Use new "clappersink" element

Use brand new clapper video sink for video output. Also add "CLAPPER_USE_LEGACY_SINK" env
to still allow the usage of old video sink if any problems arise.

lib/gst/clapper/meson.build

@@ -34,36 +34,13 @@ gstclapper_defines = [
   '-DGST_USE_UNSTABLE_API',
   '-DHAVE_GTK_GL',
 ]
-gtk_deps = [gstgl_dep, gstglproto_dep]
-have_gtk_gl_windowing = false
 
-gtk4_dep = dependency('gtk4', required: true)
-
-if not gtk4_dep.version().version_compare('>=4.0.0')
-  error('GTK4 version on this system is too old')
+if not get_option('lib')
+  subdir_done()
 endif
 
-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()
-    gtk_deps += gtk_x11_dep
-    if gst_gl_have_platform_glx
-      gtk_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()
-    gtk_deps += [gtk_wayland_dep, gstglwayland_dep]
-    have_gtk_gl_windowing = true
-  endif
-endif
-
-if gst_gl_have_platform_egl
-  gtk_deps += gstglegl_dep
+if not gir.found()
+  error('Clapper lib requires GI bindings to be compiled')
 endif
 
 if not have_gtk_gl_windowing

lib/gst/meson.build

@@ -1 +1,2 @@
 subdir('clapper')
+subdir('plugin')

lib/gst/plugin/gstclapperbaseimport.c

@@ -0,0 +1,374 @@
+/*
+ * 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 "gstclapperbaseimport.h"
+#include "gstclappergdkmemory.h"
+#include "gstclappergdkbufferpool.h"
+
+#define GST_CAT_DEFAULT gst_clapper_base_import_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+#define parent_class gst_clapper_base_import_parent_class
+G_DEFINE_TYPE (GstClapperBaseImport, gst_clapper_base_import, GST_TYPE_BASE_TRANSFORM);
+
+static void
+gst_clapper_base_import_init (GstClapperBaseImport *self)
+{
+  g_mutex_init (&self->lock);
+
+  gst_video_info_init (&self->in_info);
+  gst_video_info_init (&self->out_info);
+}
+
+static void
+gst_clapper_base_import_finalize (GObject *object)
+{
+  GstClapperBaseImport *self = GST_CLAPPER_BASE_IMPORT_CAST (object);
+
+  GST_TRACE ("Finalize");
+  g_mutex_clear (&self->lock);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
+}
+
+static GstStateChangeReturn
+gst_clapper_base_import_change_state (GstElement *element, GstStateChange transition)
+{
+  GST_DEBUG_OBJECT (element, "Changing state: %s => %s",
+      gst_element_state_get_name (GST_STATE_TRANSITION_CURRENT (transition)),
+      gst_element_state_get_name (GST_STATE_TRANSITION_NEXT (transition)));
+
+  return GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
+}
+
+static gboolean
+gst_clapper_base_import_start (GstBaseTransform *bt)
+{
+  GST_INFO_OBJECT (bt, "Start");
+
+  return TRUE;
+}
+
+static gboolean
+gst_clapper_base_import_stop (GstBaseTransform *bt)
+{
+  GST_INFO_OBJECT (bt, "Stop");
+
+  return TRUE;
+}
+
+static GstCaps *
+gst_clapper_base_import_transform_caps (GstBaseTransform *bt,
+    GstPadDirection direction, GstCaps *caps, GstCaps *filter)
+{
+  GstCaps *result, *tmp;
+
+  tmp = (direction == GST_PAD_SINK)
+      ? gst_pad_get_pad_template_caps (GST_BASE_TRANSFORM_SRC_PAD (bt))
+      : gst_pad_get_pad_template_caps (GST_BASE_TRANSFORM_SINK_PAD (bt));
+
+  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 %s caps: %" GST_PTR_FORMAT,
+      (direction == GST_PAD_SINK) ? "src" : "sink", result);
+
+  return result;
+}
+
+static gboolean
+_structure_filter_cb (GQuark field_id, GValue *value,
+    G_GNUC_UNUSED gpointer user_data)
+{
+  const gchar *str = g_quark_to_string (field_id);
+
+  if (!strcmp (str, "format")
+      || !strcmp (str, "width")
+      || !strcmp (str, "height")
+      || !strcmp (str, "pixel-aspect-ratio")
+      || !strcmp (str, "framerate"))
+    return TRUE;
+
+  return FALSE;
+}
+
+static GstCaps *
+gst_clapper_base_import_fixate_caps (GstBaseTransform *bt,
+    GstPadDirection direction, GstCaps *caps, GstCaps *othercaps)
+{
+  GstCaps *fixated;
+
+  fixated = (!gst_caps_is_any (caps))
+      ? gst_caps_fixate (gst_caps_ref (caps))
+      : gst_caps_copy (caps);
+
+  if (direction == GST_PAD_SINK) {
+    guint i, n = gst_caps_get_size (fixated);
+
+    for (i = 0; i < n; i++) {
+      GstCapsFeatures *features;
+      GstStructure *structure;
+      gboolean had_overlay_comp;
+
+      features = gst_caps_get_features (fixated, i);
+      had_overlay_comp = gst_caps_features_contains (features,
+          GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION);
+
+      features = gst_caps_features_new (GST_CAPS_FEATURE_CLAPPER_GDK_MEMORY, NULL);
+      if (had_overlay_comp)
+        gst_caps_features_add (features, GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION);
+
+      gst_caps_set_features (fixated, i, features);
+
+      /* Remove fields that do not apply to our memory */
+      if ((structure = gst_caps_get_structure (fixated, i))) {
+        gst_structure_filter_and_map_in_place (structure,
+            (GstStructureFilterMapFunc) _structure_filter_cb, NULL);
+      }
+    }
+  }
+  GST_DEBUG ("Fixated %s caps: %" GST_PTR_FORMAT,
+      (direction == GST_PAD_SRC) ? "sink" : "src", fixated);
+
+  return fixated;
+}
+
+static gboolean
+gst_clapper_base_import_set_caps (GstBaseTransform *bt,
+    GstCaps *incaps, GstCaps *outcaps)
+{
+  GstClapperBaseImport *self = GST_CLAPPER_BASE_IMPORT_CAST (bt);
+  gboolean has_sink_info, has_src_info;
+
+  if ((has_sink_info = gst_video_info_from_caps (&self->in_info, incaps)))
+    GST_INFO_OBJECT (self, "Set sink caps: %" GST_PTR_FORMAT, incaps);
+  if ((has_src_info = gst_video_info_from_caps (&self->out_info, outcaps)))
+    GST_INFO_OBJECT (self, "Set src caps: %" GST_PTR_FORMAT, outcaps);
+
+  return (has_sink_info && has_src_info);
+}
+
+static gboolean
+gst_clapper_base_import_import_propose_allocation (GstBaseTransform *bt,
+    GstQuery *decide_query, GstQuery *query)
+{
+  GstClapperBaseImport *self = GST_CLAPPER_BASE_IMPORT_CAST (bt);
+  GstClapperBaseImportClass *bi_class = GST_CLAPPER_BASE_IMPORT_GET_CLASS (self);
+  GstBufferPool *pool = NULL;
+  GstCaps *caps;
+  GstVideoInfo info;
+  guint size;
+  gboolean need_pool;
+
+  if (!GST_BASE_TRANSFORM_CLASS (parent_class)->propose_allocation (bt,
+      decide_query, query))
+    return FALSE;
+
+  /* Passthrough, nothing to do */
+  if (!decide_query)
+    return TRUE;
+
+  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);
+
+  if (need_pool) {
+    GstStructure *config = NULL;
+
+    GST_DEBUG_OBJECT (self, "Need to create upstream pool");
+    pool = bi_class->create_upstream_pool (self, &config);
+
+    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, 2, 0);
+
+      if (!gst_buffer_pool_set_config (pool, config)) {
+        gst_object_unref (pool);
+
+        GST_DEBUG_OBJECT (self, "Failed to set config");
+        return FALSE;
+      }
+    } else if (config) {
+      GST_WARNING_OBJECT (self, "Got pool config without a pool to apply it!");
+      gst_structure_free (config);
+    }
+  }
+
+  gst_query_add_allocation_pool (query, pool, size, 2, 0);
+  if (pool)
+    gst_object_unref (pool);
+
+  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);
+
+  return TRUE;
+}
+
+static gboolean
+gst_clapper_base_import_decide_allocation (GstBaseTransform *bt, GstQuery *query)
+{
+  GstClapperBaseImport *self = GST_CLAPPER_BASE_IMPORT_CAST (bt);
+  GstBufferPool *pool = NULL;
+  GstCaps *caps;
+  GstVideoInfo info;
+  guint size = 0, min = 0, max = 0;
+  gboolean update_pool, need_pool = TRUE;
+
+  gst_query_parse_allocation (query, &caps, NULL);
+
+  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;
+  }
+
+  if ((update_pool = gst_query_get_n_allocation_pools (query) > 0)) {
+    gst_query_parse_nth_allocation_pool (query, 0, &pool, &size, &min, &max);
+    if (pool) {
+      if ((need_pool = !GST_IS_CLAPPER_GDK_BUFFER_POOL (pool)))
+        gst_clear_object (&pool);
+    }
+  } else {
+    size = GST_VIDEO_INFO_SIZE (&info);
+  }
+
+  if (need_pool) {
+    GstStructure *config;
+
+    GST_DEBUG_OBJECT (self, "Creating new downstream pool");
+
+    pool = gst_clapper_gdk_buffer_pool_new ();
+    config = gst_buffer_pool_get_config (pool);
+
+    gst_buffer_pool_config_add_option (config, GST_BUFFER_POOL_OPTION_VIDEO_META);
+    gst_buffer_pool_config_set_params (config, caps, size, min, max);
+
+    if (!gst_buffer_pool_set_config (pool, config)) {
+      gst_object_unref (pool);
+
+      GST_DEBUG_OBJECT (self, "Failed to set config");
+      return FALSE;
+    }
+  }
+
+  if (update_pool)
+    gst_query_set_nth_allocation_pool (query, 0, pool, size, min, max);
+  else
+    gst_query_add_allocation_pool (query, pool, size, min, max);
+
+  if (pool)
+    gst_object_unref (pool);
+
+  return GST_BASE_TRANSFORM_CLASS (parent_class)->decide_allocation (bt, query);
+}
+
+static GstBufferPool *
+gst_clapper_base_import_create_upstream_pool (GstClapperBaseImport *self, GstStructure **config)
+{
+  GST_FIXME_OBJECT (self, "Need to create upstream buffer pool");
+
+  return NULL;
+}
+
+static void
+gst_clapper_base_import_class_init (GstClapperBaseImportClass *klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+  GstElementClass *gstelement_class = (GstElementClass *) klass;
+  GstBaseTransformClass *gstbasetransform_class = (GstBaseTransformClass *) klass;
+  GstClapperBaseImportClass *bi_class = (GstClapperBaseImportClass *) klass;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperbaseimport", 0,
+      "Clapper Base Import");
+
+  gobject_class->finalize = gst_clapper_base_import_finalize;
+
+  gstelement_class->change_state = gst_clapper_base_import_change_state;
+
+  gstbasetransform_class->passthrough_on_same_caps = TRUE;
+  gstbasetransform_class->transform_ip_on_passthrough = FALSE;
+  gstbasetransform_class->start = gst_clapper_base_import_start;
+  gstbasetransform_class->stop = gst_clapper_base_import_stop;
+  gstbasetransform_class->transform_caps = gst_clapper_base_import_transform_caps;
+  gstbasetransform_class->fixate_caps = gst_clapper_base_import_fixate_caps;
+  gstbasetransform_class->set_caps = gst_clapper_base_import_set_caps;
+  gstbasetransform_class->propose_allocation = gst_clapper_base_import_import_propose_allocation;
+  gstbasetransform_class->decide_allocation = gst_clapper_base_import_decide_allocation;
+
+  bi_class->create_upstream_pool = gst_clapper_base_import_create_upstream_pool;
+}
+
+/*
+ * Maps input video frame and output memory from in/out buffers
+ * using flags passed to this method.
+ *
+ * Remember to unmap both using `gst_video_frame_unmap` and
+ * `gst_memory_unmap` when done with the data.
+ */
+gboolean
+gst_clapper_base_import_map_buffers (GstClapperBaseImport *self,
+    GstBuffer *in_buf, GstBuffer *out_buf, GstMapFlags in_flags, GstMapFlags out_flags,
+    GstVideoFrame *frame, GstMapInfo *info, GstMemory **mem)
+{
+  GST_LOG_OBJECT (self, "Transforming from %" GST_PTR_FORMAT
+      " into %" GST_PTR_FORMAT, in_buf, out_buf);
+
+  if (G_UNLIKELY (!gst_video_frame_map (frame, &self->in_info, in_buf, in_flags))) {
+    GST_ERROR_OBJECT (self, "Could not map input buffer for reading");
+    return FALSE;
+  }
+
+  *mem = gst_buffer_peek_memory (out_buf, 0);
+
+  if (G_UNLIKELY (!gst_memory_map (*mem, info, out_flags))) {
+    GST_ERROR_OBJECT (self, "Could not map output memory for writing");
+    gst_video_frame_unmap (frame);
+
+    return FALSE;
+  }
+
+  return TRUE;
+}

