Merge pull request #438 from Rafostar/download-cache

clapper: Add media caching via download to local storage

examples/clapper-gtk/download_cache/python/example.py

@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+
+import gi
+gi.require_version('Adw', '1')
+gi.require_version('Clapper', '0.0')
+gi.require_version('ClapperGtk', '0.0')
+gi.require_version('GLib', '2.0')
+gi.require_version('Gtk', '4.0')
+from gi.repository import Adw, Clapper, ClapperGtk, GLib, Gtk
+import shutil
+
+Clapper.init(None)
+
+download_dir = GLib.build_filenamev([GLib.get_user_cache_dir(), "example_download_dir", None])
+print('Using ceche directory: {0}'.format(download_dir))
+
+def on_download_complete(player, item, location):
+    # Media downloaded. Data from this file is still used for current playback (including seeking).
+    print('Download complete: {0} => {1}'.format(item.props.uri, location))
+
+def on_activate(app):
+    win = Gtk.ApplicationWindow(application=app, default_width=640, default_height=396)
+    video = ClapperGtk.Video()
+    controls = ClapperGtk.SimpleControls(fullscreenable=False)
+
+    # Enable local storage caching and monitor it
+    video.props.player.set_download_dir(download_dir)
+    video.props.player.set_download_enabled(True)
+    video.props.player.connect('download-complete', on_download_complete)
+
+    # Configure playback
+    video.props.player.props.queue.set_progression_mode(Clapper.QueueProgressionMode.CAROUSEL)
+    video.props.player.set_autoplay(True)
+
+    # Create and add media for playback
+    item_1 = Clapper.MediaItem(uri='http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4')
+    item_2 = Clapper.MediaItem(uri='http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ElephantsDream.mp4')
+    video.props.player.props.queue.add_item(item_1)
+    video.props.player.props.queue.add_item(item_2)
+
+    # Assemble window
+    video.add_fading_overlay(controls)
+    win.set_child(video)
+    win.present()
+
+# Create a new application
+app = Adw.Application(application_id='com.example.ClapperDownloadCache')
+app.connect('activate', on_activate)
+
+# Run the application
+app.run(None)
+
+# Finally app should cleanup before exit. Possibly moving data to
+# another dir if it wants to use it on next run and deleting what's
+# left (so any unfinished downloads will also be removed).
+print('Cleanup')
+shutil.rmtree(download_dir)

src/lib/clapper/clapper-app-bus-private.h

@@ -47,6 +47,8 @@ void clapper_app_bus_post_refresh_timeline (ClapperAppBus *app_bus, GstObject *s
 
 void clapper_app_bus_post_simple_signal (ClapperAppBus *app_bus, GstObject *src, guint signal_id);
 
+void clapper_app_bus_post_object_desc_signal (ClapperAppBus *app_bus, GstObject *src, guint signal_id, GstObject *object, const gchar *desc);
+
 void clapper_app_bus_post_desc_with_details_signal (ClapperAppBus *app_bus, GstObject *src, guint signal_id, const gchar *desc, const gchar *details);
 
 void clapper_app_bus_post_error_signal (ClapperAppBus *app_bus, GstObject *src, guint signal_id, GError *error, const gchar *debug_info);

