since you are most probably recording on the mpeg2 format, it is but normal for you to have big file sizes for a movie, around 3 gigs per hour i think? the file size is determined by the lenght of your movie being captured and the bitrate you used on it. now, there are some calculators for that, like powerbit. then also, you should be able to customise your capture profiles basing on the bitrates you specify and from that, you can expect how big your mpeg2 file will be after recording. now, to shrink the mpeg2 file, you may convert that to other formats, like divx if you like. divx offers good compression with minimal distortions and loss in quality. i really doubt though if you can stream and convert at real time since that would take a lot of cpu power from your box.