0.20-09 is released

It's been a while since GWC got some overdue attention.

Thanks to Robert Atwood for a fix to the audio playback hanging problem (which was better than my fix ;-) )

Thiemo Gehrke did some great work cleaning up config.in and Makefile.in (which were admittedly a mess).

The amplify function can now mix from either channel, so if you have a dropout in one channel and it's more or less monophonic you can try to mix in from the other channel. I'm firmly convinced most people will look at the amplify dialog and say "HUH -- how does that work?". I slapped the dialog in place really fast and I'm sure the descriptive text (or lack of ...) could use improvement.

Amplify also now can do a IIR (Infinite Impulse Response) lowpass filter. That was to solve my own problem where my monitor went into power save mode and I got a 14Khz "signal injection" into my audio file.

Also to solve one of my problems I added some code to create pink and/or white noise. I am working on a project where I don't have and portion of the track with no true signal. I had wondered for a while if you could used artificially generated noise as an estimate for the actual noise present in the audio track. Based on my test here, I was pleasently surprised! It turned out for me that white noise was better than pink noise to estimate the actual noise.

My other problem at the moment (on the some audio track), is there is a background hum that becomes audible after I remove the noise. So, I'm working on a way to specify which frequencies in the noise sample you want removed during denoising. I believe this can become an all-purpose lowpass/highpass/notch filtering mechanism using FFT as the basis.

Rob Frohne has ported GWC to Mac/OSX. He sent me his work and it should be a small effort to merge the code.

Happy new year to everyone. Let's hope for a peaceful planet in 2005.

Cheers,
Jeff

Posted by Jeff Welty 2005-01-10