[MEncoder-users] losing audio sync during video capture

[DaveG]

Any suggestions or link pointers on how to get around losing audio sync during 
video capture?

FreeBSD 7.1

bktr0: <BrookTree 878> mem 0xe8005000-0xe8005fff irq 17 at device 8.0 on pci0
bktr0: [GIANT-LOCKED]
bktr0: [ITHREAD]
bktr0: Hauppauge Model 44805 D111
bktr0: Hauppauge WinCast/TV, Philips PAL I tuner.

MEncoder 1.0rc2-4.2.1 (C) 2000-2007 MPlayer Team
CPU: Intel(R) Pentium(R) 4 CPU 3.20GHz (Family: 15, Model: 3, Stepping: 4)
CPUflags: Type: 15 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1

#!/bin/sh
length="-endpos 00:11:00"
outfile=/home9/camcorder/camcorder.avi
audio="-oac mp3lame -lameopts cbr:br=128"
filter="-vf pp=lb,crop=738:560:16:8,scale=738:290"
bitrate="vbitrate=8000"
video="-fps 25 -ovc lavc -lavcopts vcodec=mpeg4:ildct:ilme:vhq:keyint=250"
mencoder -noskip -mc 0 tv://0 ${length} ${filter} ${video}:${bitrate} /
                 ${audio} -of avi -ffourcc DX50 -o ${outfile}

While capturing, framerate gets up to 24.9fps.  Sound is lagging by at least 
0.5s within 60s of playback.

Should I be trying to "fix" the above command line or trying some other codec?  
Do I need a better capture card?

Ideally I'd like the output file to be in DV for editing in kino but I can't 
get past the problem of two streams being required.   Googling for dv 
encoding points to using -tv options such as amode=1, forceaudio etc. but 
mencoder, despite having amode and forceaudio in the man page mencoder 
insists it doesn't understand those options.

Do you need any other info to help me out/point me in the right direction?

-- 
Dave