These sliders implement the color correction to enhance your video without
sacrificing of the processing speed.
That's because the parameters are embedded into the matrix for YUV->RGB
transformation, so it does not matter for the speed whether you ask for color correction
or not.
This is adjusted by shifting the values of all three
(intensity and two color) channels equally
after the contrast settings were applied.
Setting +50 means
shifting the middle level (127) to the maximum (255).
Setting -50 means
shifting the middle level (127) to the minimum (0).
This slider stretches (or shrinks) the ranges
of all three channels equally.
Setting +50 will
double the range of values, and
setting -50 will halve it.
This stretches (or shrinks) the ranges of the two color channels equally.
This stretches the range of one color
channel while proportionally shrinking the range of another.
With this feature, you can correct the effects of distorted colors
in your video source, such as "yellowish film" or "pink faces".
These sliders adjust the color tint by shifting the values
of the corresponding color channel.
The color map represents the color tint that you can
obtain by combining the two sliders.
For example, to reduce the yellow tint in the source video,
you need to shift from the Yellow area to
the Neutral (at the center). That is, you have to set
Shift Red to negative and
Shift Blue to positive.
Note, that unlike the Saturation Balance these sliders will shift the whole range of color values, so make sure that the dark areas in your video remain colored properly.
This information helps finding the optimal color correction settings.
The numbers in frames are the relative amount of pixels that get their
levels (Intensity, Color-U, or Color-V) exceeded the range of 0...255 due to
the color correction (the parameters listed above).
The exceeding values were clipped in order to fit into that range
(8 bit per color channel, i.e. 24-bit or True Color).
It is recommended at first to locate a frame in Preview window with most vivid colors and then adjust Brightness and Contrast so that the Intensity percentage becomes about 0.1% for both high and low levels.
The percentage for the color channels can be a little bit higher, which is controlled by the two Saturation sliders and the two Color shift sliders.
This button will open an additional window where you can
watch the effect of your color adjustments.
The time lag is present only when changing frames, but
once the frame is selected, the effect of changing the
color parameters is displayed right away.
The Preview button is disabled if no video file was opened in VirtualDub.
This checkbox allows turning off the color correction in
order to compare the corrected and the original images.
If checked this will bypass all current setting for color correction.
Can be used only with Preview.