lib/gst/plugin/gstclapperbaseimport.h

@@ -0,0 +1,69 @@
+/*
+ * 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/base/gstbasetransform.h>
+#include <gst/video/video.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_BASE_IMPORT               (gst_clapper_base_import_get_type())
+#define GST_IS_CLAPPER_BASE_IMPORT(obj)            (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_CLAPPER_BASE_IMPORT))
+#define GST_IS_CLAPPER_BASE_IMPORT_CLASS(klass)    (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_CLAPPER_BASE_IMPORT))
+#define GST_CLAPPER_BASE_IMPORT_GET_CLASS(obj)     (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_CLAPPER_BASE_IMPORT, GstClapperBaseImportClass))
+#define GST_CLAPPER_BASE_IMPORT(obj)               (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_CLAPPER_BASE_IMPORT, GstClapperBaseImport))
+#define GST_CLAPPER_BASE_IMPORT_CLASS(klass)       (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_CLAPPER_BASE_IMPORT, GstClapperBaseImportClass))
+#define GST_CLAPPER_BASE_IMPORT_CAST(obj)          ((GstClapperBaseImport *)(obj))
+
+#define GST_CLAPPER_BASE_IMPORT_GET_LOCK(obj)      (&GST_CLAPPER_BASE_IMPORT_CAST(obj)->lock)
+#define GST_CLAPPER_BASE_IMPORT_LOCK(obj)          g_mutex_lock (GST_CLAPPER_BASE_IMPORT_GET_LOCK(obj))
+#define GST_CLAPPER_BASE_IMPORT_UNLOCK(obj)        g_mutex_unlock (GST_CLAPPER_BASE_IMPORT_GET_LOCK(obj))
+
+typedef struct _GstClapperBaseImport GstClapperBaseImport;
+typedef struct _GstClapperBaseImportClass GstClapperBaseImportClass;
+
+#ifdef G_DEFINE_AUTOPTR_CLEANUP_FUNC
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (GstClapperBaseImport, gst_object_unref)
+#endif
+
+struct _GstClapperBaseImport
+{
+  GstBaseTransform parent;
+
+  GMutex lock;
+
+  GstVideoInfo in_info, out_info;
+};
+
+struct _GstClapperBaseImportClass
+{
+  GstBaseTransformClass parent_class;
+
+  GstBufferPool * (* create_upstream_pool) (GstClapperBaseImport *bi,
+                                            GstStructure        **config);
+};
+
+GType gst_clapper_base_import_get_type (void);
+
+gboolean gst_clapper_base_import_map_buffers (GstClapperBaseImport *bi,
+    GstBuffer *in_buf, GstBuffer *out_buf, GstMapFlags in_flags, GstMapFlags out_flags,
+    GstVideoFrame *frame, GstMapInfo *info, GstMemory **mem);
+
+G_END_DECLS

