Color Matrix
 

Hi all,

The whole time I've owned my XH A1, I could tell that the colors where wrong, and I think I have finally figured out why. Even though the color bars generated by the camera are Rec-709, when actually filming the color matrix (CMX) setting appears to output Rec-601 YUV when set to Normal (default) and only properly outputs Rec-709 YUV if you change it to Cine1.

Does anyone know if this is correct? The manual is useless. In my testing I filmed in both Normal and Cine1 and then applied a filter that converts between 601 and 709, and lo and behold it exactly converts between the two.

Cheers,
Anna

P.S. Note that may editing applications like Premiere incorrectly interpret HDV footage as 601 anyway, so some people would not notice the problem.

How about this: Does anybody know what color matrix does?

Thanks,
Anna

from Canon's site:

"Color matrix: This adjusts the color during shooting. The available settings are NORMAL,
CINE1 and CINE2. The NORMAL setting is a matrix based on the assumption that images will
be viewed on a TV monitor. If CINE1 is selected, the resulting quality and grayscale
resemble those of a movie film. This is a matrix for creating images on TV that appear like
movies. The CINE2 setting is a matrix that is for images being transferred to film for viewing."

Anna and Bill Thanks for sharing.

Could someone explain 601 and 709? (School's in session)

Yeah, I've seen this. Its very vague. I would love to know what color matrix ACTUALLY does. What's the specification? The "TV Monitor" reference strong suggests Rec-601, since that was to standard for analog TV. But is that it? Is it more than that? Or something else entirely?

Cheers,
Anna

They are two different TV standards. 601 is for old analog TV. 709 is for HDTV.

One way they differ is the conversion between RGB and YUV. Decoding YUV footage with the wrong matrix, i.e. using 709 when the footage is 601, or visa versa will mess up the colors in weird, quite noticeable ways. For example, giving people's skin a strange yellow-y look. Important to know, wrong decoding effectively remixes all the channels with each other in a general linear combination, and it can not be fixed with color correction tools. So its very important to know whether a camera is recording 601 or 709. Unfortunately, camera manufactures generally won't just out and say it in the manuals, leaving you to try to visually spot it. Or record color bars and decode them both ways to see which is right. All SD cameras are 601 as far as I know. HD cameras are supposed to be 709, but they sometimes are not. And it seems possible that the XH A1 even goes so far as to generate 709 color bars, but 601 footage by default :(

Rec. 601 - Wikipedia, the free encyclopedia
Rec. 709 - Wikipedia, the free encyclopedia
YUV - Wikipedia, the free encyclopedia

Cheers,
Anna

Color Standards
 

What do you suppose happens when converting from HDV to SD?

Thank you, Anna.