[Mplayer-dvb] fast transcoding?

[Christoph Gohle]

Hi,
I'm very interested in the feature called "realtime transcoding between 
MPEG2 and MPEG4 (partial decompression)" in the mplayer manual since my 
vdr-box is by far too slow to do this job and I don't want to buy new 
hardware, if my DVB-Card could already do half the work...

How similar are the two formats really? Does anyone have a nice 
documentation on the mpeg-fileformats. If I had a nice documentation, I 
would even try to implement this feature myself.

Greetings,
Christoph