[MPlayer-users] 1 duplicate frames every 308 seconds :-\

[Jon Fairbairn]

On 2005-07-01 at 16:58EDT Rich Felker wrote:
> On Fri, Jul 01, 2005 at 10:11:36AM +0100, Jon Fairbairn wrote:
> > On 2005-06-30 at 17:56EDT Rich Felker wrote:
> > > On Thu, Jun 30, 2005 at 08:23:43PM +0200, Alain Barthélemy wrote:
> > > > Here is my script:
> > > > 
> > > > mencoder -tv driver=v4l:width=720:height=576 -ovc lavc -lavcopts
> > > > vcodec=mpeg4:vbitrate=2200:vratetol=32000:mbd=2:psnr:aspect=4/3 -oac
> > > > mp3lame -lameopts cbr:br=128:mode=0 -vf
> > > > crop=672:528:24:24,pp=lb,scale=576:432,hqdn3d=3:2:5 -sws 1 -noodml tv://
> > > > -o temp1.avi -endpos 6600 [...]
> > > > What can now happen every 308 seconds?
> > > 
> > > Because your soundcard's clock sucks and is off such that
> > > the error accumulates to a whole frame every 308
> > > seconds...
> > 
> > Why would mencoder do anything with the soundcard?
> 
> Because it's recording sound...

D'oh! Sorry. I forgot that tv cards don't necessarily
provide an audio ADC. Which leads me to wonder whether
the ones that do derive the audio clock from the video.


-- 
Jón Fairbairn                              Jon.Fairbairn at cl.cam.ac.uk