things that you record on the TIVO is transferable to the PC, however its in its own fancy(and shitty) wrapper beacuse well, weak hardware compressing 720p on the fly

I do not have experience on the com cast DVR, if you have an HDMI port on you computer you could screen cap non protected stuff (DAMN i knew the word i wanted there when I started this post) However the big key for that is out so I think by this time there are apps that are distributed for free that would break that, obviously so you can use your media for the full extent the law allows and not a step over *cough cough *