[linux-audio-dev] Paper on dynamic range compression

[Andres Cabrera]

Hi Steve,
> What's that glitch near the cursor? Is that a bug, or was it in the input
> waveform?
>   

There is a very odd glitch there... I just repeated the test and the 
glitch is produced by the plugin, apparently from a sample that is 
wrapped around when the amplitude = maximum but only when using 
Rezound.... The output generated by Audacity doesn't have this glitch.
> What immediatly strikes me as wierd is that you don't get that rippling
> effect in the attack, or at least it's not as pronounced. Without delving
> into the code too deeply, I think theres a bug, theres some interpolation
> factor that's calculated from the attack coefficient (ef_a), but then its
> later applied whether were in the attack segment or the decay segment.
Yes, it appears the rippling is only there when gain reduction starts to 
be applied. Maybe the envelope tracker takes a while to kick in? Maybe 
that's the reason why the rippling starts when gain reduction starts to 
be applied, since gain reduction is not applied from the start, but a 
little into the sound. Bear in mind that the images show the first peak 
of the sample (even though the sample scale might suggest some time has 
elapsed-the sample contains some silence at the beginning)


> ope function. But I'm not really
> sure, as theres no comments in the code (bad Steve, no biscuit).
>
>   
Thanks for having a look.

Cheers,
Andrés