View Full Version : Grape Smoother
High Speed Dubb
3rd November 2002, 02:03
Here is a simpler, faster temporal smoother. This one works by harnessing the power of fairies, who pour pixie dust onto noisy parts of the image.
http://students.washington.edu/ldubb/computer/GrapeSmoother_v1_0a.zip
Um... What it really does is look at temporal color differences. When colors change just a little, the filter decides that it’s probably noise, and only slightly changes the color from the previous frame. As the change in color increases, the filter becomes more and more convinced that the change is due to motion rather than noise — and the new color gets more and more weight.
It’s a pretty mild temporal filter (at least if you use it with reasonable settings), but is good at avoiding visible artifacts.
PS: I forgot to mention — This one works fine on any MMX capable computer.
SansGrip
3rd November 2002, 03:47
Here is a simpler, faster temporal smoother. This one works by harnessing the power of fairies, who pour pixie dust onto noisy parts of the image.
My noise goblins will destroy your fairies!
(Sorry, couldn't resist... :D)
High Speed Dubb
3rd November 2002, 04:18
There is actually some similarity between the Grape and Peach smoothers and your noise producing filters. Both the Grape and the Peach are written to preserve low level noise, for much the same reasons that you would want to add some.
That works well for broadcast material. I’m not sure how well it does for MPEG stuff, though.
jarthel
3rd November 2002, 04:21
It's really much faster than peach! also faster than temporalsmoother. :)
I'm running 1st pass at the moment.
jayel
soulfx
3rd November 2002, 04:25
I'll give it a shot, as I've noticed on animation material captured from broadcast streams that certain colors that should be solid and stay solid, sort of alternate a bit in color. Maybe this filter will help.
Does this filter help any with crosstalk? I'll be able to see when I check it out, but just wondering for now. I know you've done a great job with crosstalk filtering with Dscaler. When it comes to crosstalk and filtering you've got to be one of the experts.
Thanks :)
High Speed Dubb
3rd November 2002, 04:34
Grape smoother doesn’t help crosstalk at all. Peach Smoother’s spatial smoothing can reduce mild NTSC crosstalk a little if your capture resolution happens to be ~640x480i.
I do plan to move the DScaler comb filter over to AVISynth, but that’s a relatively complicated job — not because of the code, but because it needs to be documented very carefully in order for it to be useful. Messed up comb filter settings can cause very obvious artifacts.
I think I’ll call it Guava.
High Speed Dubb
3rd November 2002, 05:20
Now that I think about it, Peach Smoother’s spatial smoothing may well help a little with PAL crosstalk, too. Cool!
Unfortunately, the reason I qualify as an expert on crosstalk is that none of us are really familiar with it. All I know is what I read on the net. ;)
Richard Berg
3rd November 2002, 09:21
I think that goes for all of us, on most subjects... ;)
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