Okay it will depend on how new your Tivo box is? If it is a newer Tivo box that has dual tuner then you may be able to use it partially, remember that DirecTV only sends ALL of the channels in Digital signal, and cable channels (Even Digital cable channels) are NOT ALL digital. So Tivo upgraded theier newer models with dual tuners that can record 1 digital channel at a time, or 1 digital channel and 1 analog channel at the same time, or 2 analog channels at the same time. Now again with DirecTV you may be able to use 1 tuner only to capture the Digital signal.
If this does not sound great then there is another option. (DO NOT BUY A DIRECTV DVR, THEY ARE NOT TIVOS), you can find many DirecTV Tivo's on Ebay or garage sales or the like, just find one that is a Series 2 DirecTV Tivo and purchase it. It will work exactly as the Tivo brand except for networking and Tivo Desktop.
Now if you go this route then there is ways to upgrade the DirecTV Tivo's for networking, MultiRoom Viewing, Home Media Option, downloading the shows over you home network. Check out what I have written below and check out the sites. Hope this helps..
I have your answer.
First check out site #1 it has forums that explain how to hack your DirecTV Tivo and Tivo brand Tivo's so that you have Networking abilities on your D Tivo which allow MRV (multiroom Viewing if you have more than one D Tivo), HMO (Home media Option) which allows you to have a PC connected to your home network that can be used as a server for your MP3's and Pictures to be shown on your D Tivo. Once you hack the unit/s (HAS TO BE A SERIES 1 OR SERIES 2 DirecTV Tivo or Series 1 and Series 2 Tivo) you can apply some programs so that you can download the shows/movies from the decrypted programs stored on your D Tivo onto a PC for veiwing/Burning onto a DVD. If you have more questions I can give you alot more details if you email me. I have used these site below to aid me in Hacking 5 DirecTV Tivos (Qty2-SD-DVR40, HDVR2,Qty2- DSR704). I have HMO, MRV, can access over the internet with gotomydvr.com, can download shows/movies from all the units.
Site #2 is where you purchase the software necessary to upgrade the D Tivo, look for either their kits or if you want to upgrade yourself look at InstantCake 3.1 or 6.2, PTVnet, Slicer. (InstantCake is the operating system/ software displays you see on the screen, PTVnet is the software to boot the ISO disk you download onto your PC when you connect a NEW harddrive and it enables the USB ports and allows networking, The Slicer lets you get/receive upgrade from DirecTV without losing all your previous hacks upon software upgrades.)
#3 is a forum to get the other necessary software patches to allow you to decrypt the DirecTV signal before it is stored onto the D Tivos harddrive. And a patch to allow downloads of the shows/movies from the D Tivo. (Superpatch-67all-nutkase, and superpatch-62a, Tytool 10R4, and others)
#4 a forum on HOW TO and questions and answers
#5 a GREAT display of instruction with pics on how to remove the hard drive form the Tivo unit and install all the hacks)
#1 www.dvrplayground.com (Forum and instructions on how to hack units)
#2 www.dvrupgrade.com (site to purchase the DirecTV linux software to upgrade to a LARGE harddrive and enable the USB ports for networking)
#3 http://www.dealdatabase.com/forum/
#4 www.tivocommunity.com
#5 http://www.weethet.nl/english/tivo_dtv2_os6hack.php (for Version 6.2)
#6 http://www.weethet.nl/english/tivo_dtv2_os4hackrid.php (for Software Version other than 6.2)
Hope this helps, and have fun. Any other questions feel free to email me.