src/lib/clapper/clapper-app-bus.c

@@ -43,6 +43,7 @@ enum
   CLAPPER_APP_BUS_STRUCTURE_REFRESH_STREAMS,
   CLAPPER_APP_BUS_STRUCTURE_REFRESH_TIMELINE,
   CLAPPER_APP_BUS_STRUCTURE_SIMPLE_SIGNAL,
+  CLAPPER_APP_BUS_STRUCTURE_OBJECT_DESC_SIGNAL,
   CLAPPER_APP_BUS_STRUCTURE_DESC_WITH_DETAILS_SIGNAL,
   CLAPPER_APP_BUS_STRUCTURE_ERROR_SIGNAL
 };
@@ -53,6 +54,7 @@ static ClapperBusQuark _structure_quarks[] = {
   {"refresh-streams", 0},
   {"refresh-timeline", 0},
   {"simple-signal", 0},
+  {"object-desc-signal", 0},
   {"desc-with-details-signal", 0},
   {"error-signal", 0},
   {NULL, 0}
@@ -63,6 +65,7 @@ enum
   CLAPPER_APP_BUS_FIELD_UNKNOWN = 0,
   CLAPPER_APP_BUS_FIELD_PSPEC,
   CLAPPER_APP_BUS_FIELD_SIGNAL_ID,
+  CLAPPER_APP_BUS_FIELD_OBJECT,
   CLAPPER_APP_BUS_FIELD_DESC,
   CLAPPER_APP_BUS_FIELD_DETAILS,
   CLAPPER_APP_BUS_FIELD_ERROR,
@@ -73,6 +76,7 @@ static ClapperBusQuark _field_quarks[] = {
   {"unknown", 0},
   {"pspec", 0},
   {"signal-id", 0},
+  {"object", 0},
   {"desc", 0},
   {"details", 0},
   {"error", 0},
@@ -177,6 +181,37 @@ _handle_simple_signal_msg (GstMessage *msg, const GstStructure *structure)
   g_signal_emit (_MESSAGE_SRC_GOBJECT (msg), signal_id, 0);
 }
 
+void
+clapper_app_bus_post_object_desc_signal (ClapperAppBus *self,
+    GstObject *src, guint signal_id,
+    GstObject *object, const gchar *desc)
+{
+  GstStructure *structure = gst_structure_new_id (_STRUCTURE_QUARK (OBJECT_DESC_SIGNAL),
+      _FIELD_QUARK (SIGNAL_ID), G_TYPE_UINT, signal_id,
+      _FIELD_QUARK (OBJECT), GST_TYPE_OBJECT, object,
+      _FIELD_QUARK (DESC), G_TYPE_STRING, desc,
+      NULL);
+  gst_bus_post (GST_BUS_CAST (self), gst_message_new_application (src, structure));
+}
+
+static inline void
+_handle_object_desc_signal_msg (GstMessage *msg, const GstStructure *structure)
+{
+  guint signal_id = 0;
+  GstObject *object = NULL;
+  gchar *desc = NULL;
+
+  gst_structure_id_get (structure,
+      _FIELD_QUARK (SIGNAL_ID), G_TYPE_UINT, &signal_id,
+      _FIELD_QUARK (OBJECT), GST_TYPE_OBJECT, &object,
+      _FIELD_QUARK (DESC), G_TYPE_STRING, &desc,
+      NULL);
+  g_signal_emit (_MESSAGE_SRC_GOBJECT (msg), signal_id, 0, object, desc);
+
+  gst_object_unref (object);
+  g_free (desc);
+}
+
 void
 clapper_app_bus_post_desc_with_details_signal (ClapperAppBus *self,
     GstObject *src, guint signal_id,
@@ -253,6 +288,8 @@ clapper_app_bus_message_func (GstBus *bus, GstMessage *msg, gpointer user_data G
       _handle_refresh_timeline_msg (msg, structure);
     else if (quark == _STRUCTURE_QUARK (SIMPLE_SIGNAL))
       _handle_simple_signal_msg (msg, structure);
+    else if (quark == _STRUCTURE_QUARK (OBJECT_DESC_SIGNAL))
+      _handle_object_desc_signal_msg (msg, structure);
     else if (quark == _STRUCTURE_QUARK (ERROR_SIGNAL))
       _handle_error_signal_msg (msg, structure);
     else if (quark == _STRUCTURE_QUARK (DESC_WITH_DETAILS_SIGNAL))

src/lib/clapper/clapper-media-item-private.h

@@ -37,6 +37,12 @@ void clapper_media_item_update_from_discoverer_info (ClapperMediaItem *self, Gst
 G_GNUC_INTERNAL
 gboolean clapper_media_item_set_duration (ClapperMediaItem *item, gdouble duration, ClapperAppBus *app_bus);
 
