Accellent is a "proof of concept" allowing you to watch HD video on non-officially supported hardware. It is based on a reverse engineering of the IDCT hardware acceleration APIs found in Mac OS X.
If the application is still a beta version (Release v0.3.1), a reader from
Xlr8yourmac has successfully played a MPEG 2 video in 1080p format on a G4 1.33GHz-based Mac, without saturating the CPU. This software can currently only decode the video signal, but the main goal is to integrate it to another already existing application, named
iTele.
For sure Mac mini G4 could then be a perfect and cheap system for HDTV at home.
More information can be found hereafter:
http://www.defyne.org/dvb/accellent.html