I’m not sure what you mean by “building your own TiVo”.
I’ve built several HTPCs (Home Theater PCs) that can act as DVRs (digital Video recorder - think “digital VCR”). That’s a fairly trivial. I thnk my simplest was a $20-30 BT787 chipset video capture card on a Celeron 466 under Win98.
It’s sitting across from me in my bedroom right now, and though it’s a bit underpowered and sometimes drops frames when my cable gets almost a bit staticky (which doesn’t happen often). it’s quite decent [at LEAST as good as VHS for playback clarity to my eyes, though I usually recorded at 360x240 30 fps, rather than 640]. Generally recommend a 800Mhz P3 or better if you aren’t interested in tweaking your settings to get glitch-free recording. Though I’ve long been an Athlon fan, I recommend using an Intel CPU/chipset because they handle AV hibernation much better than most Athlon mobos.
I recommend the BT787 (or other BT7x7) chipset. These are, by far, the most common chipsets for standard video capture. There’s lots of support for them on boards like the AVSforum [everything you wanted to know about AV - and a whole lot you didn’t. Check out the HTPC forum there] I don’t recommend the ATI solution. Though I haven’t checked them out recently, they have such a long history of inefficient proprietary drivers that it’d take several years of stellar performance to make me consider them. I’ve had lots of ATI cards, but I wouldn’t use them for video capture
I suggest trying the free “tweaked” generic BT787 drivers from IUlabs.com (or similar) It’s amazing how much the quality of the OEM drivers vary. You’d think that they’d get the bugs out, considering how long the 7x7 has been out, and how well many of the major amateur-written drivers work.
You can use the program that ships with it, or any of the popular independent free or commercial Digital VCR programs. It’s a matter of personal taste. Do your homework on that choice. The user interface, remote control, and software features are the most important elements for casual users.
I’ve heard very good things about the open souce/linux solutions listed above for NTSC (normal video). There are others on Sourceforge.org as well. I just haven’t played with or updated my HTPCs in ages. They’ve become no-think video appliances (and isn’t that what we really want?)
If you are interested in HDTV, there are several good cards in the $250 range - cheaper than any standalone HDTV tuner I’ve seen. I personally have a MyHD card from MIT, and though its proprietary software is a little quirky, I’ve never had any real usability issues with it. If I had to do it all over again, I’d research the other options though. My choice was the right one for me at the time (late 2002) because the other HDTV cards were more expensive, and I just wanted to “get my feet wet” in HDTV. At the time, I think it was the only card that had two video inputs, so I could hook up and program my cable and my rooftop antenna (for HDTV broadcasts) separately, There may have been another but it was almost twice as expensive.
My myHD now lives on a 2+ GHZ Intel (which I picked up for well under $200 on eBay from a once prominent PC merchant who alas no longer eBays). It also ran happily on an Athlon 1700+ XP (whose real clock was more like 1.3 GHz) and briefly on a sub GHz P3. Each system plus the MyHD cost less than many HDTV tuners alone when I built them.
Aroint Thee hence to the HTPC forum of the AVS Forum It has all the answers. The AVS forum also has boards for every aspect of the project, like remote controls, compact cases, audio, etc.