High-Def on a PC

Richard Baguley

Richard Baguley is a freelance writer based in San Francisco. He watches a lot of TV.

There are many reasons why you might want to record a TV program on your PC. You might be building a media server that stores all of your digital audio and video, or maybe you just want to save a favorite program to DVD to watch it later. Whatever the reason, you have a right to record and keep the TV you watch, and the PC is a perfect tool to do this.

Such recording becomes even more compelling when you add digital TV to the mix. TV stations are moving over to a digital format, where shows are transmitted digitally at high-definition resolutions. Forget snowy, grainy, analog TV: Digital TV provides crisp pictures and clear, digital sound.

Off-the-shelf devices such as TiVo and Replay TV are known as digital video recorders because they record analog video in a digital format, but they don't capture and record digital TV signals. (If you're a satellite customer, DirecTV offers an HD DVR based on TiVo technology, but the company also recently announced it would no longer sell TiVo equipment).

For now, if you want DVR-style control over HD, you might want to build a system yourself. Several PC tuner cards can receive a digital TV signal and save it to disc--the ATI HDTV Wonder and the PCTV HD-3000, for example.

If you're interested in creating a DVR that can handle HDTV signals, here are some questions you might ask.

Q: Will I need to upgrade my PC? A: A fairly recent system, with at least a 2-GHz Pentium 4 or Athlon 2800+ processor or higher, at least 512MB of RAM, and an 80GB or bigger hard drive will probably be fine. For our step-by-step guide, we used a 2.6-GHz Pentium 4 system with 1GB of DDR333 RAM, but an even faster processor would have made some things (such as converting the recorded files to different resolutions) quicker and easier. ATI recommends at least a 1.2-GHz processor and 256MB of memory for its HDTV Wonder card, but frankly, that's a bit low.

Q: Do I need a special antenna to receive digital TV signals? A: No, but you might need to get a better one. Digital TV signals are in the same frequency band as the existing signals, so (despite what the nice salesman at the store told you) you don't have to buy a new one. You might want to think about it, however: Digital TV signals tend to require a better antenna than analog signals. If you live close to a transmitter, you may not need more than a small antenna that sits on top of the TV. The FCC has a Web site that, when you enter your address or zip code, will show you which local stations are transmitting in digital format. Another site can tell you what type of antenna you might need to pick them up.

Q: Can I use these PC tuners to record HD programming from satellite or cable TV? A: Generally speaking, no. Satellite TV companies transmit their channels in a digital format, but they use their own methods of encrypting the signal, and we aren't aware of any PC tuner that can decrypt and record these signals. Also, most HD satellite tuners have either a DVI or a component video output, and we don't know of any consumer-level cards that can capture and record such signals. Some cards can work with a digital cable TV standard called QAM, but most cable companies either don't use it or encrypt such signals, forcing you to use the set-top decoder box that you rent from them.

Q: What kind of software will I need to build an HD DVR? A: I chose to use KnoppMyth, a combination of Knoppix Linux and the Linux software MythTV. It's the simplest way I've found to build a dedicated digital DVR, and MythTV has a huge range of features: It can search for programs by title, actor, or description; read RSS news and weather feeds; show your digital photos; and play Internet radio stations. Plus, KnoppMyth installs from a single CD, so you don't need to know Linux to install and run it.

Q: I'm not sure I'm ready to build a dedicated Linux box to record digital TV. Is there a Windows alternative? A: Yes. ATI includes software with its HDTV Wonder card that can view and record digital TV signals, including HDTV ones. You can schedule recordings and pause live TV; the card also includes an analog TV tuner. It is able to record digital TV signals with relative ease, although it requires a fairly fast PC to be able to record and play back HD video. Another alternative is the AccessDTV Digital Media Receiver, a PCI card that includes software that can record and display digital TV in Windows.

If you've read all this and feel ready to turn your PC into a HD-hungry DVR, I can take you through the steps. Check out PCWorld.com to learn how I built a DVR that could receive digital signals.