[FFmpeg-cvslog] r18959 - in trunk: libavcodec/mpeg12.c tests/seek.regression.ref

Måns Rullgård mans
Mon Jun 15 10:11:41 CEST 2009

Mike Melanson <mike at multimedia.cx> writes:

> Reimar D?ffinger wrote:
>> On Tue, May 26, 2009 at 09:40:46PM -0700, Mike Melanson wrote:
>>> bcoudurier wrote:
>>>> Author: bcoudurier
>>>> Date: Wed May 27 02:14:32 2009
>>>> New Revision: 18959
>>>> Log:
>>>> Fix off by one offset with fetch_timestamps, pts_parser_problem.mpg.
>>>> Patch by Wolfram Gloger, wmglo at dentm dot med dot uni-muenchen dot de.
>>>> Modified:
>>>>    trunk/libavcodec/mpeg12.c
>>>>    trunk/tests/seek.regression.ref
>>> Do you have any idea why this might have broken the pva-demux test?
>>> http://fate.multimedia.cx/index.php?test_spec=298
>>> The file errors out with the following message:
>>> [NULL @ 0x120ab5730]error, non monotone timestamps 50151 >= 42951
>>> av_interleaved_write_frame(): Error while opening file
>> I don't like it much, but since FATE staying broken or disabling the
>> test seems even worse:
>> How about changing the test to be based on the
>> http://samples.mplayerhq.hu/PVA/_B5_Crusade_-_Kosmiczna_Krucjata_01pl_1276.pva
>> or
>> http://samples.mplayerhq.hu/PVA/_Babylon_5_5x01pl_1251.pva
>> sample?
>> That leaves 5/7 of our sample files broken but better than nothing...
> I started testing the samples and noticed that all 7 appear to work
> just fine. Then I noticed that I omitted the "-acodec copy -vcodec
> copy" options. So everything is okay when decoding the audio and video.

Yes, timestamp oddities are more prevalent with -?codec copy.

> Solution: Omit the "-vcodec copy" option (the MP2 is also decoding bit
> exact across platforms, but I don't trust that) and start decoding the
> video, though with the "-idct simple" option which is supposed to be
> bit exact across platforms and compilers.

Not a solution, only a workaround.

> New problem: Bit exactness is not maintained across platforms (PPC
> differs from x86_32/64).
> Solution: Cheat and only decode some of the sample, just before
> problems are known to set in:
> $BUILD_PATH/ffmpeg -idct simple -i
> $SAMPLES_PATH/pva/PVA_test-partial.pva -t 0.6 -acodec copy -f framecrc -
> Hopefully, this solves this longstanding testing discrepancy satisfactorily.

It is still hiding the fact that there's a bug there somewhere.  This
used to work, and now it does not.  Ergo, something broke.

M?ns Rullg?rd
mans at mansr.com

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