lavf/flvdec: Allow files where the PreviousTagSize is not set accordi…

…ng to the spec. Some muxer use the FLV field PreviousTagSize to be the sum of tag length. Without this change, the flv demuxer think the file is broken and the re-sync will fail. Signed-off-by: Michael Niedermayer <[email protected]>
vacing · Jan 29, 2016 · 9a09952 · 9a09952
1 parent 583a643
commit 9a09952
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
@@ -60,6 +60,7 @@ typedef struct FLVContext {
     uint8_t resync_buffer[2*RESYNC_BUFFER_SIZE];
 
     int broken_sizes;
+    int sum_flv_tag_size;
 } FLVContext;
 
 static int probe(AVProbeData *p, int live)
@@ -629,6 +630,7 @@ static int flv_read_metabody(AVFormatContext *s, int64_t next_pos)
 static int flv_read_header(AVFormatContext *s)
 {
     int offset, flags;
+    FLVContext *flv = s->priv_data;
 
     avio_skip(s->pb, 4);
     flags = avio_r8(s->pb);
@@ -649,6 +651,7 @@ static int flv_read_header(AVFormatContext *s)
     avio_skip(s->pb, 4);
 
     s->start_time = 0;
+    flv->sum_flv_tag_size = 0;
 
     return 0;
 }
@@ -857,6 +860,7 @@ static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
         type = (avio_r8(s->pb) & 0x1F);
         orig_size =
         size = avio_rb24(s->pb);
+        flv->sum_flv_tag_size += size + 11;
         dts  = avio_rb24(s->pb);
         dts |= (unsigned)avio_r8(s->pb) << 24;
         av_log(s, AV_LOG_TRACE, "type:%d, size:%d, last:%d, dts:%"PRId64" pos:%"PRId64"\n", type, size, last, dts, avio_tell(s->pb));
@@ -1141,7 +1145,7 @@ static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
 leave:
     last = avio_rb32(s->pb);
     if (last != orig_size + 11 &&
-        (last != orig_size || !last) &&
+        (last != orig_size || !last) && last != flv->sum_flv_tag_size &&
         !flv->broken_sizes) {
         av_log(s, AV_LOG_ERROR, "Packet mismatch %d %d\n", last, orig_size + 11);
         avio_seek(s->pb, pos + 1, SEEK_SET);