First off, please allow me to rant about CRAPTASTIC SERVICE from comcast
I dont know about your area but Comcast here is like AMMOMAN - its great untill you run into your first problem, then its all downhill from there. The comcast# has liars working that will tell you anything on he phone (plain out LIE) to you so be ready....
I just moved into a new house and when first placing my order for comcast:
Internet
Basic cable
HBO and skinamax
I was told my FIRST bill would be close to $140 then each monthly bill would be about $115
My first bill was over $150... no big deal
my monthly bill is on average $140
ok so my first problem with comcast was none of the features would work (DVR,On Demand) I placed a call for a new cable box. (already going through enough issues with comcast at my sisters to have her cancel them) I advised the lady I needed a new HD/DVR/Cable box. I gave her the model of the one I had and advised that it was the newest one and would like the same one in return (duel tuner - full HD) When I was almost done on the phone I had the lady REPEAT to me what she understood the problem to be.... now me KNOWING there would be an issue called back about 2 hours later and asked about my last call.. was told that someone would be out to bring my new cable box....
the day before the apt, I got a call from comcast confirming the apt, I again asked to confirm the guy would bring the cable box... "yes sir, cablebox"
as you can imagine the comcast guy came to the house asking me what the problem was and did not have a cable box on hand. He gave me the paperwork and the detail said "customer needs a cablecard to access on demand channels"
Things like that piss me off to the point that I dont even care anymore if that makes sense?
Ok, now to answer your question…
if you have the new comcast box (no coax out, full digital box) then follow
THIS link. Explains how to pull the DVR saved shows to a computer and convert them to burn. This guy put alot of time into writing the code to do it all for you, then its a matter of just using your regular software to burn (nero,shrink,etc...) The picture comes out the same as it was recorded (HD or SD) once burned to a DVD.
ETA/ like posted above my post "But I'd double-check those prices, because Digital Cable + HD + HD DVR costs a LOT more from Comcast here"
yes, please double check because they are known for exactly this