lib/gst/plugin/gstclappergdkbufferpool.c

@@ -0,0 +1,173 @@
+/*
+ * 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 "gstclappergdkbufferpool.h"
+
+#define GST_CAT_DEFAULT gst_clapper_gdk_buffer_pool_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+#define parent_class gst_clapper_gdk_buffer_pool_parent_class
+G_DEFINE_TYPE (GstClapperGdkBufferPool, gst_clapper_gdk_buffer_pool, GST_TYPE_BUFFER_POOL);
+
+static void
+gst_clapper_gdk_buffer_pool_init (GstClapperGdkBufferPool *pool)
+{
+}
+
+static const gchar **
+gst_clapper_gdk_buffer_pool_get_options (GstBufferPool *pool)
+{
+  static const gchar *options[] = {
+    GST_BUFFER_POOL_OPTION_VIDEO_META,
+    NULL
+  };
+
+  return options;
+}
+
+static gboolean
+gst_clapper_gdk_buffer_pool_set_config (GstBufferPool *pool, GstStructure *config)
+{
+  GstClapperGdkBufferPool *self = GST_CLAPPER_GDK_BUFFER_POOL_CAST (pool);
+  GstCaps *caps = NULL;
+  guint size, min_buffers, max_buffers;
+  GstVideoInfo info;
+  GstClapperGdkMemory *clapper_mem;
+
+  if (!gst_buffer_pool_config_get_params (config, &caps, &size,
+      &min_buffers, &max_buffers)) {
+    GST_WARNING_OBJECT (self, "Invalid buffer pool config");
+    return FALSE;
+  }
+
+  if (!caps || !gst_video_info_from_caps (&info, caps)) {
+    GST_WARNING_OBJECT (pool, "Could not parse caps into video info");
+    return FALSE;
+  }
+
+  gst_clear_object (&self->allocator);
+  self->allocator = GST_CLAPPER_GDK_ALLOCATOR_CAST (
+      gst_allocator_find (GST_CLAPPER_GDK_MEMORY_TYPE_NAME));
+
+  if (G_UNLIKELY (!self->allocator)) {
+    GST_ERROR_OBJECT (self, "ClapperGdkAllocator is unavailable");
+    return FALSE;
+  }
+
+  clapper_mem = GST_CLAPPER_GDK_MEMORY_CAST (
+      gst_clapper_gdk_allocator_alloc (self->allocator, &info));
+  if (G_UNLIKELY (!clapper_mem)) {
+    GST_ERROR_OBJECT (self, "Cannot create ClapperGdkMemory");
+    return FALSE;
+  }
+
+  gst_buffer_pool_config_set_params (config, caps,
+      GST_VIDEO_INFO_SIZE (&clapper_mem->info), min_buffers, max_buffers);
+  gst_memory_unref (GST_MEMORY_CAST (clapper_mem));
+
+  self->info = info;
+
+  GST_DEBUG_OBJECT (self, "Set buffer pool config: %" GST_PTR_FORMAT, config);
+
+  return GST_BUFFER_POOL_CLASS (parent_class)->set_config (pool, config);
+}
+
+static GstFlowReturn
+gst_clapper_gdk_buffer_pool_alloc (GstBufferPool *pool, GstBuffer **buffer,
+    GstBufferPoolAcquireParams *params)
+{
+  GstClapperGdkBufferPool *self = GST_CLAPPER_GDK_BUFFER_POOL_CAST (pool);
+  GstMemory *mem;
+  GstClapperGdkMemory *clapper_mem;
+
+  mem = gst_clapper_gdk_allocator_alloc (self->allocator, &self->info);
+  if (G_UNLIKELY (!mem)) {
+    GST_ERROR_OBJECT (self, "Cannot create ClapperGdkMemory");
+    return GST_FLOW_ERROR;
+  }
+
+  clapper_mem = GST_CLAPPER_GDK_MEMORY_CAST (mem);
+
+  *buffer = gst_buffer_new ();
+  gst_buffer_append_memory (*buffer, mem);
+
+  gst_buffer_add_video_meta_full (*buffer, GST_VIDEO_FRAME_FLAG_NONE,
+      GST_VIDEO_INFO_FORMAT (&self->info), GST_VIDEO_INFO_WIDTH (&self->info),
+      GST_VIDEO_INFO_HEIGHT (&self->info), GST_VIDEO_INFO_N_PLANES (&self->info),
+      clapper_mem->info.offset, clapper_mem->info.stride);
+
+  GST_TRACE_OBJECT (self, "Allocated %" GST_PTR_FORMAT, *buffer);
+
+  return GST_FLOW_OK;
+}
+
+static void
+gst_clapper_gdk_buffer_reset_buffer (GstBufferPool *pool, GstBuffer *buffer)
+{
+  GstClapperGdkMemory *clapper_mem;
+
+  GST_TRACE ("Reset %" GST_PTR_FORMAT, buffer);
+
+  clapper_mem = GST_CLAPPER_GDK_MEMORY_CAST (gst_buffer_peek_memory (buffer, 0));
+  g_clear_object (&clapper_mem->texture);
+
+  return GST_BUFFER_POOL_CLASS (parent_class)->reset_buffer (pool, buffer);
+}
+
+static void
+gst_clapper_gdk_buffer_pool_dispose (GObject *object)
+{
+  GstClapperGdkBufferPool *self = GST_CLAPPER_GDK_BUFFER_POOL_CAST (object);
+
+  gst_clear_object (&self->allocator);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, dispose, (object));
+}
+
+static void
+gst_clapper_gdk_buffer_pool_class_init (GstClapperGdkBufferPoolClass *klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+  GstBufferPoolClass *bufferpool_class = (GstBufferPoolClass *) klass;
+
+  gobject_class->dispose = gst_clapper_gdk_buffer_pool_dispose;
+
+  bufferpool_class->get_options = gst_clapper_gdk_buffer_pool_get_options;
+  bufferpool_class->set_config = gst_clapper_gdk_buffer_pool_set_config;
+  bufferpool_class->alloc_buffer = gst_clapper_gdk_buffer_pool_alloc;
+  bufferpool_class->reset_buffer = gst_clapper_gdk_buffer_reset_buffer;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clappergdkbufferpool", 0,
+      "Clapper Gdk Buffer Pool");
+}
+
+GstBufferPool *
+gst_clapper_gdk_buffer_pool_new (void)
+{
+  GstClapperGdkBufferPool *self;
+
+  self = g_object_new (GST_TYPE_CLAPPER_GDK_BUFFER_POOL, NULL);
+  gst_object_ref_sink (self);
+
+  return GST_BUFFER_POOL_CAST (self);
+}

lib/gst/plugin/gstclappergdkbufferpool.h

@@ -0,0 +1,44 @@
+/*
+ * 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/gstbufferpool.h>
+#include <gst/video/video.h>
+
+#include "gstclappergdkmemory.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_GDK_BUFFER_POOL (gst_clapper_gdk_buffer_pool_get_type())
+G_DECLARE_FINAL_TYPE (GstClapperGdkBufferPool, gst_clapper_gdk_buffer_pool, GST, CLAPPER_GDK_BUFFER_POOL, GstBufferPool)
+
+#define GST_CLAPPER_GDK_BUFFER_POOL_CAST(obj)    ((GstClapperGdkBufferPool *)(obj))
+
+struct _GstClapperGdkBufferPool
+{
+  GstBufferPool parent;
+
+  GstClapperGdkAllocator *allocator;
+  GstVideoInfo info;
+};
+
+GstBufferPool * gst_clapper_gdk_buffer_pool_new (void);
+
+G_END_DECLS

lib/gst/plugin/gstclappergdkmemory.c

@@ -0,0 +1,141 @@
+/*
+ * 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 "gstclappergdkmemory.h"
+#include "gstgtkutils.h"
+
+#define GST_CAT_DEFAULT gst_clapper_gdk_allocator_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+static GstAllocator *_gst_clapper_gdk_allocator = NULL;
+
+#define parent_class gst_clapper_gdk_allocator_parent_class
+G_DEFINE_TYPE (GstClapperGdkAllocator, gst_clapper_gdk_allocator, GST_TYPE_ALLOCATOR);
+
+static void
+gst_clapper_gdk_allocator_free (GstAllocator *self, GstMemory *memory)
+{
+  GstClapperGdkMemory *mem = GST_CLAPPER_GDK_MEMORY_CAST (memory);
+
+  GST_TRACE_OBJECT (self, "Freeing ClapperGdkMemory: %" GST_PTR_FORMAT, mem);
+
+  g_clear_object (&mem->texture);
+  g_free (mem);
+}
+
+static gpointer
+gst_clapper_gdk_mem_map_full (GstMemory *memory, GstMapInfo *info, gsize maxsize)
+{
+  GstClapperGdkMemory *mem = GST_CLAPPER_GDK_MEMORY_CAST (memory);
+
+  return &mem->texture;
+}
+
+static void
+gst_clapper_gdk_mem_unmap_full (GstMemory *memory, GstMapInfo *info)
+{
+  /* NOOP */
+}
+
+static GstMemory *
+gst_clapper_gdk_mem_copy (GstMemory *memory, gssize offset, gssize size)
+{
+  return NULL;
+}
+
+static GstMemory *
+gst_clapper_gdk_mem_share (GstMemory *memory, gssize offset, gssize size)
+{
+  return NULL;
+}
+
+static gboolean
+gst_clapper_gdk_mem_is_span (GstMemory *mem1, GstMemory *mem2, gsize *offset)
+{
+  return FALSE;
+}
+
+static void
+gst_clapper_gdk_allocator_init (GstClapperGdkAllocator *self)
+{
+  GstAllocator *alloc = GST_ALLOCATOR_CAST (self);
+
+  alloc->mem_type = GST_CLAPPER_GDK_MEMORY_TYPE_NAME;
+  alloc->mem_map_full = gst_clapper_gdk_mem_map_full;
+  alloc->mem_unmap_full = gst_clapper_gdk_mem_unmap_full;
+  alloc->mem_copy = gst_clapper_gdk_mem_copy;
+  alloc->mem_share = gst_clapper_gdk_mem_share;
+  alloc->mem_is_span = gst_clapper_gdk_mem_is_span;
+
+  GST_OBJECT_FLAG_SET (self, GST_ALLOCATOR_FLAG_CUSTOM_ALLOC);
+}
+
+static void
+gst_clapper_gdk_allocator_class_init (GstClapperGdkAllocatorClass *klass)
+{
+  GstAllocatorClass *allocator_class = (GstAllocatorClass *) klass;
+
+  allocator_class->alloc = NULL;
+  allocator_class->free = GST_DEBUG_FUNCPTR (gst_clapper_gdk_allocator_free);
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clappergdkallocator", 0,
+      "Clapper Gdk Allocator");
+}
+
+void
+gst_clapper_gdk_memory_init_once (void)
+{
+  static gsize _alloc_init = 0;
+
+  if (g_once_init_enter (&_alloc_init)) {
+    _gst_clapper_gdk_allocator = GST_ALLOCATOR_CAST (
+        g_object_new (GST_TYPE_CLAPPER_GDK_ALLOCATOR, NULL));
+    gst_object_ref_sink (_gst_clapper_gdk_allocator);
+
+    gst_allocator_register (GST_CLAPPER_GDK_MEMORY_TYPE_NAME, _gst_clapper_gdk_allocator);
+    g_once_init_leave (&_alloc_init, 1);
+  }
+}
+
+gboolean
+gst_is_clapper_gdk_memory (GstMemory *memory)
+{
+  return (memory != NULL && memory->allocator != NULL
+      && GST_IS_CLAPPER_GDK_ALLOCATOR (memory->allocator));
+}
+
+GstMemory *
+gst_clapper_gdk_allocator_alloc (GstClapperGdkAllocator *self, const GstVideoInfo *info)
+{
+  GstClapperGdkMemory *mem;
+
+  mem = g_new0 (GstClapperGdkMemory, 1);
+  mem->info = *info;
+
+  gst_memory_init (GST_MEMORY_CAST (mem), 0, GST_ALLOCATOR_CAST (self),
+      NULL, GST_VIDEO_INFO_SIZE (info), 0, 0, GST_VIDEO_INFO_SIZE (info));
+
+  GST_TRACE_OBJECT (self, "Allocated new ClapperGdkMemory: %" GST_PTR_FORMAT, mem);
+
+  return GST_MEMORY_CAST (mem);
+}

