
+}
+
+static void
+gst_clapper_raw_importer_init (GstClapperRawImporter *self)
+{
+}
+
+static void
+gst_clapper_raw_importer_class_init (GstClapperRawImporterClass *klass)
+{
+  GstClapperImporterClass *importer_class = (GstClapperImporterClass *) klass;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperrawimporter", 0,
+      "Clapper RAW Importer");
+
+  importer_class->create_pool = gst_clapper_raw_importer_create_pool;
+  importer_class->add_allocation_metas = gst_clapper_raw_importer_add_allocation_metas;
+  importer_class->generate_texture = gst_clapper_raw_importer_generate_texture;
+}
+
+GstClapperImporter *
+make_importer (void)
+{
+  return g_object_new (GST_TYPE_CLAPPER_RAW_IMPORTER, NULL);
+}
+
+GstCaps *
+make_caps (GstRank *rank, GStrv *context_types)
+{
+  *rank = GST_RANK_MARGINAL;
+
+  return gst_caps_from_string (
+      GST_VIDEO_CAPS_MAKE_WITH_FEATURES (GST_CAPS_FEATURE_MEMORY_SYSTEM_MEMORY ", "
+          GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION,
+          "{ " GST_GDK_MEMORY_FORMATS " }")
+      "; "
+      GST_VIDEO_CAPS_MAKE (
+          "{ " GST_GDK_MEMORY_FORMATS " }"));
+}

lib/gst/plugin/importers/gstclapperrawimporter.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#pragma once
+
+#include "gst/plugin/gstclapperimporter.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_RAW_IMPORTER (gst_clapper_raw_importer_get_type())
+G_DECLARE_FINAL_TYPE (GstClapperRawImporter, gst_clapper_raw_importer, GST, CLAPPER_RAW_IMPORTER, GstClapperImporter)
+
+#define GST_CLAPPER_RAW_IMPORTER_CAST(obj)        ((GstClapperRawImporter *)(obj))
+
+struct _GstClapperRawImporter
+{
+  GstClapperImporter parent;
+};
+
+G_END_DECLS

