refer to SPEC:
Annex E. The FLV File Format said:
E.3 TheFLVFileBody have a table:
Field Type Comment
PreviousTagSize0 UI32 Always 0
Reviewed-by: Bela Bodecs <bodecsb@vivanet.hu>
Reviewed-by: Hendrik Leppkes <h.leppkes@gmail.com>
Signed-off-by: Steven Liu <lq@chinaffmpeg.org>
int flags;
FLVContext *flv = s->priv_data;
int offset;
+ int pre_tag_size = 0;
avio_skip(s->pb, 4);
flags = avio_r8(s->pb);
offset = avio_rb32(s->pb);
avio_seek(s->pb, offset, SEEK_SET);
- avio_skip(s->pb, 4);
+
+ /* Annex E. The FLV File Format
+ * E.3 TheFLVFileBody
+ * Field Type Comment
+ * PreviousTagSize0 UI32 Always 0
+ * */
+ pre_tag_size = avio_rb32(s->pb);
+ if (pre_tag_size) {
+ av_log(s, AV_LOG_WARNING, "Read FLV header error, input file is not a standard flv format, first PreviousTagSize0 always is 0\n");
+ }
s->start_time = 0;
flv->sum_flv_tag_size = 0;