Re: Noise Reduction
Re: Noise Reduction
- Subject: Re: Noise Reduction
- From: Seth Willits <email@hidden>
- Date: Tue, 11 Sep 2012 16:39:07 -0700
In trying to figure out what those programs did, I came across the Noise Gate article on Wikipedia which mentioned this (with frequency profiling) is how Audacity works, but in retrospect I see now that the "Noise Gate" refers specifically to the simple threshold, and the frequency-specific threshold values is an additional step and it was just on the same page.
I wish I had the time to fully understand the application of the FFT and could write this myself. I understand just enough to know that I _could_ do it, but I'm sure it'd take me way longer than I am willing to dedicate to it at the moment. An example like this using Accelerate.framework and Core Audio would be amazing. I briefly thought about looking at Audacity but if the code is *anything* like the UI, it'd be a nightmare to try to understand. :-)
(iZotope, as Rick suggested, has a bunch of things available to license, so I've sent them an email. Not sure why I didn't find them in all of my Google searches.)
Thanks,
--
Seth Willits
On Sep 11, 2012, at 4:28 PM, Kevin Dixon wrote:
> Actually a Noise Gate is a much simpler algorithm, in which signal
> with less than a specified threshold is driven to silence. In this
> case, it will not affect the signal greater than the threshold, so
> there will be no noise reduction when signal is present.
> The "noise profiling" features in Audacity and the like use some sort
> of frequency-domain transform to try to remove the sampled noise from
> the entire track. You may want to look at the Audacity source (open
> source!) to see how this is implemented
>
> -Kevin
>
> On Tue, Sep 11, 2012 at 10:35 AM, Seth Willits <email@hidden> wrote:
>>
>>
>> I have a need to apply some filtering to an audio track to cut out the background hiss/noise. I believe what I'm after is a Noise Gate. In Audacity and Amadeus Pro there is a feature to do this, where you select a region which has just the background noise, it profiles it, and then you can apply the filter to the entire track. I figured something like this would be commonly available from somebody as an Audio Unit (if not Apple themselves), but I haven't found one.
>>
>> Anybody know of a go-to solution for this?
>>
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