matroskadec: ensure that the timecode added to the index are is the one

of the actual keyframe block, and not the one of the start of the cluster
containing this block.

Originally committed as revision 15229 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/matroskadec.c

@@ -1420,7 +1420,8 @@ static void matroska_clear_queue(MatroskaDemuxContext *matroska)
 
 static int matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data,
                                 int size, int64_t pos, uint64_t cluster_time,
-                                uint64_t duration, int is_keyframe)
+                                uint64_t duration, int is_keyframe,
+                                int64_t cluster_pos)
 {
     MatroskaTrack *track;
     int is_video_key_frame = is_keyframe, res = 0;
@@ -1545,8 +1546,12 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data,
         uint64_t timecode = AV_NOPTS_VALUE;
 
         if (cluster_time != (uint64_t)-1
-            && (block_time >= 0 || cluster_time >= -block_time))
+            && (block_time >= 0 || cluster_time >= -block_time)) {
             timecode = cluster_time + block_time;
+            if (is_keyframe)
+                av_add_index_entry(st, cluster_pos, timecode,
+                                   0, 0, AVINDEX_KEYFRAME);
+        }
 
         for (n = 0; n < laces; n++) {
             if (st->codec->codec_id == CODEC_ID_RA_288 ||
@@ -1641,7 +1646,7 @@ static int matroska_parse_cluster(MatroskaDemuxContext *matroska)
     MatroskaCluster cluster = { 0 };
     EbmlList *blocks_list;
     MatroskaBlock *blocks;
-    int i, res, key_frame = 0;
+    int i, res;
     offset_t pos = url_ftell(matroska->ctx->pb);
     if (matroska->has_cluster_id){
         /* For the first cluster we parse, its ID was already read as
@@ -1659,12 +1664,9 @@ static int matroska_parse_cluster(MatroskaDemuxContext *matroska)
             res=matroska_parse_block(matroska,
                                      blocks[i].bin.data, blocks[i].bin.size,
                                      blocks[i].bin.pos,  cluster.timecode,
-                                     blocks[i].duration, !blocks[i].reference);
-            key_frame |= res > 0;
+                                     blocks[i].duration, !blocks[i].reference,
+                                     pos);
         }
-    if (key_frame)
-        av_add_index_entry(matroska->vstream, pos,
-                           cluster.timecode, 0, 0, AVINDEX_KEYFRAME);
     ebml_free(matroska_cluster, &cluster);
     if (res < 0)  matroska->done = 1;
     return res;