I am trying to use video capture and playback on a 700MHz K7 processor. I have a capture card with hardware mpeg-2 encoding, and a video card that at least claims to support hardware mpeg-2 decoding (nv mx 4000) so that my CPU does very little work. However, when I try to watch live video from the capture card, my CPU usage maxes out and the video lags the audio by an ever-increasing margin. I am trying to watch the video using mplayer and think that software prescaling may be at fault. MPlayer outputs:

Movie_Aspect is 1.33:1 - prescaling to correct movie aspect.
VO: [xv] 720x480 => 720x520 Planar YV12

I have tried setting the scale to 720x480 so that it won't scale with no luck. I don't see any indication in the man page of how to turn this off, although I may have missed it... it's a pretty big page. Any suggestions of how to do this? Thanks.