question about included filters

[chsmn]

forgive me if this has been asked before. Why is there three filters under each individual filter level(little, medium, heavy) in the gknot script file but only one filter per level is used?

# DENOISING: choose one combination (or none)
# 1) little noise
#Temporalsoften(2,3,3,mode=2,scenechange=6)
#mergechroma(blur(1.3))
#FluxSmooth(5,7)
#
# 2) medium noise
#Temporalsoften(3,5,5,mode=2,scenechange=10)
#Convolution3d("moviehq")
#FluxSmooth(7,7)
#
# 3) heavy noise
#Temporalsoften(4,8,8,mode=2,scenechange=10)
#Convolution3d("movielq")
#FluxSmooth(10,15)

Is that just to let the user manually switch to one of the other ones if they want?

also, why is undot always on by default, will it have any negative results on sources that do not need it?

One last question. I tried out all of gknots denoiser filters on a grainy dvd source and the only one that made a very noticeable difference was Temporalsoften(4,8,8,mode=2,scenechange=10), the other ones i had trouble telling even from the unfiltered. Is this right or should filters such as Convolution3d("movielq")be making as much of a difference as tempralsoft? does anyone know any really agressive convolution settings I can use to make sure this filter is working properly?

[manono]

Hi-

Is that just to let the user manually switch to one of the other ones if they want?

Yes. You have one default filter for each category, but some people prefer other filters to accomplish their goals. The choice is there if you want it. TemporalSoften is a pure temporal filter (Duh!), while C3D and FluxSmooth are combination spatial and temporal smoothers. If you'd like to see some speed and compression comparisons between different denoising filters, then work your way through this (http://forum.doom9.org/showthread.php?s=&threadid=51181) and this (http://forum.doom9.org/showthread.php?s=&threadid=62332&highlight=Undot).

why is undot always on by default

Because it only does good (in making the source a little bit more compressible, and in removing a bit of mosquito noise), and does no harm. Plus, it's fast and doesn't slow you down much. There's more information in this (http://forum.doom9.org/showthread.php?s=&threadid=63421&highlight=Undot+Default) thread.

...the only one that made a very noticeable difference was Temporalsoften(4,8,8,mode=2,scenechange=10)

And you're trusting your eyes to tell the differences? Run 3 compress tests, one with each default denoiser. Then compare the resulting percentages. That Heavy Noise TemporalSoften setting is too strong in my opinion, and leaves artifacts behind. Maybe it's OK for noisy captures, but I'd never use it on a DVD.

[chsmn]

...the only one that made a very noticeable difference was Temporalsoften(4,8,8,mode=2,scenechange=10)

what i'm saying is, that filter seemed to eliminate all the grainy noise while with the other ones, most of this noise was still visible.

[piscator]

Originally posted by chsmn
...the only one that made a very noticeable difference was Temporalsoften(4,8,8,mode=2,scenechange=10)

what i'm saying is, that filter seemed to eliminate all the grainy noise while with the other ones, most of this noise was still visible.

It's indeed supposed to do that, but at a (huge) cost. Besides noise, also details are removed from the source and prolly the result will be a lot more blurry than the source (both things I don't like). For the filter-happy people around here, they compensate that with Sharpen filters and dozen more possibilities.

Note that removing noise will always result in removing details in some degree from the source too; it's just a question of what annoys you more: the noise or the lack of details :D

greetz,
Piscator