[Ffmpeg-devel] [BUG] converting mpeg4/mp3 to mpeg2video/mp3

[Michael Niedermayer]

Hi

On Mon, Nov 13, 2006 at 12:20:21PM -0500, Cyrus A wrote:
> Cyrus A wrote:
> >I have encountered a problem trying to reencode an mpeg4/mp3 avi into 
> >an mpeg2video/mp3 mpg file.
> >
> >The original MPEG-4 file is captured from an ivtv video capture device 
> >with the following command:
> >
> >[cyrus at wkyt ffmpeg_6967]$ ./ffmpeg -i /dev/video0 -async 1 -y -vcodec 
> >mpeg4 -acodec mp3 -t 2080 -b 1750k -ab 192 -ar 44100 -s 480x384 -vtag 
> >DX50 '/usr/local/apache-tomcat/webapps/ROOT/test_for_ffmpeg-devel.avi'
> >FFmpeg version SVN-r6967, Copyright (c) 2000-2006 Fabrice Bellard, et al.
> > configuration:  --enable-mp3lame
> > libavutil version: 49.0.2
> > libavcodec version: 51.25.0
> > libavformat version: 51.6.0
> > built on Nov 11 2006 00:00:13, gcc: 4.1.1 20060525 (Red Hat 4.1.1-1)
> >Input #0, mpeg, from '/dev/video0':
> > Duration: N/A, bitrate: 9984 kb/s
> > Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x480, 9600 kb/s, 
> >29.97 fps(r)
> > Stream #0.1[0x1c0]: Audio: mp2, 48000 Hz, stereo, 384 kb/s
> >Output #0, avi, to 
> >'/usr/local/apache-tomcat/webapps/ROOT/test_for_ffmpeg-devel.avi':
> > Stream #0.0: Video: mpeg4, yuv420p, 480x384, q=2-31, 1750 kb/s, 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
> >[mp3 @ 0x964210]lame: output buffer too small (buffer index: 592, free 
> >bytes: 1712)
> >frame=  304 q=3.6 Lsize=    2570kB time=10.1 bitrate=2077.0kbits/s   
> >video:2258kB audio:238kB global headers:0kB muxing overhead 2.975545%
> >
> >The resulting avi file can be downloaded here: 
> >http://wkyt.dynalias.com/test_for_ffmpeg-devel.avi . As you can see, 
> >the file looks good and plays perfectly.
> >
> >The mpeg2video command I've been using (among others is):
> >
> >[cyrus at wkyt ffmpeg_6967]$ ./ffmpeg -v 0 -b 600 -y  -i 
> >/usr/local/jakarta-tomcat/webapps/ROOT/test_for_ffmpeg-devel.avi 
> >-acodec mp3 -vcodec mpeg2video 
> >/usr/local/jakarta-tomcat/webapps/ROOT/test_for_ffmpeg-devel.mpg
> >FFmpeg version SVN-r6967, Copyright (c) 2000-2006 Fabrice Bellard, et al.
> > configuration:  --enable-mp3lame
> > libavutil version: 49.0.2
> > libavcodec version: 51.25.0
> > libavformat version: 51.6.0
> > built on Nov 11 2006 00:00:13, gcc: 4.1.1 20060525 (Red Hat 4.1.1-1)
> >
> >Seems that stream 0 comes from film source: 30000.00 (30000/1) -> 
> >29.97 (30000/1001)
> >Stream mapping:
> > Stream #0.0 -> #0.0
> > Stream #0.1 -> #0.1
> >Press [q] to stop encoding
> >invalid new backstep 590
> >invalid new backstep 591
> >invalid new backstep 591
> >invalid new backstep 591
> >invalid new backstep 591
> >invalid new backstep 591
> >invalid new backstep 591
> >invalid new backstep 591
> >invalid new backstep 591
> >invalid new backstep 591
> >invalid new backstep 591
> >invalid new backstep 591
> >invalid new backstep 591
> >frame=  292 q=31.0 Lsize=     560kB time=9.7 bitrate= 472.5kbits/s   
> >video:476kB audio:77kB global headers:0kB muxing overhead 1.267253%
> >
> >Obviously, the invalid new backstep stuff is troubling. The resulting 
> >file can be found here:
> >http://wkyt.dynalias.com/test_for_ffmpeg-devel.mpg
> >
> >As you may notice, the resulting mpg file plays perfectly in mplayer 
> >(and probably other open-source players I haven't tested). The problem 
> >is that the image gets all screwy when played in windows. You can 
> >still hear the audio, but the video goes psychedelic. I know most of 
> >you have the luxury of not using windows as I wish I could, but the 
> >users of my web applications do and therefore these files must play 
> >correctly in WMP. (I tried to do a screen capture, but the video area 
> >was blank.)
> >
> >For testing in windows, try 
> >http://wkyt.dynalias.com/test_for_ffmpeg-devel.html . It has the DivX 
> >web player plugin code embedding and a link for downloading the mpg 
> >with a right-click.
> >
> >I have tested a ton of ffmpeg revisions on this. The first revision 
> >that will compile on my machine (64-bit 2.6.18 kernel) was revision 
> >4019 which produces a serious video delay sync issue for the avi. 
> >Other revisions do strange things as well: 4526 produces an avi that 
> >skips/chirps at the end when played in the DivX web player. 4800 
> >produces a good avi, but the mpg is either blank (when reencoded with 
> >4800) or back to psychedelic (when reencoded with 6967). I also 
> >sporadically tried 4300 and 6801 in combination with the other 
> >revisions but nothing would work properly.
> >
> >I'm kind of at the mercy of the wizards on this mailing list to take a 
> >look and fix the bug, or if there isn't a bug, tell me what I'm doing 
> >wrong.
> >
> >As always, your help is greatly appreciated.
> >
> >Cyrus
> >
> >
> >_______________________________________________
> >ffmpeg-devel mailing list
> >ffmpeg-devel at mplayerhq.hu
> >http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel
> A little more information on this:
> 
> I'm able to convert the SVN-created mpeg4/mp3 avi into working WMV and 
> MPEG-2 files using a program called Digital Media Converter (DMC) on 
> windows.
> 
> Also, I tried to take the SVN-created mpeg4/mp3 and reencode it on a 
> 32-bit computer with an old version of ffmpeg and got bad results. The 
> audio and video would start out in sync, but over time (clearly 
> noticeable after 10 seconds) the video would get behind the audio and 
> steadily get worse.
> 
> I still don't know if the problem is with the original recording of the 
> mpeg4/mp3 avi (although these files play perfectly in windows and with 
> mplayer) or the reencoding from mpeg4/mp3 avi to mpeg2video/mp3 mpg.
> 
> Again, any help, any advice on what else I can do to test... any insight 
> whatsoever... would be helpful.

looking at this again, theres something ive missed at first, you generate
VBR mpeg1, microsoft does not support that AFAIK, try CBR

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is