Merge pull request #599 from Rafostar/framestepping

clapper: Implement frame advance function

src/bin/clapper-app/clapper-app-window.c

@@ -883,6 +883,18 @@ _handle_speed_key_press (ClapperAppWindow *self, gboolean forward)
       (forward) ? "av.speed-up" : "av.speed-down", NULL);
 }
 
+static void
+_handle_advance_frame_key_press (ClapperAppWindow *self)
+{
+  ClapperPlayer *player = clapper_gtk_av_get_player (
+      CLAPPER_GTK_AV_CAST (self->video));
+  ClapperPlayerState state = clapper_player_get_state (player);
+
+  /* Do not try to advance frame when stopped or buffering */
+  if (state >= CLAPPER_PLAYER_STATE_PAUSED)
+    clapper_player_advance_frame (player);
+}
+
 static inline void
 _handle_progression_key_press (ClapperAppWindow *self)
 {
@@ -939,6 +951,10 @@ key_pressed_cb (GtkEventControllerKey *controller, guint keyval,
       if ((state & GDK_MODIFIER_MASK) == 0)
         _handle_seek_key_press (self, TRUE);
       break;
+    case GDK_KEY_e:
+      if ((state & GDK_MODIFIER_MASK) == 0)
+        _handle_advance_frame_key_press (self);
+      break;
     case GDK_KEY_space:
     case GDK_KEY_k:
       if (!self->key_held && (state & GDK_MODIFIER_MASK) == 0)

src/bin/clapper-app/ui/clapper-app-help-overlay.ui

@@ -190,6 +190,16 @@
                 <property name="accelerator">less</property>
               </object>
             </child>
+            <child>
+              <object class="GtkShortcutsShortcut">
+                <property name="title" translatable="yes">Advance frame</property>
+                <property name="accelerator">e</property>
+              </object>
+            </child>
+          </object>
+        </child>
+        <child>
+          <object class="GtkShortcutsGroup">
             <child>
               <object class="GtkShortcutsShortcut">
                 <property name="direction">ltr</property>

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

@@ -43,6 +43,8 @@ void clapper_playbin_bus_post_seek (GstBus *bus, gdouble position, ClapperPlayer
 
 void clapper_playbin_bus_post_rate_change (GstBus *bus, gdouble rate);
 
+void clapper_playbin_bus_post_advance_frame (GstBus *bus);
+
 void clapper_playbin_bus_post_stream_change (GstBus *bus);
 
 void clapper_playbin_bus_post_current_item_change (GstBus *bus, ClapperMediaItem *current_item, ClapperQueueItemChangeMode mode);

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

@@ -41,6 +41,7 @@ enum
   CLAPPER_PLAYBIN_BUS_STRUCTURE_SET_PLAY_FLAG,
   CLAPPER_PLAYBIN_BUS_STRUCTURE_SEEK,
   CLAPPER_PLAYBIN_BUS_STRUCTURE_RATE_CHANGE,
+  CLAPPER_PLAYBIN_BUS_STRUCTURE_ADVANCE_FRAME,
   CLAPPER_PLAYBIN_BUS_STRUCTURE_STREAM_CHANGE,
   CLAPPER_PLAYBIN_BUS_STRUCTURE_CURRENT_ITEM_CHANGE,
   CLAPPER_PLAYBIN_BUS_STRUCTURE_ITEM_SUBURI_CHANGE,
@@ -53,6 +54,7 @@ static ClapperBusQuark _structure_quarks[] = {
   {"set-play-flag", 0},
   {"seek", 0},
   {"rate-change", 0},
+  {"advance-frame", 0},
   {"stream-change", 0},
   {"current-item-change", 0},
   {"item-suburi-change", 0},
@@ -568,6 +570,42 @@ _handle_rate_change_msg (GstMessage *msg, const GstStructure *structure, Clapper
   }
 }
 
