The Tivo calculates about 3 GB / Hour in best quality for video data. I noticed that in reality it is closer to 2-2.5 GB / Hour (using Tytools, I saw the capacity per program) for many programs.
On the other hand when I grab analog video using a capture card on my PC, I get about 3.5-4 GB/Hour (Mpeg II).
The video quality on the TiVo seems excellent, and the question is how come the difference. Is there a way to get similar results on my PC using Mpeg II ?
This goes true to professional DVDs as well. Although most forums on the net claim that professional DVDs can pack 2 hours of video onto a DVD because they use a 2 layer media, the fact is that many high quality DVDs still fit in the 4.4 GB restriction of a regular DVD. Can someone explain this to me as well?

In a followup (naive ) question, is there a way to transfer the Tivo video files to a PC by copying directly from the hard drive (connecting it to the IDE bus of the PC) ? Would I be able to use the Tytools then to convert to mpegII?

Thanks,

Gideon.