LUTDeCrawl

Abstract
Author	Scintilla
Version	10/3/08
Download	LUTDeCrawl
Category	Rainbow & Dot Crawl Removal
Requirements	YV12
License
Discussion

Description

LUTDeCrawl, a dot crawl removal script by Scintilla.

Requirements:

- AviSynth 2.5.8 or later

- Supported color formats: YV12

Required Filters:

• MaskTools2 2.0a48+

Syntax and Parameters

LUTDeCrawl(clip input, int "ythresh", int "cthresh", int "maxdiff", int "scnchg", bool "usemaxdiff", bool "mask")

ythresh int = 10

This determines how close the luma values of the pixel in the previous and next frames have to be for the pixel to be hit.

Higher values (within reason) should catch more dot crawl, but may introduce unwanted artifacts. Probably shouldn't be set above 20 or so.

cthresh int = 10

This determines how close the chroma values of the pixel in the previous and next frames have to be for the pixel to be hit. Just as with ythresh.

maxdiff int = 50

This is the maximum difference allowed between the luma values of the pixel in the CURRENT frame and in each of its neighbour frames (so, the upper limit to what fluctuations are considered dot crawl).

Lower values will reduce artifacts but may cause the filter to miss some dot crawl. Obviously, this should never be lower than ythresh. Meaningless if usemaxdiff = false.

scnchg int = 25

Scene change detection threshold. Any frame with total luma difference between it and the previous/next frame greater than this value will not be processed.

usemaxdiff bool = true

Whether or not to reject luma fluctuations higher than maxdiff.

Setting this to false is not recommended, as it may introduce artifacts; but on the other hand, it produces a 30% speed boost. Test on your particular source.

mask bool = false

When set true, the function will return the mask instead of the image.

Use to find the best values of cthresh, ythresh, and maxdiff. (The scene change threshold, scnchg, is not reflected in the mask.

Examples

AviSource("Blah.avi")
LUTDeCrawl()

Changelog

  10/3/08:
     - Is this thing on?