mosaic: drain potential attached pictures coming out of filters

modules/stream_out/mosaic_bridge.c

@@ -586,11 +586,26 @@ static void decoder_queue_video( decoder_t *p_dec, picture_t *p_pic )
     if( p_sys->p_vf2 )
         p_new_pic = filter_chain_VideoFilter( p_sys->p_vf2, p_new_pic );
 
-    /* push the picture in the mosaic-struct structure */
     bridged_es_t *p_es = p_sys->p_es;
-    vlc_global_lock( VLC_MOSAIC_MUTEX );
-    vlc_picture_chain_Append( &p_es->pictures, p_new_pic );
-    vlc_global_unlock( VLC_MOSAIC_MUTEX );
+    if ( p_new_pic != NULL )
+    {
+        vlc_global_lock( VLC_MOSAIC_MUTEX );
+        vlc_picture_chain_Append( &p_es->pictures, p_new_pic );
+        vlc_global_unlock( VLC_MOSAIC_MUTEX );
+    }
+
+    if( p_sys->p_vf2 )
+    {
+        /* push the picture in the mosaic-struct structure */
+        p_new_pic = filter_chain_VideoFilter( p_sys->p_vf2, NULL );
+        while ( p_new_pic != NULL )
+        {
+            vlc_global_lock( VLC_MOSAIC_MUTEX );
+            vlc_picture_chain_Append( &p_es->pictures, p_new_pic );
+            vlc_global_unlock( VLC_MOSAIC_MUTEX );
+            p_new_pic = filter_chain_VideoFilter( p_sys->p_vf2, NULL );
+        }
+    }
 }
 
 static int Send( sout_stream_t *p_stream, void *id, block_t *p_buffer )