16-Bit vs 32-Bit: Any difference when capturing?

[Jeomite]

I noticed if I leave my resolution at 16-bit it takes only ~40% CPU Usage during captures. While if I leave it at 32-bit, it holds a steady ~95-100% Usage.

My question is does it matter what bit I use for my captures? Does changing the color depth affect my captures in VirtualDub?

Thanks for any input.

[Merry Christmas too! =]

[Jeomite]

*Bump*

Anyone know? =|

[buzz10]

Definitely you should keep your color set at 16-bit High color. Of course it stands to reason that a higher bit-setting is going to require more processing power from your CPU, and you don't want to be wasting any of that precious CPU on anything but your video capture. So, yes, leave it at 16-bit. Besides, your eye will not be able to distinguish between 16 bit and 32 bit color anyway.

[kinneera]

Actually, that processing power will come from your GPU, not your CPU, but of course that's even worse.

[vitualis]

Don't know the answer to this question... but in some circumstances, you can definitely tell the difference between 16-bit and 24/32-bit colour...

Regards.

[Jeomite]

Thank you for the replies. =]

I'll stick to 16-bit. Not sure if it's related, but previously when I left it at 32-bit, my computer would lock up after a few minutes in capturing. It have not locked up once since I left it at 16-bit color depth. =]

[tacosalad]

You didn't mention which 16-bit mode you're using.

Just be careful not to use 16-bit RGB if you can avoid it. While the 16-bit YUV modes like YUY2 and UVYV has 256 shades of pure gray, an RGB16 capture has only 32.

RGB16 and RGB15 are quite damaging to a video capture from NTSC or PAL. Most cards provide these modes for VGA compatibility, and some use dithering to hide the loss of dynamic range. That's okay for previewing on the screen, but it won't compress so well into MPEG, Indeo, or DivX.

If your card uses a Bt878 capture chip, it doesn't capture RGB24 or RGB32 natively; it captures 16-bit YUV and then converts that to RGB. Hence, a 16-bit YUV capture (like YUY2) should be as good as a 24-bit RGB capture, all other factors being the same.

"Should" is the key word here, though. Results do vary, so be sure run a comparison with your setup.

-tacosalad