lib/gst/plugin/gstclappergdkmemory.h

@@ -0,0 +1,67 @@
+/*
+ * 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/gstmemory.h>
+#include <gst/gstallocator.h>
+#include <gst/video/video.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_GDK_ALLOCATOR (gst_clapper_gdk_allocator_get_type())
+G_DECLARE_FINAL_TYPE (GstClapperGdkAllocator, gst_clapper_gdk_allocator, GST, CLAPPER_GDK_ALLOCATOR, GstAllocator)
+
+#define GST_CLAPPER_GDK_ALLOCATOR_CAST(obj)      ((GstClapperGdkAllocator *)(obj))
+#define GST_CLAPPER_GDK_MEMORY_CAST(mem)         ((GstClapperGdkMemory *)(mem))
+
+#define GST_CLAPPER_GDK_MEMORY_TYPE_NAME         "gst.clapper.gdk.memory"
+
+#define GST_CAPS_FEATURE_CLAPPER_GDK_MEMORY      "memory:ClapperGdkMemory"
+
+#define GST_CLAPPER_GDK_MEMORY_FORMATS           \
+    "RGBA64_LE, RGBA64_BE, ABGR, BGRA, "         \
+    "ARGB, RGBA, BGRx, RGBx, BGR, RGB"           \
+
+/* Formats that `GdkGLTexture` supports */
+#define GST_CLAPPER_GDK_GL_TEXTURE_FORMATS       \
+    "RGBA64_LE, RGBA64_BE, RGBA, RGBx, RGB"      \
+
+typedef struct _GstClapperGdkMemory GstClapperGdkMemory;
+struct _GstClapperGdkMemory
+{
+  GstMemory mem;
+
+  GdkTexture *texture;
+  GstVideoInfo info;
+};
+
+struct _GstClapperGdkAllocator
+{
+  GstAllocator parent;
+};
+
+void        gst_clapper_gdk_memory_init_once     (void);
+
+gboolean    gst_is_clapper_gdk_memory            (GstMemory *memory);
+
+GstMemory * gst_clapper_gdk_allocator_alloc      (GstClapperGdkAllocator *allocator, const GstVideoInfo *info);
+
+G_END_DECLS

lib/gst/plugin/gstclapperglbaseimport.c

@@ -0,0 +1,414 @@
+/*
+ * 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 <gtk/gtk.h>
+#include <gst/gl/gstglfuncs.h>
+
+#include "gstclapperglbaseimport.h"
+#include "gstgtkutils.h"
+
+#if GST_CLAPPER_GL_HAVE_WAYLAND
+#include <gdk/wayland/gdkwayland.h>
+#include <gst/gl/wayland/gstgldisplay_wayland.h>
+#endif
+
+#if GST_CLAPPER_GL_HAVE_X11
+#include <gdk/x11/gdkx.h>
+#endif
+
+#if GST_CLAPPER_GL_HAVE_X11_GLX
+#include <gst/gl/x11/gstgldisplay_x11.h>
+#endif
+#if GST_CLAPPER_GL_HAVE_X11_EGL
+#include <gst/gl/egl/gstgldisplay_egl.h>
+#endif
+
+#define GST_CAT_DEFAULT gst_clapper_gl_base_import_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+#define parent_class gst_clapper_gl_base_import_parent_class
+G_DEFINE_TYPE (GstClapperGLBaseImport, gst_clapper_gl_base_import, GST_TYPE_CLAPPER_BASE_IMPORT);
+
+static void
+gst_clapper_gl_base_import_init (GstClapperGLBaseImport *self)
+{
+  g_mutex_init (&self->lock);
+}
+
+static void
+gst_clapper_gl_base_import_finalize (GObject *object)
+{
+  GstClapperGLBaseImport *self = GST_CLAPPER_GL_BASE_IMPORT_CAST (object);
+
+  g_clear_object (&self->gdk_context);
+  gst_clear_object (&self->gst_context);
+  gst_clear_object (&self->wrapped_context);
+  gst_clear_object (&self->gst_display);
+
+  g_mutex_clear (&self->lock);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
+}
+
+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 (GstClapperGLBaseImport *self)
+{
+  GstClapperGLBaseImportClass *gl_bi_class = GST_CLAPPER_GL_BASE_IMPORT_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;
+  }
+
+  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_CLAPPER_GL_BASE_IMPORT_LOCK (self);
+
+  self->gdk_context = gdk_context;
+
+#if GST_CLAPPER_GL_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_HAVE_X11
+  if (GDK_IS_X11_DISPLAY (gdk_display)) {
+    gpointer display_ptr;
+#if GST_CLAPPER_GL_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_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_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_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_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_CLAPPER_GL_BASE_IMPORT_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_CLAPPER_GL_BASE_IMPORT_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_CLAPPER_GL_BASE_IMPORT_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_CLAPPER_GL_BASE_IMPORT_UNLOCK (self);
+
+  return TRUE;
+}
+
+static gboolean
+ensure_gl_context (GstClapperGLBaseImport *self)
+{
+  GstGLDisplay *gst_display = NULL;
+  GstGLContext *gst_context = NULL;
+  GError *error = NULL;
+  gboolean has_gdk_contexts;
+
+  GST_CLAPPER_GL_BASE_IMPORT_LOCK (self);
+  has_gdk_contexts = (self->gdk_context && self->wrapped_context);
+  GST_CLAPPER_GL_BASE_IMPORT_UNLOCK (self);
+
+  if (!has_gdk_contexts) {
+    if (!(! !gst_gtk_invoke_on_main (
+        (GThreadFunc) (GCallback) retrieve_gl_context_on_main, self))) {
+      GST_ERROR_OBJECT (self, "Could not retrieve Gdk GL context");
+
+      return FALSE;
+    }
+  }
+
+  GST_CLAPPER_GL_BASE_IMPORT_LOCK (self);
+
+  gst_display = gst_object_ref (self->gst_display);
+
+  /* GstGLDisplay operations require 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_CLAPPER_GL_BASE_IMPORT_UNLOCK (self);
+
+      return FALSE;
+    }
+  }
+
+  gst_context = gst_object_ref (self->gst_context);
+
+  GST_CLAPPER_GL_BASE_IMPORT_UNLOCK (self);
+
+  /* Calls `set_context` internally, so we cannot be locked here */
+  gst_gl_display_add_context (gst_display, gst_context);
+  gst_gl_element_propagate_display_context (GST_ELEMENT_CAST (self), gst_display);
+
+  GST_OBJECT_UNLOCK (gst_display);
+
+  gst_object_unref (gst_display);
+  gst_object_unref (gst_context);
+
+  return TRUE;
+}
+
+static void
+gst_clapper_gl_base_import_set_context (GstElement *element, GstContext *context)
+{
+  GstClapperGLBaseImport *self = GST_CLAPPER_GL_BASE_IMPORT_CAST (element);
+
+  GST_DEBUG_OBJECT (self, "Set context");
+
+  GST_CLAPPER_GL_BASE_IMPORT_LOCK (self);
+  gst_gl_handle_set_context (element, context, &self->gst_display,
+      &self->wrapped_context);
+  GST_CLAPPER_GL_BASE_IMPORT_UNLOCK (self);
+
+  GST_ELEMENT_CLASS (parent_class)->set_context (element, context);
+}
+
+static GstStateChangeReturn
+gst_clapper_gl_base_import_change_state (GstElement *element, GstStateChange transition)
+{
+  GstClapperGLBaseImport *self = GST_CLAPPER_GL_BASE_IMPORT_CAST (element);
+  GstStateChangeReturn ret;
+
+  ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
+  if (ret == GST_STATE_CHANGE_FAILURE)
+    return ret;
+
+  switch (transition) {
+    case GST_STATE_CHANGE_NULL_TO_READY:
+      if (!ensure_gl_context (self))
+        return GST_STATE_CHANGE_FAILURE;
+      break;
+    default:
+      break;
+  }
+
+  return ret;
+}
+
+static gboolean
+gst_clapper_gl_base_import_query (GstBaseTransform *bt,
+    GstPadDirection direction, GstQuery *query)
+{
+  GstClapperGLBaseImport *self = GST_CLAPPER_GL_BASE_IMPORT_CAST (bt);
+  gboolean res;
+
+  switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_CONTEXT:
+      GST_CLAPPER_GL_BASE_IMPORT_LOCK (self);
+      res = gst_gl_handle_context_query (GST_ELEMENT_CAST (self), query,
+          self->gst_display, self->gst_context, self->wrapped_context);
+      GST_CLAPPER_GL_BASE_IMPORT_UNLOCK (self);
+      break;
+    default:
+      res = GST_BASE_TRANSFORM_CLASS (parent_class)->query (bt, direction, query);
+      break;
+  }
+
+  return res;
+}
+
+static gboolean
+gst_clapper_gl_base_import_gdk_context_realize (GstClapperGLBaseImport *self, GdkGLContext *gdk_context)
+{
+  GError *error = NULL;
+  gboolean success;
+
+  GST_DEBUG_OBJECT (self, "Realizing GdkGLContext with default implementation");
+
+  gdk_gl_context_set_allowed_apis (gdk_context, GDK_GL_API_GLES);
+  if (!(success = gdk_gl_context_realize (gdk_context, &error))) {
+    GST_WARNING_OBJECT (self, "Could not realize Gdk context with GLES: %s", error->message);
+    g_clear_error (&error);
+  }
+  if (!success) {
+    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_import_class_init (GstClapperGLBaseImportClass *klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+  GstElementClass *gstelement_class = (GstElementClass *) klass;
+  GstBaseTransformClass *gstbasetransform_class = (GstBaseTransformClass *) klass;
+  GstClapperGLBaseImportClass *gl_bi_class = (GstClapperGLBaseImportClass *) klass;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperglbaseimport", 0,
+      "Clapper GL Base Import");
+
+  gobject_class->finalize = gst_clapper_gl_base_import_finalize;
+
+  gstelement_class->set_context = gst_clapper_gl_base_import_set_context;
+  gstelement_class->change_state = gst_clapper_gl_base_import_change_state;
+
+  gstbasetransform_class->query = gst_clapper_gl_base_import_query;
+
+  gl_bi_class->gdk_context_realize = gst_clapper_gl_base_import_gdk_context_realize;
+}

