[Ffmpeg-devel] closed captioning bug?

[Cyrus A]

Luca Abeni wrote:
> Hi,
>
> On Sun, 2006-04-23 at 23:50 -0400, Cyrus A wrote:
> [...]
>   
>> More info here: I downgraded (wiped and reinstalled) to FC3. An old 
>> version of ffmpeg (probably early 2005) seems to work (at least for a 
>> while) when trying to capture closed captions.*
>>     
> I know this is a lot of work, but can you try a dichotomic search to
> find out which commit is responsible for the breakage you are seeing?
> My experience is that this commit
> http://www1.mplayerhq.hu/cgi-bin/cvsweb.cgi/ffmpeg/ffmpeg.c.diff?r1=1.225&r2=1.226&cvsroot=FFMpeg
> might cause problems when capturing audio and video simultaneously
> (note: the commit is perfectly fine and correct. The problem is that the
> grab.c and audio.c inputs are a little bit "special").
> But if early 2005 works ok for you this commit is not the problem...
>
> [...]
>   
>> * The caps will work fine for up to 5 minutes (maybe more) with ffmpeg 
>> driving /dev/audio and /dev/video0. However, they eventually get garbled 
>> again for some reason. Maybe the caps go bad when I use my USB KVM 
>> switch? I have no idea. I'm going to try doing them without KDE or GNOME 
>> running and no USB switching over the next 24 hours. We'll see how they 
>> turn out.
>>     
> I think the output of "dmesg" and "lsmod" could be useful for finding
> the problem.
>
> Also,try execution ffmpeg alone (without closed captioning) but adding
> "-v 5" to the command line, and see if duplicated/dropped frames are
> reported.
>
> 				Luca
>   
Thanks for the help. After applying the patch, config.h did not include 
the VIDEO4LINUX2 line you thought it would.

My dmesg output:

bttv0: PLL can sleep, using XTAL (28636363).
application ffmpeg uses obsolete OSS audio interface
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*
bttv0: SCERR @ 3f660014,bits: OFLOW FDSR SCERR*

I don't know that ffmpeg has actually ever worked on this x86_64 system, 
so it would be hard to find one that did. I'll get back to you on it. In 
the meantime, how do we get v4l2 to get recognized by ffmpeg on this 
darn machine?

For the version tests, unfortunately I'm getting a lot of compile 
errors, probably because of something I'm doing incorrectly.

1/7/06 revision 1.362 caps screwed up
5/27/06 revision 1.336 compile error
1/4/05 revision 1.298 compile error
1/1/04 revision 1.172 compile error

Cyrus

p.s. For these version tests, which options should I use? --cpu=x86_64 
--cc=/usr/bin/gcc33  ??? Otherwise I have to try several combinations on 
each version which will take FOREVER. And all I'm doing is replacing 
ffmpeg.c each time. Is that ok or do I need the whole package. If so, 
how do I download the whole package for each version?