Colors Adjust filter for Virtual Dub    

(c) Alessandro Malanca - April / 2006

http://web.tiscali.it/minomala/index.htm 

[Place this text file in the VirtualDub plugins directory]

This filter allows you to adjust colors in RGB space using an approach similar to the one used in YUV space.  Pratically for each  RGB= (R,G,B) pixel, Luma is assumed (more or less) as Luma= MIN(R,MIN(G,B)) and chromatic components as : Red= (R-Luma), Green=(G-Luma), Blue= (B-Luma). Here on the usal corrections  gain, offset and gamma are applyed to the 4 channels (Luma,R,G,B). Moreover the additional 3 dimensional channel GLOBAL (Red,Green,Blue) allows you to adjust the global color saturation

Controls description:

Select Chan.:

This button selects the current channel: luma - global - Red - Green - Blue. Corrections are applied to the selected channel.

Offset sliders:

Corrects the brightness globally and for red, green or blue colour.

Gamma sliders:

Corrects the gamma (mid tones luminance) globally and for red, green or blue colour.

Gain sliders:

Corrects the contrast globally and for red, green or blue colour.

Balance media: This value is the reference point for brightness control. Values above are incremented, and below are decremented. You can also set it to 0 to have the usual contrast control.

Colors histogram:

In preview mode, shows the distribution of pixel values from 0 to 255; globally and for red, green or blue.

Max: is the amount of points indicated by the histogram max value.