lib/gst/plugin/gstclapperglbaseimport.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 <gtk/gtk.h>
+
+#include "gstclapperbaseimport.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_GL_BASE_IMPORT               (gst_clapper_gl_base_import_get_type())
+#define GST_IS_CLAPPER_GL_BASE_IMPORT(obj)            (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_CLAPPER_GL_BASE_IMPORT))
+#define GST_IS_CLAPPER_GL_BASE_IMPORT_CLASS(klass)    (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_CLAPPER_GL_BASE_IMPORT))
+#define GST_CLAPPER_GL_BASE_IMPORT_GET_CLASS(obj)     (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_CLAPPER_GL_BASE_IMPORT, GstClapperGLBaseImportClass))
+#define GST_CLAPPER_GL_BASE_IMPORT(obj)               (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_CLAPPER_GL_BASE_IMPORT, GstClapperGLBaseImport))
+#define GST_CLAPPER_GL_BASE_IMPORT_CLASS(klass)       (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_CLAPPER_GL_BASE_IMPORT, GstClapperGLBaseImportClass))
+#define GST_CLAPPER_GL_BASE_IMPORT_CAST(obj)          ((GstClapperGLBaseImport *)(obj))
+
+#define GST_CLAPPER_GL_BASE_IMPORT_GET_LOCK(obj)      (&GST_CLAPPER_GL_BASE_IMPORT_CAST(obj)->lock)
+#define GST_CLAPPER_GL_BASE_IMPORT_LOCK(obj)          g_mutex_lock (GST_CLAPPER_GL_BASE_IMPORT_GET_LOCK(obj))
+#define GST_CLAPPER_GL_BASE_IMPORT_UNLOCK(obj)        g_mutex_unlock (GST_CLAPPER_GL_BASE_IMPORT_GET_LOCK(obj))
+
+#define GST_CLAPPER_GL_HAVE_WAYLAND                   (GST_GL_HAVE_WINDOW_WAYLAND && defined (GDK_WINDOWING_WAYLAND))
+#define GST_CLAPPER_GL_HAVE_X11                       (GST_GL_HAVE_WINDOW_X11 && defined (GDK_WINDOWING_X11))
+#define GST_CLAPPER_GL_HAVE_X11_GLX                   (GST_CLAPPER_GL_HAVE_X11 && GST_GL_HAVE_PLATFORM_GLX)
+#define GST_CLAPPER_GL_HAVE_X11_EGL                   (GST_CLAPPER_GL_HAVE_X11 && GST_GL_HAVE_PLATFORM_EGL)
+
+typedef struct _GstClapperGLBaseImport GstClapperGLBaseImport;
+typedef struct _GstClapperGLBaseImportClass GstClapperGLBaseImportClass;
+
+#ifdef G_DEFINE_AUTOPTR_CLEANUP_FUNC
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (GstClapperGLBaseImport, gst_object_unref)
+#endif
+
+struct _GstClapperGLBaseImport
+{
+  GstClapperBaseImport parent;
+
+  GMutex lock;
+
+  GdkGLContext *gdk_context;
+  GstGLContext *gst_context;
+  GstGLContext *wrapped_context;
+  GstGLDisplay *gst_display;
+};
+
+struct _GstClapperGLBaseImportClass
+{
+  GstClapperBaseImportClass parent_class;
+
+  gboolean (* gdk_context_realize) (GstClapperGLBaseImport *gl_bi,
+                                    GdkGLContext           *gdk_context);
+};
+
+GType gst_clapper_gl_base_import_get_type (void);
+
+G_END_DECLS

lib/gst/plugin/gstclapperglimport.c

@@ -0,0 +1,178 @@
+/*
+ * 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 "gstclapperglimport.h"
+#include "gstclappergdkmemory.h"
+
+#define GST_CAT_DEFAULT gst_clapper_gl_import_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+static GstStaticPadTemplate gst_clapper_gl_import_sink_template =
+    GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (
+        GST_VIDEO_CAPS_MAKE_WITH_FEATURES (GST_CAPS_FEATURE_MEMORY_GL_MEMORY,
+            "{ " GST_CLAPPER_GDK_GL_TEXTURE_FORMATS " }") ", "
+            "texture-target = (string) { " GST_GL_TEXTURE_TARGET_2D_STR " }"
+        "; "
+        GST_VIDEO_CAPS_MAKE_WITH_FEATURES (GST_CAPS_FEATURE_MEMORY_GL_MEMORY ", "
+            GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION,
+            "{ " GST_CLAPPER_GDK_GL_TEXTURE_FORMATS " }") ", "
+            "texture-target = (string) { " GST_GL_TEXTURE_TARGET_2D_STR " }"));
+
+static GstStaticPadTemplate gst_clapper_gl_import_src_template =
+    GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (
+        GST_VIDEO_CAPS_MAKE_WITH_FEATURES (GST_CAPS_FEATURE_CLAPPER_GDK_MEMORY,
+            "{ " GST_CLAPPER_GDK_GL_TEXTURE_FORMATS " }")
+        "; "
+        GST_VIDEO_CAPS_MAKE_WITH_FEATURES (GST_CAPS_FEATURE_CLAPPER_GDK_MEMORY ", "
+            GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION,
+            "{ " GST_CLAPPER_GDK_GL_TEXTURE_FORMATS " }")));
+
+#define parent_class gst_clapper_gl_import_parent_class
+G_DEFINE_TYPE (GstClapperGLImport, gst_clapper_gl_import, GST_TYPE_CLAPPER_GL_BASE_IMPORT);
+GST_ELEMENT_REGISTER_DEFINE (clapperglimport, "clapperglimport", GST_RANK_NONE,
+    GST_TYPE_CLAPPER_GL_IMPORT);
+
+static GstBufferPool *
+gst_clapper_gl_import_create_upstream_pool (GstClapperBaseImport *bi, GstStructure **config)
+{
+  GstClapperGLBaseImport *gl_bi = GST_CLAPPER_GL_BASE_IMPORT_CAST (bi);
+  GstBufferPool *pool;
+  GstGLContext *context;
+
+  GST_DEBUG_OBJECT (bi, "Creating new pool");
+
+  GST_CLAPPER_GL_BASE_IMPORT_LOCK (gl_bi);
+  context = gst_object_ref (gl_bi->gst_context);
+  GST_CLAPPER_GL_BASE_IMPORT_UNLOCK (gl_bi);
+
+  pool = gst_gl_buffer_pool_new (context);
+  gst_object_unref (context);
+
+  *config = gst_buffer_pool_get_config (pool);
+
+  gst_buffer_pool_config_add_option (*config, GST_BUFFER_POOL_OPTION_GL_SYNC_META);
+
+  return pool;
+}
+
+static void
+video_frame_unmap_and_free (GstVideoFrame *frame)
+{
+  gst_video_frame_unmap (frame);
+  g_slice_free (GstVideoFrame, frame);
+}
+
+static GstFlowReturn
+gst_clapper_gl_import_transform (GstBaseTransform *bt,
+    GstBuffer *in_buf, GstBuffer *out_buf)
+{
+  GstClapperGLBaseImport *gl_bi = GST_CLAPPER_GL_BASE_IMPORT_CAST (bt);
+  GstClapperBaseImport *bi = GST_CLAPPER_BASE_IMPORT_CAST (bt);
+  GstVideoFrame *frame;
+  GstMapInfo info;
+  GstMemory *memory;
+  GstClapperGdkMemory *clapper_memory;
+  GstGLSyncMeta *sync_meta;
+
+  frame = g_slice_new (GstVideoFrame);
+
+  if (!gst_clapper_base_import_map_buffers (bi, in_buf, out_buf,
+      GST_MAP_READ | GST_MAP_GL, GST_MAP_WRITE, frame, &info, &memory)) {
+    g_slice_free (GstVideoFrame, frame);
+
+    return GST_FLOW_ERROR;
+  }
+
+  clapper_memory = GST_CLAPPER_GDK_MEMORY_CAST (memory);
+
+  GST_CLAPPER_GL_BASE_IMPORT_LOCK (gl_bi);
+
+  /* Must have context active here for both sync meta
+   * and Gdk texture format auto-detection to work */
+  gdk_gl_context_make_current (gl_bi->gdk_context);
+  gst_gl_context_activate (gl_bi->wrapped_context, TRUE);
+
+  sync_meta = gst_buffer_get_gl_sync_meta (in_buf);
+
+  /* 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, gl_bi->gst_context);
+    gst_gl_sync_meta_wait (sync_meta, gl_bi->wrapped_context);
+  }
+
+  /* Keep input data alive as long as necessary,
+   * unmap only after texture is destroyed */
+  clapper_memory->texture = gdk_gl_texture_new (
+      gl_bi->gdk_context,
+      *(guint *) GST_VIDEO_FRAME_PLANE_DATA (frame, 0),
+      GST_VIDEO_FRAME_WIDTH (frame),
+      GST_VIDEO_FRAME_HEIGHT (frame),
+      (GDestroyNotify) video_frame_unmap_and_free,
+      frame);
+
+  gst_gl_context_activate (gl_bi->wrapped_context, FALSE);
+  gdk_gl_context_clear_current ();
+
+  GST_CLAPPER_GL_BASE_IMPORT_UNLOCK (gl_bi);
+
+  gst_memory_unmap (memory, &info);
+
+  return GST_FLOW_OK;
+}
+
+static void
+gst_clapper_gl_import_init (GstClapperGLImport *self)
+{
+}
+
+static void
+gst_clapper_gl_import_class_init (GstClapperGLImportClass *klass)
+{
+  GstElementClass *gstelement_class = (GstElementClass *) klass;
+  GstBaseTransformClass *gstbasetransform_class = (GstBaseTransformClass *) klass;
+  GstClapperBaseImportClass *bi_class = (GstClapperBaseImportClass *) klass;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperglimport", 0,
+      "Clapper GL Import");
+
+  gstbasetransform_class->transform = gst_clapper_gl_import_transform;
+
+  bi_class->create_upstream_pool = gst_clapper_gl_import_create_upstream_pool;
+
+  gst_element_class_set_metadata (gstelement_class,
+      "Clapper GL import",
+      "Filter/Video", "Imports GL memory into ClapperGdkMemory",
+      "Rafał Dzięgiel <rafostar.github@gmail.com>");
+
+  gst_element_class_add_static_pad_template (gstelement_class,
+      &gst_clapper_gl_import_sink_template);
+  gst_element_class_add_static_pad_template (gstelement_class,
+      &gst_clapper_gl_import_src_template);
+}

