RadiaLum Filter for Virtual Dub - Version 2.0

 

(c) Alessandro Malanca - Jun / 2002

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

 

[Place this text file in the VirtualDub plugins directory]

 

Performs a radial intra-frame luminance correction. It has been developed to correct luminance for films shoot from 8 mm and Super 8 sources. Such a films normally have the centre of the frame that is brighter than the border. The filter uses a tstudent function to correct the luminance. It allows adjusting luminance and rgb colours too. I suggest you to use it also if you need just a brightness, contrast, colours correction filter. I think it allows for better corrections than standard filters. It can go faster than a standard correction filter because of the algorithm I use: it builds, according to user selected parameters, 3 pixel remapping vectors, so no calculus at all are performed while processing frames (except for radial correction). Controls are not as much sensitive, but I think the best correction is no corrections at all; if you need more correction just ask.

 

Parameters description:

 

Radial correction:

Defines the amount of radial luminance correction applied.  Leftmost (0) means no correction at all. Rightmost means (100) maximum correction.

 

Radius:

Allows to change the radius of the correction, moving left you concentrate the dark correction to the centre, moving right you spread the correction to the borders.

 

Interlaced:

Check it if the source frames are interlaced.

 

Title disable threshold:

This is a trick I use to disable the radial correction on solid titles. If it is less than 255 it looks for the top-leftmost and top- rightmost five dots of each frame. If the average luminance of these ten dots is above the given threshold, the radial filtering is disabled. (I use to force some white dot, in the top corners of the titles).

 

Brightness:

Globally correct the luminance.

 

Contrast:

Corrects the frame contrast.

 

Green-Red:

Adjust colours from green to red.

 

Yellow-Blue:

Adjust colours from yellow to blue.

 

Disable Filtering:

While in preview mode, this button allows to enable/disable the filter applied to check differences.

 

Sample frame:

     Forces to sample the current preview frame in the shown histogram.