lib/gst/plugin/importers/meson.build

@@ -0,0 +1,120 @@
+gst_clapper_gl_base_importer_dep = dependency('', required: false)
+
+plugin_needs_gl_base = (
+  not get_option('glimporter').disabled()
+  or not get_option('gluploader').disabled()
+)
+plugin_gl_support_required = (
+  get_option('glimporter').enabled()
+  or get_option('gluploader').enabled()
+)
+
+gst_plugin_gl_deps = [gstgl_dep, gstglproto_dep]
+have_gtk_gl_windowing = false
+
+if gst_gl_have_window_x11 and (gst_gl_have_platform_egl or gst_gl_have_platform_glx)
+  gtk_x11_dep = dependency('gtk4-x11', required: false)
+  if gtk_x11_dep.found()
+    gst_plugin_gl_deps += gtk_x11_dep
+    if gst_gl_have_platform_glx
+      gst_plugin_gl_deps += gstglx11_dep
+    endif
+    have_gtk_gl_windowing = true
+  endif
+endif
+
+if gst_gl_have_window_wayland and gst_gl_have_platform_egl
+  gtk_wayland_dep = dependency('gtk4-wayland', required: false)
+  if gtk_wayland_dep.found()
+    gst_plugin_gl_deps += [gtk_wayland_dep, gstglwayland_dep]
+    have_gtk_gl_windowing = true
+  endif
+endif
+
+if plugin_gl_support_required and not have_gtk_gl_windowing
+  error('GL-based importer was enabled, but support for current GL windowing is missing')
+endif
+
+if gst_gl_have_platform_egl
+  gst_plugin_gl_deps += gstglegl_dep
+endif
+
+gst_clapper_gl_base_importer_deps = [
+  gst_clapper_sink_dep
+] + gst_plugin_gl_deps
+
+foreach dep : gst_clapper_gl_base_importer_deps
+  if not dep.found()
+    if plugin_gl_support_required
+      error('GL-based importer was enabled, but required dependencies were not found')
+    endif
+    plugin_needs_gl_base = false
+  endif
+endforeach
+
+if plugin_needs_gl_base
+  gst_clapper_gl_base_importer_dep = declare_dependency(
+    link_with: library('gstclapperglbaseimporter',
+      'gstclapperglbaseimporter.c',
+      c_args: gst_clapper_plugin_args,
+      include_directories: configinc,
+      dependencies: gst_clapper_gl_base_importer_deps,
+      version: libversion,
+      install: true,
+    ),
+    include_directories: configinc,
+    dependencies: gst_clapper_gl_base_importer_deps,
+  )
+endif
+
+build_glimporter = (
+  not get_option('glimporter').disabled()
+  and gst_clapper_gl_base_importer_dep.found()
+)
+
+if build_glimporter
+  library(
+    'gstclapperglimporter',
+    'gstclapperglimporter.c',
+    dependencies: gst_clapper_gl_base_importer_dep,
+    include_directories: configinc,
+    c_args: gst_clapper_plugin_args,
+    install: true,
+    install_dir: gst_clapper_importers_libdir,
+  )
+endif
+
+build_gluploader = (
+  not get_option('gluploader').disabled()
+  and gst_clapper_gl_base_importer_dep.found()
+)
+
+if build_gluploader
+  library(
+    'gstclappergluploader',
+    'gstclappergluploader.c',
+    dependencies: gst_clapper_gl_base_importer_dep,
+    include_directories: configinc,
+    c_args: gst_clapper_plugin_args,
+    install: true,
+    install_dir: gst_clapper_importers_libdir,
+  )
+endif
+
+# No need to auto build rawimporter if we are building gluploader
+build_rawimporter = (
+  not get_option('rawimporter').disabled()
+  and (not build_gluploader or get_option('rawimporter').enabled())
+)
+
+if build_rawimporter
+  library(
+    'gstclapperrawimporter',
+    'gstclapperrawimporter.c',
+    dependencies: gst_clapper_sink_dep,
+    include_directories: configinc,
+    c_args: gst_clapper_plugin_args,
+    install: true,
+    install_dir: gst_clapper_importers_libdir,
+  )
+endif

lib/gst/plugin/meson.build

@@ -0,0 +1,72 @@
+gst_plugins_libdir = join_paths(prefix, libdir, 'gstreamer-1.0')
+
+gst_clapper_plugin_args = [
+  '-DHAVE_CONFIG_H',
+  '-DGST_USE_UNSTABLE_API',
+]
+gtk4_dep = dependency('gtk4', version: '>=4.6.0', required: false)
+
+gmodule_dep = dependency('gmodule-2.0',
+  version: glib_req,
+  required: false,
+  fallback: ['glib', 'libgmodule_dep'],
+)
+
+gst_clapper_plugin_deps = [
+  gtk4_dep,
+  gst_dep,
+  gstbase_dep,
+  gstvideo_dep,
+  gmodule_dep,
+]
+
+foreach dep : gst_clapper_plugin_deps
+  if not dep.found()
+    if gst_clapper_plugin_option.enabled()
+      error('GStreamer plugin was enabled, but required dependencies were not found')
+    endif
+    subdir_done()
+  endif
+endforeach
+
+if get_option('default_library') == 'static'
+  gst_clapper_plugin_args += ['-DGST_STATIC_COMPILATION']
+endif
+
+gst_clapper_plugin_option = get_option('gst-plugin')
+if gst_clapper_plugin_option.disabled()
+  subdir_done()
+endif
+
+foreach dep : gst_clapper_plugin_deps
+  if not dep.found()
+    if gst_clapper_plugin_option.enabled()
+      error('GStreamer plugin was enabled, but required dependencies were not found')
+    endif
+    subdir_done()
+  endif
+endforeach
+
+gst_clapper_plugin_sources = [
+  'gstclappersink.c',
+  'gstclapperpaintable.c',
+  'gstgtkutils.c',
+  'gstplugin.c',
+  'gstclapperimporter.c',
+  'gstclapperimporterloader.c',
+]
+
+gst_clapper_sink_dep = declare_dependency(
+  link_with: library('gstclapper',
+    gst_clapper_plugin_sources,
+    c_args: gst_clapper_plugin_args,
+    include_directories: configinc,
+    dependencies: gst_clapper_plugin_deps,
+    install: true,
+    install_dir: gst_plugins_libdir,
+  ),
+  include_directories: configinc,
+  dependencies: gst_clapper_plugin_deps,
+)
+
+subdir('importers')

