#8686: mpegts unexpected "Unable to seek back to the start"
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Reporter: dista | Type: defect
Status: new | Priority: normal
Component: avformat | Version: git-master
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Input is mpegts over srt stream, sometimes it logs "Unable to seek back
to the start" in the beginning.
After debugging, I think it is caused by mpegts.c's get_packet_size()
function.
here is what happend:
1. it call avio_read_partial(), and get 1316 bytes
2. it calculate score=7, dvhs=2(maybe some 0x47 in middle),fec_score=2
3. because score(7) == margin(2+5), it need to go to next round
4. it call avio_read_partial(), but in that function "len=s->buf_end -
s->buf_ptr" just equals 0, so it run "s->buf_end = s->buf_ptr =
s->buffer", after that the data in buffer is dropped.
5. after that, it will call seek_back(), and because we dropped data in
buffer, we can not seek back.
I can remove "s->buf_end = s->buf_ptr = s->buffer" in avio_read_partial()
to fix this problem, but it may break other things.
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Ticket URL: <https://trac.ffmpeg.org/ticket/8686>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
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