I don't get it, VOOM says it uses MPEG-2 and MPEG-4. How the hell do you get HDTV using MPEG-4?
They are re-encoding and recompressing their HDTV feeds (stat mux). They would simply re-encode and recompress in real-time using MPEG-4 instead of MPEG-2.
Based on posts by their vp of engineering, they plan to use MPEG-4 for SD in 2004, and MPEG-4 for some HD in 2005. MPEG-4 doesn't offer much benefit over MPEG-2 for 1080i, but it should help some for 720p.
The MPEG-4 support will come in the form of a plug-in module (not unlike the 6000) that will be shipped to all customers at some point next year. It might also be possible for them to upgrade their receivers to support H.264 or WM9 at some point, but that's yet to be determined.