TComb

Abstract
Author	tritical
Version	v2.0 Beta 2
Download	TComb
Category	Rainbow & Dot Crawl Removal
Requirements	YUY2 YV12
License	GPL
Discussion

Description

TComb is a temporal comb filter (it reduces cross-luminance (rainbowing) and cross-chrominance (dot crawl) artifacts in static areas of the picture).

It will ONLY work with NTSC material, and WILL NOT work with telecined material where the rainbowing/dotcrawl was introduced prior to the telecine process!

It must be used before ivtc or deinterlace in order to work. In terms of what it does it is similar to guavacomb/dedot.

TComb does support seeking... that is, jumping to a random frame will produce the same result as if you had linearly run up to that frame.

For dot crawl removal tcomb requires at least 3 static fields of the same parity and for rainbow removal tcomb requires at least 5 static fields of the same parity.

Requirements:

- AviSynth 2.5.8 or later

- Supported color formats: YUY2, YV12

Syntax and Parameters

TComb(int "mode", int "fthreshL", int "fthreshC", int "othreshL", int "othreshC", bool "map", float "scthresh", bool "debug", int "opt")

mode int = 2

Controls whether both luma/chroma are processed or only one or the other. Possible settings:

• 0 - process luma only (dot crawl removal)
• 1 - process chroma only (rainbow removal)
• 2 - process both

- default: 2 (int).

fthreshL int = 4

fthreshC int = 5

Filtered pixel correlation thresholds.

One of the things TComb checks for is correlation between filtered values over the length of the filtering window.

If all values differ by less than fthreshL (for luma) or fthreshC (for chroma) then the filtered values are considered to be correlated.

Larger values will allow more filtering (will be more effective at removing rainbowing/dot crawl), but will also create more artifacts.

Smaller values will produce less artifacts, but will be less effective in removing rainbowing/dot crawl. A good range of values is between 4 and 7.

- default: fthreshL -> 4 (int)

fthreshC -> 5

othreshL int = 5

othreshC int = 6

Original pixel correlation thresholds.

One of the things TComb checks for is correlation between original pixel values from every other field of the same parity.

Due to the oscillation period, these values should be equal or very similar in static areas containing dot crawl or rainbowing.

If the pixel values differ by less than othreshL (for luma) or othreshC (for chroma) then the pixels are considered to be correlated.

Larger values will allow more filtering (will be more effective at removing rainbowing/dotcrawl), but will also create more artifacts.

Smaller values will produce less artifacts, but will be less effective in removing rainbowing/dotcrawl.

A good range of values is between 4 and 8.

- default: othreshL -> 5 (int)

othreshC -> 6

map bool = false

Identifies pixels that are being replaced with filtered values.

Each pixel in the output frame will have one of the following values indicating how it is being filtered:

            0 - not being filtered
           85 - [1 2 1] average of (n,n+1,n+2)
          170 - [1 2 1] average of (n-2,n-1,n)
          255 - [1 2 1] average of (n-1,n,n+1)

           ** n = current frame

Examples

AviSource("Blah.avi")
checkmate()

Changelog

 :
     - Initial release