lib/gst/plugin/gstclapperglimport.h

@@ -0,0 +1,38 @@
+/*
+ * 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 "gstclapperglbaseimport.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_GL_IMPORT (gst_clapper_gl_import_get_type())
+G_DECLARE_FINAL_TYPE (GstClapperGLImport, gst_clapper_gl_import, GST, CLAPPER_GL_IMPORT, GstClapperGLBaseImport)
+
+#define GST_CLAPPER_GL_IMPORT_CAST(obj)        ((GstClapperGLImport *)(obj))
+
+struct _GstClapperGLImport
+{
+  GstClapperGLBaseImport parent;
+};
+
+GST_ELEMENT_REGISTER_DECLARE (clapperglimport);
+
+G_END_DECLS

lib/gst/plugin/gstclapperimport.c

@@ -0,0 +1,128 @@
+/*
+ * 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 "gstclapperimport.h"
+#include "gstclappergdkmemory.h"
+#include "gstgtkutils.h"
+
+#define GST_CAT_DEFAULT gst_clapper_import_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+static GstStaticPadTemplate gst_clapper_import_sink_template =
+    GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (
+        GST_VIDEO_CAPS_MAKE ("{ " GST_CLAPPER_GDK_MEMORY_FORMATS " }")));
+
+static GstStaticPadTemplate gst_clapper_import_src_template =
+    GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (
+        GST_VIDEO_CAPS_MAKE_WITH_FEATURES (GST_CAPS_FEATURE_CLAPPER_GDK_MEMORY,
+            "{ " GST_CLAPPER_GDK_MEMORY_FORMATS " }")));
+
+#define parent_class gst_clapper_import_parent_class
+G_DEFINE_TYPE (GstClapperImport, gst_clapper_import, GST_TYPE_CLAPPER_BASE_IMPORT);
+GST_ELEMENT_REGISTER_DEFINE (clapperimport, "clapperimport", GST_RANK_NONE,
+    GST_TYPE_CLAPPER_IMPORT);
+
+static GstBufferPool *
+gst_clapper_import_create_upstream_pool (GstClapperBaseImport *bi, GstStructure **config)
+{
+  GstClapperImport *self = GST_CLAPPER_IMPORT_CAST (bi);
+  GstBufferPool *pool;
+
+  GST_DEBUG_OBJECT (self, "Creating new upstream pool");
+
+  pool = gst_video_buffer_pool_new ();
+  *config = gst_buffer_pool_get_config (pool);
+
+  return pool;
+}
+
+static void
+video_frame_unmap_and_free (GstVideoFrame *frame)
+{
+  gst_video_frame_unmap (frame);
+  g_slice_free (GstVideoFrame, frame);
+}
+
+static GstFlowReturn
+gst_clapper_import_transform (GstBaseTransform *bt,
+    GstBuffer *in_buf, GstBuffer *out_buf)
+{
+  GstClapperBaseImport *bi = GST_CLAPPER_BASE_IMPORT_CAST (bt);
+  GstVideoFrame *frame;
+  GstMapInfo info;
+  GstMemory *memory;
+
+  frame = g_slice_new (GstVideoFrame);
+
+  if (!gst_clapper_base_import_map_buffers (bi, in_buf, out_buf,
+      GST_MAP_READ, GST_MAP_WRITE, frame, &info, &memory)) {
+    g_slice_free (GstVideoFrame, frame);
+
+    return GST_FLOW_ERROR;
+  }
+
+  /* Keep frame data alive as long as necessary,
+   * unmap only after bytes are destroyed */
+  GST_CLAPPER_GDK_MEMORY_CAST (memory)->texture = gst_video_frame_into_gdk_texture (
+      frame, (GDestroyNotify) video_frame_unmap_and_free);
+
+  gst_memory_unmap (memory, &info);
+
+  return GST_FLOW_OK;
+}
+
+static void
+gst_clapper_import_init (GstClapperImport *self)
+{
+}
+
+static void
+gst_clapper_import_class_init (GstClapperImportClass *klass)
+{
+  GstElementClass *gstelement_class = (GstElementClass *) klass;
+  GstBaseTransformClass *gstbasetransform_class = (GstBaseTransformClass *) klass;
+  GstClapperBaseImportClass *bi_class = (GstClapperBaseImportClass *) klass;
+
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperimport", 0,
+      "Clapper Import");
+
+  gstbasetransform_class->transform = gst_clapper_import_transform;
+
+  bi_class->create_upstream_pool = gst_clapper_import_create_upstream_pool;
+
+  gst_element_class_set_metadata (gstelement_class,
+      "Clapper import",
+      "Filter/Video", "Imports RAW video data into ClapperGdkMemory",
+      "Rafał Dzięgiel <rafostar.github@gmail.com>");
+
+  gst_element_class_add_static_pad_template (gstelement_class,
+      &gst_clapper_import_sink_template);
+  gst_element_class_add_static_pad_template (gstelement_class,
+      &gst_clapper_import_src_template);
+}

lib/gst/plugin/gstclapperimport.h

@@ -0,0 +1,38 @@
+/*
+ * 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 "gstclapperbaseimport.h"
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_CLAPPER_IMPORT (gst_clapper_import_get_type())
+G_DECLARE_FINAL_TYPE (GstClapperImport, gst_clapper_import, GST, CLAPPER_IMPORT, GstClapperBaseImport)
+
+#define GST_CLAPPER_IMPORT_CAST(obj)        ((GstClapperImport *)(obj))
+
+struct _GstClapperImport
+{
+  GstClapperBaseImport parent;
+};
+
+GST_ELEMENT_REGISTER_DECLARE (clapperimport);
+
+G_END_DECLS

