how to apply video-filters with mpegpes output

hello

i tried to use some video-filters like bmovl. if the video
output is on X that works, but if i playback over my DVB
card (-vo mpegpes) then the movie stutters. but this also
occures if i use other filters like -vf scale=720:576 .

so where is the/my problem with filter-chains for mpegpes output?

thanks
lukas

MPlayer-1.0pre7try2, SuSE 10.0, 2.6.14, 2.8GHz