[ogg-dev] possible regression in libogg

Oleksij Rempel linux at rempel-privat.de
Tue Dec 3 23:32:34 PST 2013

Am 03.12.2013 23:49, schrieb Monty Montgomery:
> Any time code is stuck in a loop calling ogg_sync_pageseek() or
> ogg_sync_pageout(), you'll see most of the time sunk into checksum
> calculation.  It's the only thing in libogg that _can_ take much time.
>  This is not likely a libogg bug, but a bug in the code calling libogg
> in a tight loop.
> Looking at the file listed in the bug, there's a page discontinuity at
> the very beginning; after the header packets/pages, there are several
> missing pages before data starts normally.  Whatever generated or
> trimmed this file did a ragged job at the beginning.

This file was generated long time ago. Not sure for 100% but it was
gstreamer + OggIndex. may be ffmpeg2theora.

> This isn't an
> error, strictly speaking, but it's not completely correct either.
> First thing I'd check is whether or not this has tripped up the
> seeking code in gstreamer...  Or actually, _any_ kind of analysis of
> what gstreamer is actually doing.

ok. If you do not mind  i'll repost you message in the bug.

> A profiler is not a debugger!  It's just waving a dead chicken at this
> problem, then trying to read the tea leaves.  As of yet we have no
> concrete evidence of what is happening aside from gstreamer
> calculating a ton of Ogg checksums.
> Monty


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