Onboard encoding or not?

[NES_Master]

I sort of started a little argument with someone and I'd like to know if I'm correct or not. Basically someone posted asking what kind of capture card they should get. Someone responded,

doesn't really matter, just make sure it has philips tuners and not samsung (or generic for that matter)

Of course, I'm all for onboard encoders, so I express how poor the quality is should you try and capture. Well, uncompressed might work, but the file size would be so huge.

Anyway, what do you guys have to say. We're just talking about standard TV Tuners here, nothing using DV, any high end equipment like DV-REX/Storm, or anything else like that.

And here's the post if you'd like to read the whole thing...
http://www.computerforum.com/87005-best-tv-tuner-card.html

[jagabo]

A capture card that captures video as YUY2 (or similar) and transfers that to the computer where it is saved uncompressed or losslessly compressed (HuffYUV for example) can deliver better quality than a card that compresses to MPEG2 (or DV). But many other factors will come into play.

First there's the quality of the analog to digital conversion, what resolution it's actually performed at, how many bits it's handled with internally, how clean the analog circuitry is (free of noise), etc.

Then there's the transfer to the computer. It can be much harder to get a perfect capture with YUY2 captures. You may have to stop all background processes and refrain from touching the comptuer while it's capturing. Faster CPUs and faster hard drives are reducing the problem of dropped frames. Hardware MPEG encoders have it much easier. I find it almost impossible to get my PVR-250 to drop frames.

MPEG encoding on-the-fly, hardware or software, has a limited amount of time to perform it's work. The search for motion vectors will be limited resulting in less compression per frame, lower quality per bitrate. MPEG encoding also creates artifacts at pretty much any bitrate, especially with noisy sources. Look at some enlarged still frames from your PVR-150 caps -- you'll see macroblocks even from a clean source. You may also see DCT ringing artifacts at very sharp edges. If you capture at DVD compatible settings and burn directly (or with simple cut/paste editing) the quality won't be too bad. But if you need to perform a lot of filtering YUY2 will get you better results.

[NES_Master]

That's pretty much what I was trying to say... I know uncompressed video is better, but it's very impractical unless you have massive amounts of hard drive space. Then when encoding real time(software) most computers can't keep up. I recall my old Athlon 4000 couldn't really do anything above VCD quality or so...

I'm sure my WinTV leaves some artifacts and all, but as long as the video's rather clean, they are really not noticable. I've done my share of converting old VHS tapes to DVD and never has the quality appeared worse than the original. At least at a glance...

[jagabo]

Most modern computers should be able to handle YUY2 with Huffman compression. It will depend on the capture card and drivers to some extent.