FaeryDust - FluxSmooth - TemporalCleaner

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• limit (1-8) determines the maximum amount FaeryDust can change each pixel by; if a pixel would have been changed by more than this value, it is changed by exactly this value instead. Raising this value will increase the strength of the smoothing (but may hurt details).

• IMPORTANT: The Dust filters do NOT support YV12. This is because they were written for AVISynth 2.0.x, which was incapable of working in the YV12 colorspace; a version for AVISynth 2.5.x was never coded. If you try to feed FaeryDust YV12 input, your application will suddenly quit without warning. Always convert to YUY2 first.
• IMPORTANT: The Dust filters do not autoload. Again, this is because they were written for AVISynth 2.0.x and not 2.5.x. To use them, you first have to load a plugin called LoadPluginEx2.dll (in a separate directory from your default plugins directory, because it will break autoloading otherwise); I've taken care of this for you in an autoloading .AVSI helper script. Then you manually load DustV5.dll by putting the following line before calling the filter: LoadPlugin("C:\avs25\plugins\DustV5.dll") (of course, replace the path given with the path to your AVISynth plugins directory).
• IMPORTANT: Do not call the Dust filters more than once in one script. This also means that if you use FaeryDust in a script, you can't use SpaceDust, PixieDust, or GoldDust in that same script.
• FaeryDust should probably be used after cropping and resizing, but I'm not sure about this.

• temporal_threshold (-1 to 255?) determines how close to the current pixel's value a temporal neighbor pixel has to be in order to be included in the averaging. Raising this value will increase the strength of the smoothing (but may introduce ghosting). If set to -1, then no temporal smoothing occurs (cannot be set to -1 with FluxSmoothT).
• spatial_threshold (-1 to 255?) determines how close to the current pixel's value a spatial neighbor pixel has to be in order to be included in the averaging. Raising this value will increase the strength of the smoothing (but may introduce blurring). If set to -1, then no spatial smoothing occurs (but in that case, you should just be using FluxSmoothT anyway).

Many of you may be looking at FluxSmoothST and wondering "WTH? That's a spatio-temporal smoother! Why is it on this page?" Well, in order to answer that, I have to explain the theory of operation of FluxSmooth.
FluxSmooth only corrects a pixel if it has a value that's either lower or higher than the values of BOTH its temporal neighbor pixels (a.k.a. the same pixel in the previous and next frames). SansGrip refers to these as fluctuating pixels, hence the filter's name. The idea is that such a pixel is more likely to be noise than signal.
So you see, in order to decide which pixels should be changed, FluxSmooth makes only temporal considerations, no spatial ones. That's why it goes on the temporal smoothers page.

In my experience, FluxSmooth (at least FluxSmoothST) is very good at preserving detail while still helping compressibility, and it would probably make a good filter to go before other, more heavy-duty smoothers. Personally, what I'd really like to see is another threshold that could be used to ignore pixels that are fluctuating by more than a certain amount... Back to top

• ythresh (1-255?) determines how close the previous pixel's luma has to be to that of the current pixel in order for averaging to occur. Vlad59 advises that this not be raised higher than about 8, in the interests of not introducing ghosting.
• cthresh (1-255?) determines how close the previous pixel's chroma has to be to that of the current pixel in order for averaging to occur. However, if the luma difference for a pixel is above ythresh, then this is ignored and the chroma is automatically left as is. So this parameter can normally safely be set higher than ythresh.

TemporalCleaner's theory of operation is very simple: if a pixel differs from the same pixel in the previous frame by less than a threshold, the pixel is replaced by the average of itself and the previous pixel. That's it (but see the note above about the chroma).
Personally, I haven't found TemporalCleaner to be as effective as the other temporal smoothers such as FluxSmooth. However, it's undeniably very fast, and I've never seen it introduce any artifacts or wreck any details at the default settings. Back to top