lib/gst/plugin/gstclapperpaintable.c

@@ -0,0 +1,635 @@
+/*
+ * 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"
+#include "gstclappergdkmemory.h"
+#include "gstgtkutils.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);
+
+typedef struct
+{
+  GdkTexture *texture;
+  GstVideoOverlayRectangle *rectangle;
+
+  gint x, y;
+  guint width, height;
+
+  gboolean used;
+} GstClapperGdkOverlay;
+
+static void
+gst_clapper_gdk_overlay_free (GstClapperGdkOverlay *overlay)
+{
+  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 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;
+
+  g_mutex_init (&self->lock);
+  gst_video_info_init (&self->v_info);
+  g_weak_ref_init (&self->widget, NULL);
+
+  self->overlays = g_ptr_array_new_with_free_func (
+      (GDestroyNotify) gst_clapper_gdk_overlay_free);
+
+  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");
+
+  GST_CLAPPER_PAINTABLE_LOCK (self);
+
+  g_weak_ref_clear (&self->widget);
+
+  gst_clear_buffer (&self->pending_buffer);
+  gst_clear_buffer (&self->buffer);
+
+  g_ptr_array_unref (self->overlays);
+
+  GST_CLAPPER_PAINTABLE_UNLOCK (self);
+
+  g_mutex_clear (&self->lock);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
+}
+
+static gboolean
+calculate_display_par (GstClapperPaintable *self, 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;
+
+  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 void
+comp_frame_unmap_and_free (GstVideoFrame *frame)
+{
+  gst_video_frame_unmap (frame);
+  g_slice_free (GstVideoFrame, frame);
+}
+
+static GstClapperGdkOverlay *
+_get_cached_overlay (GPtrArray *overlays, GstVideoOverlayRectangle *rectangle, guint *index)
+{
+  guint i;
+
+  for (i = 0; i < overlays->len; i++) {
+    GstClapperGdkOverlay *overlay = g_ptr_array_index (overlays, i);
+
+    if (overlay->rectangle != rectangle)
+      continue;
+
+    *index = i;
+    return overlay;
+  }
+
+  return NULL;
+}
+
+static void
+gst_clapper_paintable_prepare_overlays (GstClapperPaintable *self)
+{
+  GstVideoOverlayCompositionMeta *comp_meta;
+  guint num_overlays, i;
+
+  /* As long as this is called from main thread, no need to lock here */
+  if (G_UNLIKELY (!self->buffer)
+      || !(comp_meta = gst_buffer_get_video_overlay_composition_meta (self->buffer))) {
+    guint n_pending = self->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->overlays, 0, n_pending);
+    }
+
+    return;
+  }
+
+  GST_LOG_OBJECT (self, "Preparing overlays...");
+
+  /* Mark all old overlays as unused */
+  for (i = 0; i < self->overlays->len; i++) {
+    GstClapperGdkOverlay *overlay = g_ptr_array_index (self->overlays, i);
+    overlay->used = FALSE;
+  }
+
+  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 *vmeta;
+    GstVideoInfo vinfo;
+    GstVideoOverlayRectangle *rectangle;
+    GstClapperGdkOverlay *overlay;
+    GstVideoOverlayFormatFlags flags, alpha_flags = 0;
+    gint comp_x, comp_y;
+    guint comp_width, comp_height, cached_index;
+
+    rectangle = gst_video_overlay_composition_get_rectangle (comp_meta->overlay, i);
+
+    if ((overlay = _get_cached_overlay (self->overlays, rectangle, &cached_index))) {
+      overlay->used = TRUE;
+
+      /* Place overlay at expected position */
+      if (i != cached_index) {
+        GST_LOG ("Rearranging overlay position: %u => %u", cached_index, i);
+
+        overlay = g_ptr_array_steal_index_fast (self->overlays, cached_index);
+        g_ptr_array_insert (self->overlays, i, overlay);
+      }
+
+      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);
+    comp_frame = g_slice_new (GstVideoFrame);
+
+    /* Update overlay video info from video meta */
+    if ((vmeta = gst_buffer_get_video_meta (comp_buffer))) {
+      gst_video_info_set_format (&vinfo, vmeta->format, vmeta->width, vmeta->height);
+      vinfo.stride[0] = vmeta->stride[0];
+    }
+
+    if (G_UNLIKELY (!gst_video_frame_map (comp_frame, &vinfo, comp_buffer, GST_MAP_READ))) {
+      g_slice_free (GstVideoFrame, comp_frame);
+      return;
+    }
+
+    if ((texture = gst_video_frame_into_gdk_texture (
+        comp_frame, (GDestroyNotify) comp_frame_unmap_and_free))) {
+      overlay = g_slice_new (GstClapperGdkOverlay);
+      overlay->texture = texture;
+      overlay->rectangle = gst_video_overlay_rectangle_ref (rectangle);
+      overlay->x = comp_x;
+      overlay->y = comp_y;
+      overlay->width = comp_width;
+      overlay->height = comp_height;
+      overlay->used = TRUE;
+
+      GST_TRACE ("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->overlays, i, overlay);
+    }
+  }
+
+  /* Remove all overlays that are not going to be used */
+  for (i = self->overlays->len; i > 0; i--) {
+    GstClapperGdkOverlay *overlay = g_ptr_array_index (self->overlays, i - 1);
+
+    if (!overlay->used) {
+      GST_TRACE ("Removing unused cached overlay: %" GST_PTR_FORMAT, overlay);
+      g_ptr_array_remove (self->overlays, overlay);
+    }
+  }
+
+  if (G_UNLIKELY (num_overlays != self->overlays->len)) {
+    GST_WARNING_OBJECT (self, "Some overlays could not be prepared, %u != %u",
+        num_overlays, self->overlays->len);
+  }
+
+  GST_LOG_OBJECT (self, "Prepared overlays: %u", self->overlays->len);
+}
+
+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;
+
+  gst_clear_buffer (&self->buffer);
+  self->buffer = self->pending_buffer;
+  self->pending_buffer = NULL;
+
+  self->draw_id = 0;
+
+  GST_CLAPPER_PAINTABLE_UNLOCK (self);
+
+  gst_clapper_paintable_prepare_overlays (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_buffer (GstClapperPaintable *self, GstBuffer *buffer)
+{
+  GST_CLAPPER_PAINTABLE_LOCK (self);
+
+  if (self->draw_id > 0) {
+    GST_CLAPPER_PAINTABLE_UNLOCK (self);
+    GST_TRACE ("Already have pending buffer, skipping %" GST_PTR_FORMAT, buffer);
+
+    return;
+  }
+
+  gst_buffer_replace (&self->pending_buffer, buffer);
+  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, 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) {
+    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);
+
+  return;
+}
+
+/*
+ * GdkPaintableInterface
+ */
+static void
+gst_clapper_paintable_snapshot_internal (GstClapperPaintable *self,
+    GdkSnapshot *snapshot, gdouble width, gdouble height,
+    gint widget_width, gint widget_height)
+{
+  GstMemory *memory;
+  GstMapInfo info;
+  gfloat scale_x, scale_y;
+  guint i;
+
+  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) {
+      gdouble bar_height = (widget_height - height) / 2;
+
+      gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, 0, width, -bar_height));
+      gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, height, width, bar_height + 0.5));
+    } else if (widget_width - width > 0) {
+      gdouble bar_width = (widget_width - width) / 2;
+
+      gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, 0, -bar_width, height));
+      gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (width, 0, bar_width + 0.5, height));
+    }
+  }
+
+  /* Buffer is accessed only from main thread, so no locking required */
+  if (!self->buffer) {
+    gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, 0, width, height));
+    return;
+  }
+
+  GST_TRACE ("Snapshot %" GST_PTR_FORMAT, self->buffer);
+
+  memory = gst_buffer_peek_memory (self->buffer, 0);
+
+  /* If we cannot map, just draw black */
+  if (G_UNLIKELY (!gst_memory_map (memory, &info, GST_MAP_READ))) {
+    gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, 0, width, height));
+    GST_WARNING_OBJECT (self, "Could not map %" GST_PTR_FORMAT, self->buffer);
+
+    return;
+  }
+
+  gtk_snapshot_append_texture (snapshot,
+      GST_CLAPPER_GDK_MEMORY_CAST (memory)->texture,
+      &GRAPHENE_RECT_INIT (0, 0, width, height));
+  gst_memory_unmap (memory, &info);
+
+  /* FIXME: Draw black BG here when import format has-alpha */
+  //gtk_snapshot_append_color (snapshot, &self->bg, &GRAPHENE_RECT_INIT (0, 0, width, height));
+
+  /* Finally append prepared overlays */
+  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));
+  }
+}
+
+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))) {
+    widget_width = gtk_widget_get_width (widget);
+    widget_height = gtk_widget_get_height (widget);
+
+    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);
+
+  if (self->buffer) {
+    GtkSnapshot *snapshot;
+    GdkPaintable *ret;
+
+    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);
+
+    if ((ret = gtk_snapshot_free_to_paintable (snapshot, NULL)))
+      return ret;
+  }
+
+  return gdk_paintable_new_empty (0, 0);
+}
+
+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 +1,74 @@
+/*
+ * 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_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;
+
+  GstBuffer *pending_buffer, *buffer;
+  GPtrArray *overlays;
+  GstVideoInfo v_info;
+
+  GdkRGBA bg;
+
+  GWeakRef widget;
+
+  /* Sink properties */
+  gint par_n, par_d;
+
+  /* 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_set_widget             (GstClapperPaintable *paintable, GtkWidget *widget);
+void                  gst_clapper_paintable_set_buffer             (GstClapperPaintable *paintable, GstBuffer *buffer);
+gboolean              gst_clapper_paintable_set_video_info         (GstClapperPaintable *paintable, 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 +1,838 @@
+/*
+ * 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 "gstclappergdkmemory.h"
+#include "gstclappergdkbufferpool.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 GstStaticPadTemplate gst_clapper_sink_template =
+    GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (
+        GST_VIDEO_CAPS_MAKE_WITH_FEATURES (GST_CAPS_FEATURE_CLAPPER_GDK_MEMORY,
+            "{ " GST_CLAPPER_GDK_MEMORY_FORMATS " }")
+        "; "
+        GST_VIDEO_CAPS_MAKE_WITH_FEATURES (GST_CAPS_FEATURE_CLAPPER_GDK_MEMORY ", "
+            GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION,
+            "{ " GST_CLAPPER_GDK_MEMORY_FORMATS " }")));
+
+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;
+}
+
+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;
+
+  if ((x == self->last_pos_x && y == self->last_pos_y)
+      || GST_STATE (self) < GST_STATE_PLAYING)
+    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;
+  gdouble stream_x, stream_y;
+  GdkEventType event_type;
+  const gchar *event_name;
+
+  if (GST_STATE (self) < GST_STATE_PLAYING)
+    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 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;
+  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);
+
+  if (need_pool) {
+    GstStructure *config;
+
+    GST_DEBUG_OBJECT (self, "Creating new pool");
+
+    pool = gst_clapper_gdk_buffer_pool_new ();
+    config = gst_buffer_pool_get_config (pool);
+
+    gst_buffer_pool_config_add_option (config, GST_BUFFER_POOL_OPTION_VIDEO_META);
+    gst_buffer_pool_config_set_params (config, caps, size, 2, 0);
+
+    if (!gst_buffer_pool_set_config (pool, config)) {
+      gst_object_unref (pool);
+
+      GST_DEBUG_OBJECT (self, "Failed to set config");
+      return FALSE;
+    }
+  }
+
+  gst_query_add_allocation_pool (query, pool, size, 2, 0);
+  if (pool)
+    gst_object_unref (pool);
+
+  gst_query_add_allocation_meta (query,
+      GST_VIDEO_OVERLAY_COMPOSITION_META_API_TYPE, NULL);
+
+  /* We also support various metadata */
+  gst_query_add_allocation_meta (query, GST_VIDEO_META_API_TYPE, NULL);
+
+  return TRUE;
+}
+
+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 ());
+
+    gtk_window_set_default_size (self->window, 640, 480);
+    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)
+        gst_clapper_paintable_set_buffer (self->paintable, NULL);
+      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);
+  gboolean res;
+
+  GST_INFO_OBJECT (self, "Set caps: %" GST_PTR_FORMAT, caps);
+  GST_CLAPPER_SINK_LOCK (self);
+
+  if (!gst_video_info_from_caps (&self->v_info, caps)) {
+    GST_CLAPPER_SINK_UNLOCK (self);
+    return FALSE;
+  }
+
+  if (G_UNLIKELY (!self->widget)) {
+    GST_CLAPPER_SINK_UNLOCK (self);
+    GST_ELEMENT_ERROR (self, RESOURCE, NOT_FOUND,
+        ("Output widget was destroyed"), (NULL));
+
+    return FALSE;
+  }
+
+  res = gst_clapper_paintable_set_video_info (self->paintable, &self->v_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_paintable_set_buffer (self->paintable, buffer);
+  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_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");
+
+  g_mutex_clear (&self->lock);
+
+  GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
+}
+
+static void
+gst_clapper_sink_class_init (GstClapperSinkClass *klass)
+{
+  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->start = gst_clapper_sink_start;
+  gstbasesink_class->stop = gst_clapper_sink_stop;
+
+  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>");
+
+  gst_element_class_add_static_pad_template (gstelement_class,
+      &gst_clapper_sink_template);
+}
+
+/*
+ * 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 +1,70 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include <gtk/gtk.h>
+#include <gst/gst.h>
+#include <gst/video/gstvideosink.h>
+#include <gst/video/video.h>
+
+#include "gstclapperpaintable.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;
+  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/gstgtkutils.c

