Could someone point me to formal papers or detailed algorithm descriptions behind Audacity’s noise reduction algorithm? I’ve seen the algorithm description at http://wiki.audacityteam.org/wiki/Noise_Removal , but I’d like a far more detailed description- I’d like to implement the Audacity algorithm in MATLAB, for the purpose of cleaning up speech contaminated with MRI noise.
I have noise reduction algorithm, It has some drawbacks. In this algorithm noise parameters calculated only for starting noisy frames,
when voice detected, that parameters(noise params calculated upto previous frame), applying on following frames. Here Not updating
the noise parameters for voice frames. I got improved results but not better. i got 30-40% results improvements(without noise reduction
800 passed(28.5%) out of 2800, with noise reduction 1140 passed (41%) ).
Can any one suggest me, in modifying algorithm to improve results or point me where i get better algorithm?
Moderator note: Ramesh, please do not double post - unfortunately we have had to implement post moderation to prevent a flood of spam much of it unpleasant and some of it downright dangerous. I removed the duplicate post for you.
I want to implement audacity noise removal code in C language, Is any one already implemented in “C” or
Can I find audacity Noise Removal code in “C” any where?
One doubt in the Algorithm, fft length (window size) is 2048, why it is? Is any reason to take this?. Can I take fft length
as 64 or 128. I think for lower block size resolution is more, and signal is analysed better.
Is it valid doubt. Please any one give me suggestion and help me in finding “C” code.
Yeah, and I do always read the same replys and wonder why they are not marked as read.
By the way, a shorter block size is definetly not better. The frequencies do smear much to much (forced smoothing).
1024 is good for speech and 4096 for music.
2048 is probably the best trade-off found so far.
One could work with different sample rates to evaluate this behaviour.
I am using audacity tool to remove noise from my wave files manually using GUI. But I have 1000’s of files, I need to do this using batch files or scripts.
Can anyone suggest me how to automate the Audacity noise removal through scripts, not using GUI?
"you can use Chains to process perhaps 1000 or 2000 files at a time. "
I am using chains to process more files in audacity tool to remove noise from my wave files. Here I am not profiling (not using “get profiling”) the noise to estimate the noise, In this case what it will do?, will it estimate noise from each stream or uses default noise profile?
If I want to estimate the noise profile for each stream (Get Profile), and need to remove noise from each stream using corresponding noise profile. Can you please suggest me is it possible through chains or any other ways (automated scripts in windows)?
If correct, that is clearly inappropriate, until we have “intelligent” noise reduction that gathers its own profile from each file.
Even if the profile happens to be appropriate for each file to be processed, it requires the user to create a prior profile file and to force the first file to be processed to be that profile.
I would use noiseprof then noisered in a SoX script on each file, carefully specifying the selection for noiseprof. As I understand it, this would grab a separate profile for each file. See: http://sox.sourceforge.net/sox.html .
Thank you very much for the code. Actually I am a new user of Audacity and the Noise reduction function of GUI works pretty well for me. However, either there are magic numbers in the code or I simply missed them, I cannot see where the 3 GUI free parameters (Noise reduction level (in dB), sensitivity and freq. smoothing (bands) are implemented. Also can you provide your PowerSpectrum function or any PS will do the job?
Thanks a lot again,