Denoising audio in avisynth

Don't know what kind of noise you have, but if you think a simple lowpass filtering will help, then that is already implemented in v2.05 of avisynth. Please refer to for recent changes and new cvs builds.

Hi hakko504, there's a Cool Edit Filter with which you can make a Profile of your noise and the remove exactly _this_ kind of noise from your clip. You make this by selecting some seconds of silence in your clip - a part where only the noise is audible - and then let the filter analyse this part. Then you can change settings like strength, precision, masking, bla bla an apply the filter with your noise-profile to the whole clip. There are screenshots and soundclips on the syntrillium-homepage (makers of Cool Edit) which illustrates this (and other) denoising-filters: I think lowpass filtering can't compare to that. Try it; there's a tryout-version of Cool Edit. Btw. other Audio Apps have this sort of denoising-filters too. bye, Malcolm

This feature is not very easy to do, since it involves high-precision FFT filtering, and that's not easily done. For all you who wants to code, but don't know what it does, it's something like this: CoolEdit generates a frequency response pattern from the "clean noise" is recieves. When this is done, it uses this frequency pattern to create a filter, that removes only the frequencies found in the noise, thus (in principle) leaving all non-noise untouched.

there are good audio editing tools out there than using avisynth filters. Jayel

Use . I have not tested it, but it look good.

ffdshow has "blind" noise removal filter so always ffdshow can be used inside Avisynth.

Any script examples of using it ?

ffdshowAudio ("name of profile in ffdshow") or ffdshowAudio ("name of profile in ffdshow", options "name of parameter and value for parameter") - name of the parameter and value need to be discovered form ffdshow saved profile - just save exactly same profiles but with different values. small explanation is in avisynth documentation - audio processing in ffdshow can introduce some delays in audio - need to be corrected by DelayAudio()