Originally Posted by
directhex
sky does not give you digital. this is ANOTHER source of confusion.
it's probably easiest to explain on a per-source basis
source 1: analog terrestrial tv
to receive this, you need an analog framegrabber card (which relies on your CPU to do all the work), or an analog encoder card (such as the the pvr150, which has its own cpu to encode things to a useful format)
source 2: sky or ntl
sky is digital satellite, but you cannot (legally) receive sky without using a sky box. once it's in the sky box, the only way to get it out again is via analog capture - the same types of card as above (usually using the s-video connector on one of said cards). you combine one of the cards with an "ir blaster", which emulates a tv remote (so your software on your pc can send a signal for "101" when you try to switch to bbc1, for example)
source 3: freesat (not from sky) or freeview
for these, you need an appropriate digital tuner - be it a DVB-T card for terrestrial or DVB-S for satellite, with a possible need for DVB-S2 in the future. mpeg2 (or h264 for hd) streams fly around the sky, and are simply grabbed by your tuner and saved to disk. features such as an EPG are entirely dependent on your software (digital TV can carry guide data and interactive data, but not all software can use them)