@@ -0,0 +1,131 @@
+/*
+ * 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, GDestroyNotify free_func)
+{
+  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),
+      free_func, frame);
+
+  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 +1,33 @@
+/*
+ * 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>
+
+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, GDestroyNotify free_func);

lib/gst/plugin/gstplugin.c

@@ -0,0 +1,46 @@
+/*
+ * 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 "gstclapperimport.h"
+#include "gstclapperglimport.h"
+#include "gstclappersink.h"
+#include "gstclappergdkmemory.h"
+
+static gboolean
+plugin_init (GstPlugin *plugin)
+{
+  gboolean res = FALSE;
+
+  res |= GST_ELEMENT_REGISTER (clapperimport, plugin);
+  res |= GST_ELEMENT_REGISTER (clapperglimport, plugin);
+  res |= GST_ELEMENT_REGISTER (clappersink, plugin);
+
+  if (res)
+    gst_clapper_gdk_memory_init_once ();
+
+  return res;
+}
+
+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/meson.build

@@ -0,0 +1,69 @@
+gst_plugins_libdir = join_paths(prefix, libdir, 'gstreamer-1.0')
+
+gst_clapper_plugin_args = [
+  '-DHAVE_CONFIG_H',
+  '-DGST_USE_UNSTABLE_API',
+]
+gst_clapper_plugin_deps = [
+  gtk4_dep,
+  gst_dep,
+  gstbase_dep,
+  gstvideo_dep,
+  gstallocators_dep,
+]
+
+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
+
+if not have_gtk_gl_windowing
+  if gst_clapper_plugin_option.enabled()
+    error('GTK4 widget requires GL windowing')
+  else
+    subdir_done()
+  endif
+endif
+
+if not gtk4_dep.version().version_compare('>=4.6.0')
+  if gst_clapper_plugin_option.enabled()
+    error('GTK4 version on this system is too old, plugin needs 4.6.0+')
+  else
+    subdir_done()
+  endif
+endif
+
+gst_clapper_plugin_sources = [
+  'gstclappergdkmemory.c',
+  'gstclappergdkbufferpool.c',
+  'gstclapperbaseimport.c',
+  'gstclapperglbaseimport.c',
+  'gstclapperimport.c',
+  'gstclapperglimport.c',
+  'gstclappersink.c',
+  'gstclapperpaintable.c',
+  'gstgtkutils.c',
+  'gstplugin.c',
+]
+
+library('gstclapper',
+  gst_clapper_plugin_sources,
+  c_args: gst_clapper_plugin_args,
+  include_directories: configinc,
+  dependencies: gst_clapper_plugin_deps + gtk_deps,
+  install: true,
+  install_dir: gst_plugins_libdir,
+)

lib/meson.build

@@ -1,5 +1,5 @@
 glib_req = '>= 2.56.0'
-gst_req = '>= 1.18.0'
+gst_req = '>= 1.20.0'
 
 api_version = '1.0'
 libversion = meson.project_version()
@@ -132,7 +132,7 @@ 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 +184,7 @@ 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
@@ -200,6 +200,8 @@ gsttag_dep = dependency('gstreamer-tag-1.0', version: gst_req,
   fallback: ['gst-plugins-base', 'tag_dep'])
 gstvideo_dep = dependency('gstreamer-video-1.0', version: gst_req,
   fallback: ['gst-plugins-base', 'video_dep'])
+gstallocators_dep = dependency('gstreamer-allocators-1.0', version: gst_req,
+  fallback : ['gst-plugins-base', 'allocators_dep'])
 
 # GStreamer OpenGL
 gstgl_dep = dependency('gstreamer-gl-1.0', version: gst_req,
@@ -251,21 +253,49 @@ 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)
-if not gir.found()
-  error('Clapper requires GI bindings to be compiled')
-endif
-
+gir = find_program('g-ir-scanner')
 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'
 ]
+
+gtk_deps = [gstgl_dep, gstglproto_dep]
+have_gtk_gl_windowing = false
+
+gtk4_dep = dependency('gtk4', required: true)
+
+if not gtk4_dep.version().version_compare('>=4.0.0')
+  error('GTK4 version on this system is too old')
+endif
+
+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()
+    gtk_deps += gtk_x11_dep
+    if gst_gl_have_platform_glx
+      gtk_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()
+    gtk_deps += [gtk_wayland_dep, gstglwayland_dep]
+    have_gtk_gl_windowing = true
+  endif
+endif
+
+if gst_gl_have_platform_egl
+  gtk_deps += gstglegl_dep
+endif
+
 subdir('gst')
 configure_file(output: 'config.h', configuration: cdata)

meson.build

@@ -19,7 +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')
+if get_option('lib') or not get_option('gst-plugin').disabled()
   subdir('lib')
 endif
 

meson_options.txt

@@ -8,6 +8,11 @@ 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('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 +16,31 @@ class ClapperPlayer extends GstClapper.Clapper
 {
     _init()
     {
-        const gtk4plugin = new GstClapper.ClapperGtk4Plugin();
-        const glsinkbin = Gst.ElementFactory.make('glsinkbin', null);
-        glsinkbin.sink = gtk4plugin.video_sink;
+        let vsink = null;
+        const use_legacy_sink = GLib.getenv('CLAPPER_USE_LEGACY_SINK');
+
+        if(!use_legacy_sink || use_legacy_sink != '1') {
+            vsink = Gst.parse_bin_from_description('glupload ! glcolorconvert'
+                + ' ! clapperglimport ! clappersink name=clappersink', true);
+
+            if(vsink)
+                this.clappersink = vsink.get_by_name('clappersink');
+        }
+
+        if(!vsink) {
+            vsink = Gst.ElementFactory.make('glsinkbin', null);
+            const gtk4plugin = new GstClapper.ClapperGtk4Plugin();
+
+            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 +53,7 @@ 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 +632,7 @@ 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)) {