+void
+clapper_playbin_bus_post_advance_frame (GstBus *bus)
+{
+  GstStructure *structure = gst_structure_new_id_empty (_STRUCTURE_QUARK (ADVANCE_FRAME));
+  gst_bus_post (bus, gst_message_new_application (NULL, structure));
+}
+
+static inline void
+_handle_advance_frame_msg (GstMessage *msg, const GstStructure *structure, ClapperPlayer *player)
+{
+  GstEvent *step_event;
+
+  /* If we are starting playback or pipeline is going
+   * to be stopped, ignore advance frame operation */
+  if (player->current_state < GST_STATE_PAUSED
+      || player->target_state < GST_STATE_PAUSED)
+    return;
+
+  /* Pause playback for frame stepping */
+  if (player->target_state != GST_STATE_PAUSED) {
+    player->target_state = GST_STATE_PAUSED;
+    gst_element_set_state (player->playbin, player->target_state);
+  }
+
+  step_event = gst_event_new_step (GST_FORMAT_BUFFERS, 1, 1.0, TRUE, FALSE);
+  GST_DEBUG_OBJECT (player, "Advancing frame");
+
+  clapper_player_remove_tick_source (player);
+
+  if (!(player->stepping = gst_element_send_event (player->playbin, step_event))) {
+    /* FIXME: Should we maybe call _handle_error_msg with
+     * some error here? Or will playbin post such message for us? */
+    GST_ERROR_OBJECT (player, "Could not advance frame");
+  }
+}
+
 static inline void
 _handle_state_changed_msg (GstMessage *msg, ClapperPlayer *player)
 {
@@ -904,6 +942,8 @@ _handle_app_msg (GstMessage *msg, ClapperPlayer *player)
     _handle_seek_msg (msg, structure, player);
   else if (quark == _STRUCTURE_QUARK (RATE_CHANGE))
     _handle_rate_change_msg (msg, structure, player);
+  else if (quark == _STRUCTURE_QUARK (ADVANCE_FRAME))
+    _handle_advance_frame_msg (msg, structure, player);
   else if (quark == _STRUCTURE_QUARK (STREAM_CHANGE))
     _handle_stream_change_msg (msg, structure, player);
   else if (quark == _STRUCTURE_QUARK (CURRENT_ITEM_CHANGE))
@@ -1216,6 +1256,11 @@ _handle_async_done_msg (GstMessage *msg G_GNUC_UNUSED, ClapperPlayer *player)
     clapper_app_bus_post_simple_signal (player->app_bus,
         GST_OBJECT_CAST (player), signal_id);
   }
+  if (player->stepping) {
+    player->stepping = FALSE;
+    GST_DEBUG_OBJECT (player, "Frame advanced");
+    clapper_player_refresh_position (player);
+  }
   if (player->speed_changing) {
     if (player->pending_speed != 0) {
       GST_DEBUG_OBJECT (player, "Changing rate to pending value: %.2lf -> %.2lf",

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

@@ -87,6 +87,7 @@ struct _ClapperPlayer
   gboolean use_playbin3; // when using playbin3
   gboolean had_error; // so we do not do stuff after error
   gboolean seeking; // during seek operation
+  gboolean stepping; // during frame step operation
   gboolean speed_changing; // during rate change operation
   gboolean pending_eos; // when pausing due to EOS
   gboolean pending_flush; // after another stream selection

src/lib/clapper/clapper-player.c

@@ -2195,6 +2195,24 @@ clapper_player_seek_custom (ClapperPlayer *self, gdouble position, ClapperPlayer
   clapper_playbin_bus_post_seek (self->bus, position, method);
 }
 
+/**
+ * clapper_player_advance_frame:
+ * @player: a #ClapperPlayer
+ *
+ * Request the player to perform a frame step operation.
+ *
+ * Note that this will pause playback automatically.
+ *
+ * Since: 0.10
+ */
+void
+clapper_player_advance_frame (ClapperPlayer *self)
+{
+  g_return_if_fail (CLAPPER_IS_PLAYER (self));
+
+  clapper_playbin_bus_post_advance_frame (self->bus);
+}
+
 /**
  * clapper_player_add_feature:
  * @player: a #ClapperPlayer

src/lib/clapper/clapper-player.h

@@ -204,6 +204,9 @@ void clapper_player_seek (ClapperPlayer *player, gdouble position);
 CLAPPER_API
 void clapper_player_seek_custom (ClapperPlayer *player, gdouble position, ClapperPlayerSeekMethod method);
 
+CLAPPER_API
+void clapper_player_advance_frame (ClapperPlayer *player);
+
 CLAPPER_API
 void clapper_player_add_feature (ClapperPlayer *player, ClapperFeature *feature);