View Full Version : S-video vs BnC--which is "true"


Josh Bass
October 22nd, 2007, 03:48 AM
Ok, so I'm attempting to color correct a short film in Vegas. I'm using a Sony PVM 14m2u connected via firewire preview, using the XL2 as a D/A converter. I have both a BnC out and an S-video out from the XL2 to the monitor. I just noticed that there is a slight difference between them in terms of contrast and color saturation. The S-video image is a little less contrasty/brighter and less saturated than the BnC image. So for color correcting purposes, which is "right"? The S-video would appear to be a higher quality image in terms of sharpness and no chroma crawl (which I get from using the BnC out on the XL2), so is it the S-video?

Furthermore, is there a quality difference between the BnC out on the XL2 and one found on a pro cam, say an SDX900 or something? If S-video is always higher quality than BnC, then why don't all the pro cams have S-video monitor outs instead of BnC?

Daniel Lippman
October 22nd, 2007, 07:30 AM
I can't answer your question about which has a better quality, or is true, for certain, but I can say that I am moderately certain it's S-Video. I was told that a BNC is essentially the same as component, but the reason it's favored so much is because it has locking connectors, which is a huge plus.

Greg Boston
October 22nd, 2007, 08:19 AM
In order of quality from low to high...

BNC (or RCA) - Carrying a composite signal.

S-Video - Separates the chroma and luma information

Component - Separates each color channel - sometimes has separate sync (5 connectors for R/G/B/H/V)

Keeping signals separated keeps them in their purest form because that's how they originate. If mixed to form a composite, they have to be separated again on the other side which degrades the signal a bit.

-gb-