+G_GNUC_INTERNAL
+void clapper_media_item_set_cache_location (ClapperMediaItem *item, const gchar *location);
+
+G_GNUC_INTERNAL
+const gchar * clapper_media_item_get_playback_uri (ClapperMediaItem *item);
+
 G_GNUC_INTERNAL
 void clapper_media_item_set_used (ClapperMediaItem *item, gboolean used);
 

src/lib/clapper/clapper-media-item.c

@@ -50,6 +50,8 @@ struct _ClapperMediaItem
   gchar *container_format;
   gdouble duration;
 
+  gchar *cache_uri;
+
   /* For shuffle */
   gboolean used;
 };
@@ -450,6 +452,41 @@ clapper_media_item_update_from_discoverer_info (ClapperMediaItem *self, GstDisco
   gst_object_unref (player);
 }
 
+/* XXX: Must be set from player thread */
+inline void
+clapper_media_item_set_cache_location (ClapperMediaItem *self, const gchar *location)
+{
+  g_free (self->cache_uri);
+  self->cache_uri = g_filename_to_uri (location, NULL, NULL);
+  GST_DEBUG_OBJECT (self, "Set cache URI: \"%s\"", self->cache_uri);
+}
+
+/* XXX: Can only be read from player thread.
+ * Returns cache URI if available, item URI otherwise. */
+inline const gchar *
+clapper_media_item_get_playback_uri (ClapperMediaItem *self)
+{
+  if (self->cache_uri) {
+    GFile *file = g_file_new_for_uri (self->cache_uri);
+    gboolean exists;
+
+    /* It is an app error if it removes files in non-stopped state,
+     * and this function is only called when starting playback */
+    exists = g_file_query_exists (file, NULL);
+    g_object_unref (file);
+
+    if (exists)
+      return self->cache_uri;
+
+    /* Do not test file existence next time */
+    GST_DEBUG_OBJECT (self, "Cleared cache URI for non-existing file: \"%s\"",
+        self->cache_uri);
+    g_clear_pointer (&self->cache_uri, g_free);
+  }
+
+  return self->uri;
+}
+
 void
 clapper_media_item_set_used (ClapperMediaItem *self, gboolean used)
 {
@@ -505,6 +542,8 @@ clapper_media_item_finalize (GObject *object)
   gst_object_unparent (GST_OBJECT_CAST (self->timeline));
   gst_object_unref (self->timeline);
 
+  g_free (self->cache_uri);
+
   G_OBJECT_CLASS (parent_class)->finalize (object);
 }
 

src/lib/clapper/clapper-playbin-bus.c

@@ -827,6 +827,24 @@ _handle_element_msg (GstMessage *msg, ClapperPlayer *player)
 
     g_free (name);
     g_free (details);
+  } else if (gst_message_has_name (msg, "GstCacheDownloadComplete")) {
+    const GstStructure *structure;
+    const gchar *location;
+    guint signal_id;
+
+    if (G_UNLIKELY (player->played_item == NULL))
+      return;
+
+    structure = gst_message_get_structure (msg);
+    location = gst_structure_get_string (structure, "location");
+    signal_id = g_signal_lookup ("download-complete", CLAPPER_TYPE_PLAYER);
+
+    GST_INFO_OBJECT (player, "Download complete: %s", location);
+    clapper_media_item_set_cache_location (player->played_item, location);
+
+    clapper_app_bus_post_object_desc_signal (player->app_bus,
+        GST_OBJECT_CAST (player), signal_id,
+        GST_OBJECT_CAST (player->played_item), location);
   }
 }
 

src/lib/clapper/clapper-player-private.h

@@ -95,6 +95,8 @@ struct _ClapperPlayer
   gboolean video_enabled;
   gboolean audio_enabled;
   gboolean subtitles_enabled;
+  gchar *download_dir;
+  gboolean download_enabled;
   gdouble audio_offset;
   gdouble subtitle_offset;
 };

src/lib/clapper/clapper-player.c

@@ -43,7 +43,7 @@
 #include "clapper-playbin-bus-private.h"
 #include "clapper-app-bus-private.h"
 #include "clapper-queue-private.h"
-#include "clapper-media-item.h"
+#include "clapper-media-item-private.h"
 #include "clapper-stream-list-private.h"
 #include "clapper-stream-private.h"
 #include "clapper-video-stream-private.h"
@@ -61,6 +61,7 @@
 #define DEFAULT_VIDEO_ENABLED TRUE
 #define DEFAULT_AUDIO_ENABLED TRUE
 #define DEFAULT_SUBTITLES_ENABLED TRUE
+#define DEFAULT_DOWNLOAD_ENABLED FALSE
 