lib/meson.build

@@ -1,5 +1,5 @@
-glib_req = '>= 2.56.0'
+glib_req = '>= 2.68.0'
-gst_req = '>= 1.18.0'
+gst_req = '>= 1.20.0'
 
 api_version = '1.0'
 libversion = meson.project_version()
@@ -42,10 +42,6 @@ endif
 # Symbol visibility
 if cc.get_id() == 'msvc'
   export_define = '__declspec(dllexport) extern'
-elif cc.has_argument('-fvisibility=hidden')
-  add_project_arguments('-fvisibility=hidden', language: 'c')
-  add_project_arguments('-fvisibility=hidden', language: 'cpp')
-  export_define = 'extern __attribute__ ((visibility ("default")))'
 else
   export_define = 'extern'
 endif
@@ -132,7 +128,7 @@ cdata.set('SIZEOF_SHORT', cc.sizeof('short'))
 cdata.set('SIZEOF_VOIDP', cc.sizeof('void*'))
 
 cdata.set_quoted('VERSION', libversion)
-cdata.set_quoted('PACKAGE', 'gst-plugins-clapper')
+cdata.set_quoted('PACKAGE', 'clapper')
 cdata.set_quoted('PACKAGE_VERSION', libversion)
 cdata.set_quoted('PACKAGE_BUGREPORT', 'https://github.com/Rafostar/clapper/issues/new')
 cdata.set_quoted('PACKAGE_NAME', 'GStreamer Clapper Libs')
@@ -184,7 +180,7 @@ foreach extra_arg : warning_flags
   endif
 endforeach
 
-cdata.set_quoted('GST_PACKAGE_NAME', 'GStreamer Plugins Clapper')
+cdata.set_quoted('GST_PACKAGE_NAME', 'gst-plugin-clapper')
 cdata.set_quoted('GST_PACKAGE_ORIGIN', 'https://github.com/Rafostar/clapper')
 
 # Mandatory GST deps
@@ -251,21 +247,21 @@ giounix_dep = dependency('gio-unix-2.0', version: glib_req, fallback: ['glib', '
 
 cdata.set('DISABLE_ORC', 1)
 cdata.set('GST_ENABLE_EXTRA_CHECKS', get_option('devel-checks'))
-cdata.set_quoted('GST_PACKAGE_RELEASE_DATETIME', 'Unknown')
 
 configinc = include_directories('.')
 libsinc = include_directories('gst')
 
-gir = find_program('g-ir-scanner', required: true)
+gir = find_program('g-ir-scanner')
-if not gir.found()
-  error('Clapper requires GI bindings to be compiled')
-endif
-
 gir_init_section = ['--add-init-section=extern void gst_init(gint*,gchar**);' + \
     'g_setenv("GST_REGISTRY_1.0", "@0@", TRUE);'.format(meson.current_build_dir() + '/gir_empty_registry.reg') + \
     'g_setenv("GST_PLUGIN_PATH_1_0", "", TRUE);' + \
     'g_setenv("GST_PLUGIN_SYSTEM_PATH_1_0", "", TRUE);' + \
     'gst_init(NULL,NULL);', '--quiet'
 ]
+
+gst_clapper_plugin_libdir = join_paths(get_option('prefix'), libdir, 'clapper-0.0', 'gst', 'plugin')
+gst_clapper_importers_libdir = join_paths(gst_clapper_plugin_libdir, 'importers')
+cdata.set_quoted('CLAPPER_SINK_IMPORTER_PATH', gst_clapper_importers_libdir)
+
 subdir('gst')
 configure_file(output: 'config.h', configuration: cdata)

meson.build

@@ -19,9 +19,7 @@ datadir = join_paths(get_option('prefix'), get_option('datadir'))
 pkglibdir = join_paths(libdir, meson.project_name())
 pkgdatadir = join_paths(datadir, meson.project_name())
 
