[MPlayer-users] record from TV ( v4l ) with sound

[Emmanuel Anne]

On Tue, 22 Oct 2002, Jindrich Makovicka wrote:

> The reason is that the timebases of CPU and soundcard are different. It 
> means that per one second of CPU time the soundcard doesn't deliver 
> 44100 samples but some more or less. So after some time, there is a lack 
> or excess of samples and mencoder has to deal with this and it does that 
> by inserting an empty frame. There's actually no frame lost.

Ok, I was not clear enough obviously. What I mean by "drop frames" is
that I get some "jumpiness" in the animation - the animation is not
smooth and not 25fps, more like 15fps.
Also if I capture the video from the console with DEBUG=2 in the zoran
driver then I clearly see the dropped frames on the console. You get
something like :
<zoran info><mplayer info> -> good frame
<zoran info> (no mplayer info) -> droped frame
...

It does not drop half the frames, but it's hard to say exactly how much
are droped. I'll try the -v switch to see if mencoder knows it looses
these frames, but I don't think so. By the way the sound is perfect once
you force mencoder to use /dev/dsp for it (even if it does not seem to
know anything about synchronisation - you see A/V 0.000 while
recording).

Until I find a solution for this, I am using the hardware capture
capability of lavrec to capture the stream in mjpeg - 25fps. No frame
droped, but the file is really really huge !
 
> Regarding the sound problem, I could add an option, say, "force-audio" 
> which will just force grabbing from the audio source.

Yeah, it would be helpfull, and nicer than what I did, surely !
 
> I'll try to update the v4l docs, if I'll have some spare time.
> 
> Regards,

Thanks !
 
> -- 
> Jindrich Makovicka