 #define GST_CAT_DEFAULT clapper_player_debug
 GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
@@ -90,6 +91,8 @@ enum
   PROP_VIDEO_ENABLED,
   PROP_AUDIO_ENABLED,
   PROP_SUBTITLES_ENABLED,
+  PROP_DOWNLOAD_DIR,
+  PROP_DOWNLOAD_ENABLED,
   PROP_AUDIO_OFFSET,
   PROP_SUBTITLE_OFFSET,
   PROP_SUBTITLE_FONT_DESC,
@@ -99,6 +102,7 @@ enum
 enum
 {
   SIGNAL_SEEK_DONE,
+  SIGNAL_DOWNLOAD_COMPLETE,
   SIGNAL_MISSING_PLUGIN,
   SIGNAL_WARNING,
   SIGNAL_ERROR,
@@ -278,14 +282,15 @@ void
 clapper_player_handle_playbin_flags_changed (ClapperPlayer *self, const GValue *value)
 {
   gint flags;
-  gboolean video_enabled, audio_enabled, subtitles_enabled;
-  gboolean video_changed, audio_changed, subtitles_changed;
+  gboolean video_enabled, audio_enabled, subtitles_enabled, download_enabled;
+  gboolean video_changed, audio_changed, subtitles_changed, download_changed;
 
   flags = g_value_get_flags (value);
 
   video_enabled = ((flags & CLAPPER_PLAYER_PLAY_FLAG_VIDEO) == CLAPPER_PLAYER_PLAY_FLAG_VIDEO);
   audio_enabled = ((flags & CLAPPER_PLAYER_PLAY_FLAG_AUDIO) == CLAPPER_PLAYER_PLAY_FLAG_AUDIO);
   subtitles_enabled = ((flags & CLAPPER_PLAYER_PLAY_FLAG_TEXT) == CLAPPER_PLAYER_PLAY_FLAG_TEXT);
+  download_enabled = ((flags & CLAPPER_PLAYER_PLAY_FLAG_DOWNLOAD) == CLAPPER_PLAYER_PLAY_FLAG_DOWNLOAD);
 
   GST_OBJECT_LOCK (self);
 
@@ -295,6 +300,8 @@ clapper_player_handle_playbin_flags_changed (ClapperPlayer *self, const GValue *
     self->audio_enabled = audio_enabled;
   if ((subtitles_changed = self->subtitles_enabled != subtitles_enabled))
     self->subtitles_enabled = subtitles_enabled;
+  if ((download_changed = self->download_enabled != download_enabled))
+    self->download_enabled = download_enabled;
 
   GST_OBJECT_UNLOCK (self);
 
@@ -313,6 +320,11 @@ clapper_player_handle_playbin_flags_changed (ClapperPlayer *self, const GValue *
     clapper_app_bus_post_prop_notify (self->app_bus,
         GST_OBJECT_CAST (self), param_specs[PROP_SUBTITLES_ENABLED]);
   }
+  if (download_changed) {
+    GST_INFO_OBJECT (self, "Download enabled: %s", (download_enabled) ? "yes" : "no");
+    clapper_app_bus_post_prop_notify (self->app_bus,
+        GST_OBJECT_CAST (self), param_specs[PROP_DOWNLOAD_ENABLED]);
+  }
 }
 
 void
@@ -438,7 +450,7 @@ clapper_player_set_pending_item (ClapperPlayer *self, ClapperMediaItem *pending_
 
