mirkosp wrote:As a side note, I think Mister Hatt has a standalone fft3dgpu application which runs faster than the one in avisynth... if he's willing to share, you might be interested in it.
It's 64 bit linux only and requires ICC, I guess I could share if I can find where I committed it.
Don't use HQDN3D ever, it is insanely destructive. I think I once gave mirko a rundown on how filters like fft3d actually work, and I'll write one here so that you understand how to use the sigmas. Maybe someone will want to split and sticky, idk.
The haloing you got was due to having too strong a sharpen pass, I don't even use the sharpen feature at all.
FFT3D filter is a frequency domain filter. What that means is that a fast fourier transform of the video (to simplify it a bit and make things faster) is applied and a resulting frequency domain graph is generated. This is done with FFTW, a pretty sweet adaptive fourier transform library, however FFT3D uses quite an old version of it and without any of the really nice threading stuff for SPEED. FFT3D then applies a mask of blocks to your video, where each block overlaps a bit, and then each individual block is run over by the FFT to create the frequency domain graph.
Each block is then spectrum filtered according to your sigmas. Each sigma value corresponds to a specific 'size' of noise in your video. Sigma is for large blocks, sigma2 for smaller ones, sigma3 for things like dirt, and sigma4 for mosquito noise. You can also tweak the block sizes and planes and other things used. A good way to increase speed is to only filter the luma.
Once the graph is done, some inverse algorithms kick in and apply it to your actual image. That should cover enough for you to figure out how to use the thing. I would advise starting with low levels of sigma, 0.8 is common for me to use on most anime if it is on the heavier side of noisy. sigma=0.6,sigma2=0.4 is pretty much GOLD for contrasharpening stuff. Note that the last sigma value you define is what all subsequent values will be, so sigma=0.6 will set sigma2/3/4 as the same, while sigma=0.6,sigma2=0.4 will set sigma3/4 as 0.4 too. bt=4 is a good setting to have as well, and for full processing, plane=4.