-if get_option('lib')
+subdir('lib')
-  subdir('lib')
-endif
 
 if get_option('player')
   subdir('bin')

meson_options.txt

@@ -8,6 +8,28 @@ option('lib',
   value: true,
   description: 'Build GstClapper lib'
 )
+option('gst-plugin',
+  type: 'feature',
+  value: 'enabled',
+  description: 'Build GStreamer plugin (includes GTK video sink element)'
+)
+
+option('rawimporter',
+  type: 'feature',
+  value: 'auto',
+  description: 'Build RAW system memory importer for clappersink'
+)
+option('glimporter',
+  type: 'feature',
+  value: 'auto',
+  description: 'Build GL memory importer for clappersink'
+)
+option('gluploader',
+  type: 'feature',
+  value: 'auto',
+  description: 'Build GL uploader for clappersink'
+)
+
 option('devel-checks',
   type: 'boolean',
   value: false,

src/player.js

@@ -1,4 +1,4 @@
-const { Adw, Gdk, Gio, GObject, Gst, GstClapper, Gtk } = imports.gi;
+const { Adw, Gdk, Gio, GLib, GObject, Gst, GstClapper, Gtk } = imports.gi;
 const ByteArray = imports.byteArray;
 const Debug = imports.src.debug;
 const Misc = imports.src.misc;
@@ -16,14 +16,28 @@ class ClapperPlayer extends GstClapper.Clapper
 {
     _init()
     {
+        let vsink = null;
+        const use_legacy_sink = GLib.getenv('CLAPPER_USE_LEGACY_SINK');
+
+        if(!use_legacy_sink || use_legacy_sink != '1') {
+            vsink = Gst.ElementFactory.make('clappersink', null);
+            this.clappersink = vsink;
+        }
+
+        if(!vsink) {
+            vsink = Gst.ElementFactory.make('glsinkbin', null);
             const gtk4plugin = new GstClapper.ClapperGtk4Plugin();
-        const glsinkbin = Gst.ElementFactory.make('glsinkbin', null);
+
-        glsinkbin.sink = gtk4plugin.video_sink;
+            warn('using legacy video sink');
+
+            this.clappersink = gtk4plugin.video_sink;
+            vsink.sink = this.clappersink;
+        }
 
         super._init({
             signal_dispatcher: new GstClapper.ClapperGMainContextSignalDispatcher(),
             video_renderer: new GstClapper.ClapperVideoOverlayVideoRenderer({
-                video_sink: glsinkbin,
+                video_sink: vsink,
             }),
             mpris: new GstClapper.ClapperMpris({
                 own_name: `org.mpris.MediaPlayer2.${Misc.appName}`,
@@ -36,7 +50,7 @@ class ClapperPlayer extends GstClapper.Clapper
             use_pipewire: settings.get_boolean('use-pipewire'),
         });
 
-        this.widget = gtk4plugin.video_sink.widget;
+        this.widget = this.clappersink.widget;
         this.widget.add_css_class('videowidget');
 
         this.visualization_enabled = false;
@@ -615,7 +629,7 @@ class ClapperPlayer extends GstClapper.Clapper
 
         switch(key) {
             case 'after-playback':
-                this.widget.keep_last_frame = (settings.get_int(key) === 1);
+                this.clappersink.keep_last_frame = (settings.get_int(key) === 1);
                 break;
             case 'seeking-mode':
                 switch(settings.get_int(key)) {