   /* Might be NULL (e.g. after queue is cleared) */
   if (pending_item) {
-    uri = clapper_media_item_get_uri (pending_item);
+    uri = clapper_media_item_get_playback_uri (pending_item);
     suburi = clapper_media_item_get_suburi (pending_item);
   }
 
@@ -725,6 +737,50 @@ clapper_player_reset (ClapperPlayer *self, gboolean pending_dispose)
   }
 }
 
+static inline gchar *
+_make_download_template (ClapperPlayer *self)
+{
+  gchar *download_template = NULL;
+
+  GST_OBJECT_LOCK (self);
+
+  if (self->download_enabled && self->download_dir) {
+    if (g_mkdir_with_parents (self->download_dir, 0755) == 0) {
+      download_template = g_build_filename (self->download_dir, "XXXXXX", NULL);
+    } else {
+      GST_ERROR_OBJECT (self, "Could not create download dir: \"%s\"", self->download_dir);
+    }
+  }
+
+  GST_OBJECT_UNLOCK (self);
+
+  return download_template;
+}
+
+static void
+_element_setup_cb (GstElement *playbin, GstElement *element, ClapperPlayer *self)
+{
+  GstElementFactory *factory = gst_element_get_factory (element);
+
+  if (G_UNLIKELY (factory == NULL))
+    return;
+
+  GST_INFO_OBJECT (self, "Element setup: %s", GST_OBJECT_NAME (factory));
+
+  if (strcmp (GST_OBJECT_NAME (factory), "downloadbuffer") == 0) {
+    gchar *download_template;
+
+    /* Only set props if we have download template */
+    if ((download_template = _make_download_template (self))) {
+      g_object_set (element,
+          "temp-template", download_template,
+          "temp-remove", FALSE,
+          NULL);
+      g_free (download_template);
+    }
+  }
+}
+
 static void
 _about_to_finish_cb (GstElement *playbin, ClapperPlayer *self)
 {
@@ -1505,6 +1561,106 @@ clapper_player_get_subtitles_enabled (ClapperPlayer *self)
   return enabled;
 }
 
+/**
+ * clapper_player_set_download_dir:
+ * @player: a #ClapperPlayer
+ * @path: (type filename): the path of a directory to use for media downloads
+ *
+ * Set a directory that @player will use to store downloads.
+ *
+ * See [property@Clapper.Player:download-enabled] description for more
+ * info how this works.
+ *
+ * Since: 0.8
+ */
+void
+clapper_player_set_download_dir (ClapperPlayer *self, const gchar *path)
+{
+  gboolean changed;
+
+  g_return_if_fail (CLAPPER_IS_PLAYER (self));
+  g_return_if_fail (path != NULL);
+
+  GST_OBJECT_LOCK (self);
+  changed = g_set_str (&self->download_dir, path);
+  GST_OBJECT_UNLOCK (self);
+
+  if (changed) {
+    GST_INFO_OBJECT (self, "Current download dir: %s", path);
+    clapper_app_bus_post_prop_notify (self->app_bus,
+        GST_OBJECT_CAST (self), param_specs[PROP_DOWNLOAD_DIR]);
+  }
+}
+
+/**
+ * clapper_player_get_download_dir:
+ * @player: a #ClapperPlayer
+ *
+ * Get path to a directory set for media downloads.
+ *
+ * Returns: (type filename) (transfer full) (nullable): the path of a directory
+ *   set for media downloads or %NULL if no directory was set yet.
+ *
+ * Since: 0.8
+ */
+gchar *
+clapper_player_get_download_dir (ClapperPlayer *self)
+{
+  gchar *download_dir;
+
+  g_return_val_if_fail (CLAPPER_IS_PLAYER (self), NULL);
+
+  GST_OBJECT_LOCK (self);
+  download_dir = g_strdup (self->download_dir);
+  GST_OBJECT_UNLOCK (self);
+
+  return download_dir;
+}
+
+/**
+ * clapper_player_set_download_enabled:
+ * @player: a #ClapperPlayer
+ * @enabled: whether enabled
+ *
+ * Set whether player should attempt progressive download buffering.
+ *
+ * For this to actually work a [property@Clapper.Player:download-dir]
+ * must also be set.
+ *
+ * Since: 0.8
+ */
+void
+clapper_player_set_download_enabled (ClapperPlayer *self, gboolean enabled)
+{
+  g_return_if_fail (CLAPPER_IS_PLAYER (self));
+
+  clapper_playbin_bus_post_set_play_flag (self->bus, CLAPPER_PLAYER_PLAY_FLAG_DOWNLOAD, enabled);
+}
+
+/**
+ * clapper_player_get_download_enabled:
+ * @player: a #ClapperPlayer
+ *
+ * Get whether progressive download buffering is enabled.
+ *
+ * Returns: %TRUE if enabled, %FALSE otherwise.
+ *
+ * Since: 0.8
+ */
+gboolean
+clapper_player_get_download_enabled (ClapperPlayer *self)
+{
+  gboolean enabled;
+
+  g_return_val_if_fail (CLAPPER_IS_PLAYER (self), FALSE);
+
+  GST_OBJECT_LOCK (self);
+  enabled = self->download_enabled;
+  GST_OBJECT_UNLOCK (self);
+
+  return enabled;
+}
+
 /**
  * clapper_player_set_audio_offset:
  * @player: a #ClapperPlayer
@@ -1793,6 +1949,7 @@ clapper_player_thread_start (ClapperThreadedObject *threaded_object)
   for (i = 0; playbin_watchlist[i]; ++i)
     gst_element_add_property_notify_watch (self->playbin, playbin_watchlist[i], TRUE);
 
