I've been using Premiere Pro for more than a year, and I love it. However, I am increasingly ouputting HD files for upload to YouTube and I am experiencing problems with nearly every file. The files, generally created using H.264, play perfectly on my PC (a reasonably high spec VAIO bought specifically for video editing), but when I upload to YouTube I experience pixellation or even complete jumbling of sequences on one extreme occasion. I've tried many different presets, but this problem keeps happening. I don't know whether the problem is local (maybe I'm using the wrong presets or perhaps my PC is struggling with rendering large HD files - but then why do they play perfectly on my PC?) or whether this is a YouTube problem. Has anybody got any views or experience that could help here? I'm going nuts.