I don't think this is quality loss due to compression, because it's like this before I even compresses it; it's already pixelated on the virtualdub interface when I open it. Here are the specs of the video I'm using (via MediaInfo).
I have no idea why some MKVs convert fine and some come out horribly pixelated (and all of them play fine in Media player classic). I'm very noobish when it comes to these things though, so can anybody tell me why this is happening? The codec I'm using is K-Lite Mega pack, by the way. Needless to day, this is becoming really annoying. Thanks in advance! ^^