ffmpeg noise reduction

[teddg]

Is there a noise reduction feature for x264 when using ffmpeg? I want to increase video compressibility.

*There's a -nr switch that's no longer documented (http://ffmpeg.mplayerhq.hu/ffmpeg-doc.html). Is it depreciated? Is there documentation on it somewhere? I think I read somewhere that it's not very good for single pass excodes.
*There's -vbsf noise ... but it crashes. Is there documentation or a usage example - don't even know what it's supposed to do for sure.
*Any other undocumented nr features? in x264?

[Dark Shikari]

x264 has the same nr as ffmpeg, just a whole lot faster.

[ToS_Maverick]

how good is the built-in nr? is it comparable to another avisynth filter? if yes, which one is compareable/similar?

[Dark Shikari]

It's like a crappy frequency-domain non-overlapped motion-compensated denoiser. Maybe a bit like MCdegrain with no overlap.

[teddg]

It's like a crappy frequency-domain non-overlapped motion-compensated denoiser. Maybe a bit like MCdegrain with no overlap.

Thanks for the info.

I ran a bunch of tests last night and got size reductions of up to 30%. The biggest size reductions came on grainy films at a low crf. I haven't looked closely at image quality or encoding speed yet, but nothing jumped out.

Size reduction, typical example, ffmpeg -nr 0 to 1500:
nr crf24 crf27
0 0.00% 0.00%
100 5.98% 2.80%
500 15.00% 8.12%
1000 17.84% 10.39%
1500 18.95% 11.39%

It would be nice to know why -nr this isn't documented. Is it being replaced by something else?

[Dark Shikari]

It would be nice to know why -nr this isn't documented. Is it being replaced by something else?Looks to me to be in both the ffmpeg and x264 help pages...

[teddg]

Looks to me to be in both the ffmpeg and x264 help pages...

Where are they? I must be looking in the wrong place :(
*nothing here: FFmpeg Documentation (http://ffmpeg.mplayerhq.hu/ffmpeg-doc.html)
*or here (http://www.google.com/search?q=noise+reduction+site%3Affmpeg.mplayerhq.hu&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a)
*ffmpeg -h gives "-nr <int> E.V.. noise reduction"

[Dark Shikari]

*ffmpeg -h gives "-nr <int> E.V.. noise reduction"Guess you answered your own question then? :p

[teddg]

Guess you answered your own question then? :p

You call that documentation?

According to some post on the internet somewhere, I forget where, but it was somewhere on the Internet, some guy said the -nr setting goes up to 10000, or maybe it was a gal, I forget. Actually, it could have been a dog. :p

[Sagekilla]

Yep, it tells you that the -nr switch takes a whole number as a parameter to apply noise reduction :)