MosquitoNR

Revision as of 03:05, 27 June 2014

Description

MosquitoNR is a noise reduction filter designed for mosquito noise, which is often caused by lossy compression such as MPEG.

This filter works as follows:

1. Compute low frequency components of the image.

2. Apply direction-aware blur (smoothing). This blur effectively reduces compression artifacts, but also breaks detail.

3. Restore the low frequency components to the blurred image.

MosquitoNR processes luma only, to correctly process chroma take a look at the example below.

Requirements

- AviSynth 2.5.8 or AviSynth 2.6.0 Alpha5 or greater

- Progressive input only

- Supported color formats: YUY2, YV12, YV16, YV24, YV411, Y8

** If you're using AviSynth 2.5.8, YUY2 and YV12 will be the only colorspaces supported.

- CPU with SSE2 support

Syntax and Parameters

MosquitoNR (clip, int "strength", int "restore", int "radius", int "threads")

int  strength = 16

Range: 0 - 32

Sets the strength of the blur.

Setting this value higher brings stronger noise reduction effect, but side effect will also become stronger.

int  restore = 128

Range: 0 - 128

Sets the rate of restoring.

If set to 0, no restoring is performed.

If set to 128, low frequency components of the blurred image is completely replaced with those of the original image, and runs slightly faster.

int  radius = 2

Range: 1 - 2

Sets the radius of the blur.

1 is faster, but will have insufficient effect in some cases.

int  threads = 0

Range: 0 - 32

Controls how many threads are used.

By default, threads is set equal to automatically detected number of processors.

Since this filter needs a lot of memory access, thread efficiency is not very good. Setting this value lower might improve overall processing speed.

Examples

MosquitoNR with default settings:

AviSource("Blah.avi")
MosquitoNR(strength=16, restore=128, radius=2, threads=0)

MosquitoNR processes only luma. If you want to process chroma too, you can write a script like the following, but there might be no noticeable change.

AviSource("Blah.avi")
MosquitoNR()
u = UtoY().MosquitoNR()  # In AviSynth 2.6, UtoY8() may be faster
v = VtoY().MosquitoNR()
YtoUV(u, v, last)

Changelog

Version      Date            Changes

v0.10        2013/03/14      - fixed a crash with AviSynth MT
                             - added support for YV16, YV24, Y411, Y8
                             - some speed optimizations
                             - added English documentation

v120210      2012/02/10      - initial release

Acknowledgments

This filter is a combination of flash3kyuu's AviUtl plugin "smoothing filter" and nilpo's AviUtl plugin "low frequency components protection filter".
This combination was proposed by POP@4bit. I thank all of them very much.

• flash3kyuu's web page (Japanese): http://www.geocities.jp/flash3kyuu/
• nilpo's web page (Japanese): http://nilposoft.info/aviutl-plugin/
• POP@4bit's web page (Japanese): http://pop.4-bit.jp/?p=3362

Links

• Doom9 Forum - MosquitoNR discussion.

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