[MEncoder-users] Puzzle - Frame skipping and audio

[Joseph Eoff]

Hi.

I've found that mencoder works really well for digitizing the tapes from 
my analog video camera.  With the cropping and deinterlacing mencoder 
does, the resulting clips look really good on the computer screen.

I recently bought a new digitizer - the old one was ten years old and 
just gave up the ghost.  The new digitizer connects via USB and has a 
built in sound card.  I would rather connect all of my video camera 
cables to just the digitizer box instead of connectig the video the 
digitizer and the audio to my sound card, so I changed my normal 
configuration to use the new sound card instead of taking the default 
and using the sound card built into the computer.

Recording with the sound card explicitly set causes frame skips - LOTS 
of frame skips, to the point that the resulting video is completely useless.

At first I thought is was a problem with the new digitizer, but the same 
thing happens if I specify the sound card built into the computer.

The normal capture looks like this:
mencoder -tv 
driver=v4l2:width=720:height=576:input=2:outfmt=i420:norm=pal:immediatemode=0:forceaudio 
-oac mp3lame -lameopts cbr:br=128 -mc 0 -ovc lavc -lavcopts 
vcodec=mpeg4:vbitrate=8000 -vf crop=700:542:12:16,pp=lb,harddup -o 
capture.avi tv://

That command uses the new video digitizer on /dev/video0 and the sound 
card built into the computer.
mencoder -tv 
driver=v4l2:width=720:height=576:input=2:buffersize=256:outfmt=i420:norm=pal:immediatemode=0:forceaudio 
-oac mp3lame -lameopts cbr:br=128 -mc 0 -ovc lavc -lavcopts 
vcodec=mpeg4:vbitrate=8000 -vf crop=700:542:12:16,pp=lb,harddup -o 
capture.avi tv://

This one explicitly sets the same audio source, but skips like mad and 
produces a completely unusable video:
mencoder -tv 
driver=v4l2:width=720:height=576:input=2:buffersize=256:outfmt=i420:norm=pal:alsa:adevice=hw.0:immediatemode=0:forceaudio 
-oac mp3lame -lameopts cbr:br=128 -mc 0 -ovc lavc -lavcopts 
vcodec=mpeg4:vbitrate=8000 -vf crop=700:542:12:16,pp=lb,harddup -o 
capture.avi tv://

Does anyone see what I'm doing wrong to make mencoder skip when 
explicitly setting the audio source?

Joseph Eoff