Videographica: TV Tuners

People wanting to get into the PC video capture world on the cheap often find themselves attracted by TV tuner cards. And why not? A basic model is only 30-60 bucks. These cheap cards aren't without their troubles, however. Here are a few things I've discovered over the years.

They Never Come Tuned Right

I have yet to put a capture card in my PC that comes with the color controls set properly, no matter how expensive it is. TV tuner cards seem to be the worst of the lot: they're usually farther off than more expensive cards, and their color controls are often overly sensitive, making it difficult to tune the colors correctly. Worse, most people don't know enough to tune their video systems properly. The four color controls — contrast, brightness, color, and tint — are usually interactive: if you set one properly, then change another, you'll most likely have to go back and change the first one again.

The best way to do this is to get a video calibration DVD. Most recently, I've been using the AVIA Guide to Home Theatre DVD. Why should you spend $40 on a disc to calibrate a capture card when you probably didn't pay much more than $40 for the capture card? Given that the card will be poorly calibrated out of the box, if you can't fix the picture, you won't get the full value out of your purchase. Plus, you can use the calibration disc to tune your television(s) as well — trust me, your TV is probably capable of a much better picture, if only it was calibrated. (For what it's worth, I also used to use the Video Essentials DVD, but AVIA completely outclasses it, and it's a touch cheaper besides.)

Keep in mind, calibration won't save a badly-designed card. I had an old AITech WaveWatcher-pci laying about and decided to play with it a bit for this test. I tuned the thing with the test patterns on my tuning DVD, but when viewing normal video, the picture was overly contrasty and oversaturated. When I fiddled with the color controls to match the picture to my TV, I got good, watchable video, but then when I tried to save some shots to disk, the color was shifted again. It seems I couldn't simultaneously get watchable live video and watchable capture files.

They're Getting Better

There's no question, current TV tuners suck less than older ones. Here's a pair of screen grab details, the first from the older WinTV design based on the Brooktree Bt848 chip, and the second based on the newer Brooktree/Connexant Bt878:

Aside from stipply video like you see in the frame grabs, older designs tend to have smaller frame sizes, fuzzier pictures, and worse software. If you find an offer for a real cheap older card, I think you should avoid it unless you're just playing around with spare cash. If the store won't let you return it and you can't afford to buy something better if you're unhappy with it, you shouldn't buy it.

Does It Have the Frame Size You Want?

Older TV tuners were limited to the 320x240 frame size. (I use NTSC frame sizes in this section. If you're from a country that uses PAL or SECAM, the frame sizes used by capture cards for your country will be a little different.)

Modern TV tuner cards have at least a 640x480 frame size, but there are a few that have 720x480, which is the actual resolution of the TV signal. Beware: your card's software might offer you a 720x480 mode, but it may well simply be a 640x480 picture stretched out to 720x480. To know if your card truly supports 720x480, capture the same picture at both resolutions, then take the 640x480 version and use a good paint program to scale that image up to 720x480. If you can't tell the difference between the two, your card is probably scaling the picture. You want to use a highly-detailed still picture for this test, like a paused DVD.

Why is a 720x480 frame size desirable? For one thing, it's the standard DVD resolution. Now that DVD writers and DVD creation software are cheap, you shouldn't settle for smaller frame sizes.

How Good Is the Tuner?

In many cards, especially the older ones, the TV tuner section is worse than the same card's composite/S-Video capture section. Analog cable is full of video noise already and over-the-air television is worse, so you can't fault the TV tuners too much, but beware that you may well get a much better picture if you can avoid the coax cable input.

If you find yourself stuck with a card that has a rotten TV tuner but good composite or S-Video inputs, try using your VCR's tuner to convert cable or over-the-air TV to composite or S-Video. Even a cheap VCR might do a better job since it's not sitting in the RF interference bath you call a PC. :)

Cards I Like

Of the cards I've tried, I'm most happy with ATI's All-in-Wonders. They tend to be better specified than the market leader Hauppauge's WinTV boards: they do 720x480 frame sizes, I find ATI's software easier to use than Hauppauge's, and they come with a very good software MPEG encoder.

The ATI boards do have one problem which occasionally sends me running back to WinTV: the ATI boards replace your system's video card. This makes them more expensive than WinTV boards, and if you like your current video card you won't want to replace it just to get capture features.

Some of ATI's All-in-Wonder boards do come in PCI versions, so you don't necessarily have to replace your current video card. You can put them in your PC as a second video card, either just for capturing or to run a second monitor as well. Note that if you try to put two AIW boards in one machine, you do get dual-monitor support, but you can't use both boards' capture features. (I verified this with a PCI AIW 128 and an AGP AIW Radeon.)

If you need to do two captures at once, you can either put two WinTV boards in one machine, or you can put one WinTV and one AIW board in the machine. The latter configuration is problematic, though: you often get into situations where a capture program will only grab one board and not the other, so you have to do some trickery to force the program to grab the other board. Using a matched pair of WinTV boards works better.

Conclusion

Is a TV tuner the right thing for you? If you want to get into video capturing for a rock-bottom price, sure, they're great. Just be aware that you're getting rock-bottom features for that price.