+  g_signal_connect (self->playbin, "element-setup", G_CALLBACK (_element_setup_cb), self);
   g_signal_connect (self->playbin, "about-to-finish", G_CALLBACK (_about_to_finish_cb), self);
 
   if (!self->use_playbin3) {
@@ -1866,6 +2023,7 @@ clapper_player_init (ClapperPlayer *self)
   self->video_enabled = DEFAULT_VIDEO_ENABLED;
   self->audio_enabled = DEFAULT_AUDIO_ENABLED;
   self->subtitles_enabled = DEFAULT_SUBTITLES_ENABLED;
+  self->download_enabled = DEFAULT_DOWNLOAD_ENABLED;
 }
 
 static void
@@ -1924,6 +2082,8 @@ clapper_player_finalize (GObject *object)
   gst_clear_object (&self->pending_item);
   gst_clear_object (&self->played_item);
 
+  g_free (self->download_dir);
+
   G_OBJECT_CLASS (parent_class)->finalize (object);
 }
 
@@ -1991,6 +2151,12 @@ clapper_player_get_property (GObject *object, guint prop_id,
     case PROP_SUBTITLES_ENABLED:
       g_value_set_boolean (value, clapper_player_get_subtitles_enabled (self));
       break;
+    case PROP_DOWNLOAD_DIR:
+      g_value_take_string (value, clapper_player_get_download_dir (self));
+      break;
+    case PROP_DOWNLOAD_ENABLED:
+      g_value_set_boolean (value, clapper_player_get_download_enabled (self));
+      break;
     case PROP_AUDIO_OFFSET:
       g_value_set_double (value, clapper_player_get_audio_offset (self));
       break;
@@ -2046,6 +2212,12 @@ clapper_player_set_property (GObject *object, guint prop_id,
     case PROP_SUBTITLES_ENABLED:
       clapper_player_set_subtitles_enabled (self, g_value_get_boolean (value));
       break;
+    case PROP_DOWNLOAD_DIR:
+      clapper_player_set_download_dir (self, g_value_get_string (value));
+      break;
+    case PROP_DOWNLOAD_ENABLED:
+      clapper_player_set_download_enabled (self, g_value_get_boolean (value));
+      break;
     case PROP_AUDIO_OFFSET:
       clapper_player_set_audio_offset (self, g_value_get_double (value));
       break;
@@ -2251,6 +2423,52 @@ clapper_player_class_init (ClapperPlayerClass *klass)
       NULL, NULL, DEFAULT_SUBTITLES_ENABLED,
       G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
 
