Cnr2

Abstract
Author	Marc FD
Version	v2.6.1
Download	cnr2_v261.zip
Category	Temporal Denoisers
License	GPLv2
Discussion	Doom9 Thread

Description

This filter is a Chroma Stabilizer for analog sources. It's a temporal filter and it's very effective against two chroma artifacts: Stationary rainbows and huge analog chroma activity.
Cnr2 was inspired by the VirtualDub filter Chroma Noise Reduction 1.1 by Gilles Mouchard.

Requirements

• AviSynth 2.5.8 or later
• Progressive input only
• Supported color formats: YUY2, YV12

Syntax and Parameters

Cnr2 (clip, string "mode", float "scdthr", int "ln", int "lm", int "un", int "um", int "vn", int "vm", bool "log", bool "sceneChroma")

clip   =

Input clip.

string  mode = "oxx"

Mode of each components, "YUV":

• o : wide
• x : narrow; this mode is more sensible to variations, and less effective.
  

float  scdthr = 10.0

Scene change detection threshold (as percentage of maximum possible change):

If sceneChroma is set to true, then it is the maximum possible change including both luma and chroma.

If sceneChroma is set to false then it is the maximum possible change considering luma only (luma only is more reliable).

Lower it to make scene change detection more sensible. If a scene change is detected, Cnr2 will reset the filtering for the new scene.

int  ln = 35

int  lm = 192

int  un = 47

int  um = 255

int  vn = 47

int  vm = 255

l parameters control the luma channel, u and v corresponds to the U/V chroma channels respectively.

The n values are the movement sensibility; higher values will denoise more, but could produce ghosting artifacts.

The m values are the maximum effectiveness of the denoiser; lower them to reduce the denoising effect.

Range: 0 to 255

bool  log = false

Log the scene change stats (output them using OutputDebugString). You can use DebugView to see it.

It will simply list the detected change, the maximum allowable change for the current scdthr setting, and the ratio (at 1.0 or greater a scene change has occurred).

bool  sceneChroma = false

Sets whether or not both chroma and luma are considered on scene change detection (true), or only luma (false).

Luma only detection tends to be more reliable.

Examples

Cnr2 with default settings:

AviSource("Blah.avi")
Cnr2(mode="oxx", scdthr=10.0, n=35, lm=192, un=47, um=255, vn=47, vm=255, log=false, sceneChroma=false)

Changelog

Version     Date            Developer       Changes

v2.6.1      2004/06/30      tritical        - YUY2 opts as I had slowed it down
v2.6        2004/06/29      tritical        - Some bug fixes and some code cleanup and rewriting
v2.51       2003/11/18      Klaus Post      - Further bug fixes
v2.5        2003/11/13      Klaus Post      - Bug fixes
v2.4        2002/12/15      Marc FD         - Bug fixes
v2.3        2002/11/13      Marc FD         - YV12 mode, scd (scene change detection)
v2.2        2002/08/01      Marc FD         - Ugly bug fixed
v2.1        2002/07/31      Marc FD         - Bug Fixes (thanks to dividee ;)
v2.0        2002/07/20      Marc FD         - Initial release; AviSynth filter coded (from scratch)

Archived Downloads

Version	Download	Mirror
v2.6.1	cnr2_v261.zip	cnr2_v261.zip

Links

• Doom9 Forum - Cnr2 discussion.

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