Its kind of the whole point that a video is compressed when it is converted to play online. Otherwise it would not stream (IE it would play quicker than it downloads - causing stop/start effect) very well. It does seem that it compresses some videos better than it does others. At a guess (as I haven't tried) I'd say that the better you compress it on your own computer (xvid or divx) the less compression and 'figuring out' trialstube has to do, and you'll end up with a better quality video. We use pretty much the same technology as youtube I think, and I'm also pretty sure the quality trialstube encodes to is higher than youtube. And yeah, please remember you can still download the full, uncompressed, origonal source file from TrialsTube!