said by andyross:
The Motorola DCX series, and I'd assume any box released within the past year or two, supports MPEG4 natively in hardware. It may be possible to add MPEG4 to older boxes, but it might require running in software, which may be too much for most. Maybe a non-DVR DCH could do it, but the extra overhead of DVR or older models would probably choke it.
Yes as I mentioned a few posts back in this thread, anything Comcast calls an "RNG" decodes MPEG4 (this includes the Moto DCX series). And the new (not being used by Comcast just yet) HD DTAs do too.
»Re: [HD] FIOS Moving to MPEG-4 HD
And no, there is no way to add it the older boxes, the boxes have very limited CPU resources as-is, they rely on dedicated video decoding silicon. So they're stuck the way they are.
That's why Comcast made the "RNG" specifications to tell their cable box vendors (Cisco, Motorola and Pace) what minimum specs for future proofing must be. All the boxes that are labeled RNG by Comcast will eventually get the X1 Guide software ported over to them.