I used kmttg to extract episode of the Winter Olympics from my TiVo to my Mac. After the default transfer, decryption, and transcoding (all default settings) I'm left with a 7 hour, 30 GB MPG file.
I can't think of a way to strip the audio out right off the top of my head and still keep it as an mpeg. snipboy: your question is a little bit different. For you you can open an mpeg with ...