Fix A/V sync when splitting audio and video (kdenlive-2694).

diff --git a/src/modules/avformat/producer_avformat.c b/src/modules/avformat/producer_avformat.c
index 83b3e8adf224076a03dc16ffd1d7a48bc0228a44..8cc9231cdefa6f26fcca53b28a9ab94b7df24426 100644 (file)
--- a/src/modules/avformat/producer_avformat.c
+++ b/src/modules/avformat/producer_avformat.c
@@ -278,6 +278,23 @@ int list_components( char* file )
        return skip;
 }
 
+static int first_video_index( producer_avformat self )
+{
+       AVFormatContext *context = self->video_format? self->video_format : self->audio_format;
+       int i = -1; // not found
+
+       if ( context ) {
+               for ( i = 0; i < context->nb_streams; i++ ) {
+                       if ( context->streams[i]->codec &&
+                            context->streams[i]->codec->codec_type == CODEC_TYPE_VIDEO )
+                               break;
+               }
+               if ( i == context->nb_streams )
+                       i = -1;
+       }
+       return i;
+}
+
 /** Find the default streams.
 */
 
@@ -1041,6 +1058,31 @@ static int64_t best_pts( producer_avformat self, int64_t pts, int64_t dts )
                return dts;
 }
 
+static void find_first_pts( producer_avformat self, int video_index )
+{
+       // find initial PTS
+       AVFormatContext *context = self->video_format? self->video_format : self->audio_format;
+       int ret = 0;
+       int toscan = 500;
+       AVPacket pkt;
+
+       while ( ret >= 0 && toscan-- > 0 )
+       {
+               ret = av_read_frame( context, &pkt );
+               if ( ret >= 0 && pkt.stream_index == video_index && ( pkt.flags & PKT_FLAG_KEY ) )
+               {
+                       mlt_log_debug( MLT_PRODUCER_SERVICE(self->parent),
+                               "first_pts %"PRId64" dts %"PRId64" pts_dts_delta %d\n",
+                               pkt.pts, pkt.dts, (int)(pkt.pts - pkt.dts) );
+                       self->first_pts = best_pts( self, pkt.pts, pkt.dts );
+                       if ( self->first_pts != AV_NOPTS_VALUE )
+                               toscan = 0;
+               }
+               av_free_packet( &pkt );
+       }
+       av_seek_frame( context, -1, 0, AVSEEK_FLAG_BACKWARD );
+}
+
 static int seek_video( producer_avformat self, mlt_position position,
        int64_t req_position, int preseek )
 {
@@ -1064,29 +1106,8 @@ static int seek_video( producer_avformat self, mlt_position position,
                double source_fps = mlt_properties_get_double( properties, "meta.media.frame_rate_num" ) /
                        mlt_properties_get_double( properties, "meta.media.frame_rate_den" );
 
-               // find initial PTS
                if ( self->last_position == POSITION_INITIAL )
-               {
-                       int ret = 0;
-                       int toscan = 500;
-                       AVPacket pkt;
-
-                       while ( ret >= 0 && toscan-- > 0 )
-                       {
-                               ret = av_read_frame( context, &pkt );
-                               if ( ret >= 0 && pkt.stream_index == self->video_index && ( pkt.flags & PKT_FLAG_KEY ) )
-                               {
-                                       mlt_log_debug( MLT_PRODUCER_SERVICE(producer),
-                                               "first_pts %"PRId64" dts %"PRId64" pts_dts_delta %d\n",
-                                               pkt.pts, pkt.dts, (int)(pkt.pts - pkt.dts) );
-                                       self->first_pts = best_pts( self, pkt.pts, pkt.dts );
-                                       if ( self->first_pts != AV_NOPTS_VALUE )
-                                               toscan = 0;
-                               }
-                               av_free_packet( &pkt );
-                       }
-                       av_seek_frame( context, -1, 0, AVSEEK_FLAG_BACKWARD );
-               }
+                       find_first_pts( self, self->video_index );
 
                if ( self->av_frame && position + 1 == self->video_expected )
                {
@@ -2129,6 +2150,15 @@ static int seek_audio( producer_avformat self, mlt_position position, double tim
        // Seek if necessary
        if ( self->seekable && position != self->audio_expected )
        {
+               if ( self->last_position == POSITION_INITIAL )
+               {
+                       int video_index = self->video_index;
+                       if ( video_index == -1 )
+                               video_index = first_video_index( self );
+                       if ( video_index >= 0 )
+                               find_first_pts( self, video_index );
+               }
+
                if ( position + 1 == self->audio_expected )
                {
                        // We're paused - silence required
@@ -2303,6 +2333,9 @@ static int decode_audio( producer_avformat self, int *ignore, AVPacket pkt, int
                                // We are ahead, so seek backwards some more
                                seek_audio( self, req_position, timecode - 1.0 );
                }
+               // Cancel the find_first_pts() in seek_audio()
+               if ( self->video_index == -1 && self->last_position == POSITION_INITIAL )
+                       self->last_position = int_position;
        }
 
        self->audio_used[ index ] = audio_used;