A lot of movies are already stored in HD resolutions in MPEG2, and that includes Sony movies as much as other studios. It is therefore cheaper to release these movies in MPEG2 as there is little to no re-encoding needed. Converting these movies to another format would take time and money, and obviously the bulk of initial releases are all about releasing early to get some cash pronto, not about quality at all.
Don't ask me why this is happening with Bluray and not HDDVD cause that will be a mystery for a while, execpt for the fact that the initial Bluray movies were Sony's movies, and we all know why Sony wants to push MPEG2 more than other studios.
This makes sense. Digital TV movies are encoded in MPEG2 so releasing them cheaply in this format would make sense. I think that either the studios were waiting for MPEG2 on the dual layer 50GB BD disks (which have been delayed slightly) or they have all paid up for H.264 licenses and don't want to spend more licensing VC1. Of course with HD-DVD the capacity is lower, so you can't get decent HD with MPEG2, so they would have to license VC-1 or not release until H.264 gets going.
For some reason media companies seem very reluctant to go with VC1. Perhaps it has something to do with the mess in Windows Media formats, with Microsoft, Apple and Realmedia chopping and changing formats to lock each other out of their players. There seems little doubt that if VC1 is adopted, then Microsoft will create a new and improved VC2 which will only play on Windows PCs and media centers, thereby putting standalone media players at a competitive disadvantage compared to Microsoft's offerings. MPEG4/H.264 on the other hand is a committee standard which can't easily be changed or extended in a proprietary way to benefit one member.
I think pretty well all media companies will standardise on H.264 and not VC1. VC1 will be a Windows Media Format. In UK. Sky BSB, the dominant UK HD broadcaster was in discussion with Microsoft for two years about using the VC1 codec, but announced recently that it was dumping VC1 and going with H.264.
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