Capture settings calibration - colour saturation

[FlimsyFeet]

Capturing from a BT878 card using the btwincap drivers and huffyuv compression.

I'm using Trevlac's colortools plugin for VDub and looking at the AVI file. Using the WFM and the luma, I've adjusted the brightness and contrast in the driver setting so that now whne I capture there is a good range of luma but without loss of detail in "crushed" blacks or clipped whites. So far so good.

Now, using the vectorscope, I looked at the colour saturation, particularly anthing bright red. I reduce the saturation in the driver settings so now when I capture the reddest pixels just fall within the "R" box on the vectorscope. However, the video has a sort of "de-saturated" feel to it. If I increase the overall saturation, the red bits go beyond the box and become "hot pixels".

Should I look at adjusting any of the other settings, e.g hue, or white balance, to reduce this part of the chroma?

Or is it something I should look at fixing with post-processing. Can you use the ColorYUV command in AviSynth to do anything with this?

[hartford]

I reduce the saturation in the driver settings so now when I capture the reddest pixels just fall within the "R" box on the vectorscope. However, the video has a sort of "de-saturated" feel to it. If I increase the overall saturation, the red bits go beyond the box and become "hot pixels".



No knocks by me.

Should be a "hot" subject.

I think that ColorMatrix.dll was introduced to fix this problem.

I'm probably wrong because I don't understand, or you haven't made clear to us what you are trying to do.

[trevlac]

Should I look at adjusting any of the other settings, e.g hue, or white balance, to reduce this part of the chroma?

Or is it something I should look at fixing with post-processing. Can you use the ColorYUV command in AviSynth to do anything with this?
Hi

Is your source really out of wack when viewed on a TV? If not, I would error on the side of fewer changes. Adjust things so you don't loose part of the signal (clipped on top or bottom) ... but be careful about adjusting color too much by eye on a PC monitor when your final output is a TV. Hue should be ok unless you are talking about camera source lighting issues or some restoration stuff. But then you'd probably want to make changes on each scene/clip in post.

The boxes on the scope are for a 75% saturation signal. Normal color bars should fall in the boxes. But a signal could contain higher levels. Not all colors are 'hot' past 75%. Hot is really a broadcast composite issue ... but not a bad guide on what will glow on a TV.

You can also use the waveform monitor to see if the red is crushed at the top.

BTW:
I'm just as much of a novice as many here :D I just don't know enough to give an outstanding clear guide. The scopes help me get an idea of what I am doing to the image. But I still look at the image.

I find Tweak() [by D.Graft] to be the easiest AVS filter for changing color. Tweak(sat=1.1) increases saturation. I made a version that let me go after specific hues and saturation levels without effecting everything.

http://forum.doom9.org/showthread.php?t=88727&highlight=tweakcolor

[FlimsyFeet]

Is your source really out of wack when viewed on a TV?Not really out, but some things that are bright yellow or bright green in the source appear almost white in the capture.
The boxes on the scope are for a 75% saturation signal. Normal color bars should fall in the boxes. But a signal could contain higher levels. Not all colors are 'hot' past 75%.It seems to be only the red pixels that extend into the box.

You can also use the waveform monitor to see if the red is crushed at the top.Not sure if I'm doing it correctly, but all colours seem to clip at the top? Especally for white lights. But the luma doesn't really clip. How can that be, I thought the luma was a combination of r, g & b?

I'm just as much of a novice as many here :D
You're too modest!