I've been exporting HD videos from iMovie '09 directly to YouTube using the 720P option from the Share -> YouTube menu. However, it seems I get a vague error message when I upload a video that approaches 5 minutes in length. 1) Can anyone confirm a video length limit for HD videos on YouTube? I know for SD it is 10 minutes but could not find a separate limit for HD video. 2) I understand YouTube limits uploads to 100MB but my video files are several GB before iMovie converts them to "YouTube HD" format. The problem I'm running into is I don't know when I approach the 100MB limit since the formatting is all done automatically through iMovie/YouTube. Is there a way to figure out the file size of my YouTube HD movie before iMovie tries for half an hour to upload it and get rejected?