[FFmpeg-trac] #2317(undetermined:new): Byte based seeks fail in chained OGG files (with FLAC codec)
FFmpeg
trac at avcodec.org
Sat Mar 2 12:43:31 CET 2013
#2317: Byte based seeks fail in chained OGG files (with FLAC codec)
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Reporter: gjdfgh | Owner:
Type: defect | Status: new
Priority: normal | Component:
Version: unspecified | undetermined
Keywords: | Resolution:
Blocking: | Blocked By:
Analyzed by developer: 0 | Reproduced by developer: 0
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Comment (by gjdfgh):
You can produce a sample by concatenating two OGG-in-flac files with
"cat". I don't know how to force byte seeks with ffmpeg. With ffplay, the
stream appears to be unseekable even with "-bytes 1". However, doing byte
seeks when using libavformat as library are marked as supported, are
reported as successful, and lead to strange behavior. Please test it
yourself with ffplay (possibly by modifying the code to do byte seeks
properly).
The behavior I'm experiencing is that libavformat does seem to seek to the
correct position (I think it even demuxes some audio packets from the new
position), but then it jumps back. I think it gets confused by the byte
seek, and tries to "resync" to the "correct" (i.e. previous) file position
by explicitly issuing a seek.
Sometimes, it also stops demuxing after printing some errors:
{{{
[ogg @ 0x8a8f120]Cannot identify new stream
[ogg @ 0x8a8f120]failed to create or replace stream
[ogg @ 0x8a8f120]Cannot identify new stream
[ogg @ 0x8a8f120]failed to create or replace stream
}}}
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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2317#comment:2>
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