+  /**
+   * ClapperPlayer:download-dir:
+   *
+   * A directory that @player will use to download network content
+   * when [property@Clapper.Player:download-enabled] is set to %TRUE.
+   *
+   * If directory at @path does not exist, it will be automatically created.
+   *
+   * Since: 0.8
+   */
+  param_specs[PROP_DOWNLOAD_DIR] = g_param_spec_string ("download-dir",
+      NULL, NULL, NULL,
+      G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  /**
+   * ClapperPlayer:download-enabled:
+   *
+   * Whether progressive download buffering is enabled.
+   *
+   * If progressive download is enabled and [property@Clapper.Player:download-dir]
+   * is set, streamed network content will be cached to the disk space instead
+   * of memory whenever possible. This allows for faster seeking through
+   * currently played media.
+   *
+   * Not every type of content is download applicable. Mainly applies to
+   * web content that does not use adaptive streaming.
+   *
+   * Once data that media item URI points to is fully downloaded, player
+   * will emit [signal@Clapper.Player::download-complete] signal with a
+   * location of downloaded file.
+   *
+   * Playing again the exact same [class@Clapper.MediaItem] object that was
+   * previously fully downloaded will cause player to automatically use that
+   * cached file if it still exists, avoiding any further network requests.
+   *
+   * Please note that player will not delete nor manage downloaded content.
+   * It is up to application to cleanup data in created cache directory
+   * (e.g. before app exits), in order to remove any downloads that app
+   * is not going to use next time it is run and incomplete ones.
+   *
+   * Since: 0.8
+   */
+  param_specs[PROP_DOWNLOAD_ENABLED] = g_param_spec_boolean ("download-enabled",
+      NULL, NULL, DEFAULT_DOWNLOAD_ENABLED,
+      G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
   /**
    * ClapperPlayer:audio-offset:
    *
@@ -2288,6 +2506,22 @@ clapper_player_class_init (ClapperPlayerClass *klass)
       G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST | G_SIGNAL_NO_RECURSE | G_SIGNAL_NO_HOOKS,
       0, NULL, NULL, NULL, G_TYPE_NONE, 0);
 
+  /**
+   * ClapperPlayer::download-complete:
+   * @player: a #ClapperPlayer
+   * @item: a #ClapperMediaItem
+   * @location: (type filename): a path to downloaded file
+   *
+   * Media was fully downloaded to local cache directory. This signal will
+   * be only emitted when progressive download buffering is enabled by
+   * setting [property@Clapper.Player:download-enabled] property to %TRUE.
+   *
+   * Since: 0.8
+   */
+  signals[SIGNAL_DOWNLOAD_COMPLETE] = g_signal_new ("download-complete",
+      G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST | G_SIGNAL_NO_RECURSE | G_SIGNAL_NO_HOOKS,
+      0, NULL, NULL, NULL, G_TYPE_NONE, 2, CLAPPER_TYPE_MEDIA_ITEM, G_TYPE_STRING);
+
   /**
    * ClapperPlayer::missing-plugin:
    * @player: a #ClapperPlayer

src/lib/clapper/clapper-player.h

@@ -101,6 +101,14 @@ void clapper_player_set_subtitles_enabled (ClapperPlayer *player, gboolean enabl
 
 gboolean clapper_player_get_subtitles_enabled (ClapperPlayer *player);
 
+void clapper_player_set_download_dir (ClapperPlayer *player, const gchar *path);
+
+gchar * clapper_player_get_download_dir (ClapperPlayer *player);
+
+void clapper_player_set_download_enabled (ClapperPlayer *player, gboolean enabled);
+
+gboolean clapper_player_get_download_enabled (ClapperPlayer *player);
+
 void clapper_player_set_audio_offset (ClapperPlayer *player, gdouble offset);
 
 gdouble clapper_player_get_audio_offset (ClapperPlayer *player);