[Ffmpeg-devel] corrupt audio when cut

[Cyrus A]

Wolfram Gloger wrote:
> Hi,
>
>   
>> Unfortunately, the patch actually made things worse. The "error, non 
>> monotone timestamps" stuff was still there on the 16,48,80 (problematic) 
>> values and the audio was still messed up.
>>     
>
> That is very strange!  I have just verified with "test.avi" downloaded
> this morning (md5: 27ae5c7454f9c7960e5a508a3f41006a):
>
> Without the patch, I can reproduce your problems exactly.
>
> With the patched version, I get (note especially the "after seek
> timestamp" message):
>
> % /tmp/ffmpeg/ffmpeg -ss 48.0 -t 25.8 -y -vcodec copy -acodec copy -i test.avi cutfile.avi
> FFmpeg version SVN-r7541, Copyright (c) 2000-2006 Fabrice Bellard, et al.
>   configuration:  --enable-a52 --enable-mp3lame --enable-gpl --enable-libogg --enable-vorbis 
>   libavutil version: 49.1.0
>   libavcodec version: 51.28.0
>   libavformat version: 51.7.0
>   built on Jan 16 2007 11:04:22, gcc: 2.95.4 20011002 (Debian prerelease)
> tag: tag=LIST size=0x2276
> ...
> tag: tag=LIST size=0x4cf802
> list: tag=movi size=0x0
> movi end=4d1eb4
> movi_end=0x4d1eb4
> tag=idx1 size=0x16ad0
> *** after seek timestamp= 48014633
>
> Seems stream 0 codec frame rate differs from container frame rate: 30000.00 (30000/1) -> 29.97 (30000/1001)
> Input #0, avi, from 'test.avi':
>   Duration: 00:01:25.0, start: 0.000000, bitrate: 484 kb/s
>   Stream #0.0: Video: mpeg4, yuv420p, 480x384, 29.97 fps(r)
>   Stream #0.1: Audio: mp3, 44100 Hz, stereo, 192 kb/s
> Output #0, avi, to 'cutfile.avi':
>   Stream #0.0: Video: mpeg4, yuv420p, 480x384, q=2-31, 29.97 fps(c)
>   Stream #0.1: Audio: mp3, 44100 Hz, stereo, 192 kb/s
> Stream mapping:
>   Stream #0.0 -> #0.0
>   Stream #0.1 -> #0.1
> Press [q] to stop encoding
> frame=  774 q=1181175.9 Lsize=    1515kB time=25.8 bitrate= 480.9kbits/s    
> video:858kB audio:604kB global headers:0kB muxing overhead 3.575189%
>
> And the resulting file is fine AFAICS, no corruption.
>
>   
>> Furthermore, non-problematic 
>> values caused ffmpeg to *transcode* from test.avi into cutfile.avi 
>> instead of just cutting. Whereas before the cut command was almost 
>> instantaneous (which makes sense under the -acodec copy -vcodec copy 
>> conditions), the patched ffmpeg now takes much, much longer as if I were 
>> transcoding from one format to another.
>>     
>
> That is practically impossible given the non-intrusiveness of the
> patch.  I tried "non-problematic" start values as well and everything
> is fine..  Please try again, something must have gone terribly wrong
> while applying the patch.
>
> Regards,
> Wolfram.
> _______________________________________________
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> ffmpeg-devel at mplayerhq.hu
> http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel
>   
I'm a bigtime newbie to development at this low-level, i.e. I'm not 
exactly sure how to apply patches. Here's what I did. Tell me if I did 
it wrong.

I first got the most recent svn to my home directory.  Then, I copied 
the patch file to my home directory. I used the command "patch -p0 < 
patch.diff" to apply the patch, then ran configure --enable-mp3lame and 
then make.

Is that right?

Cyrus