[music-dsp] Waveform Interpolation

[Nigel Redmon]

Maybe you missed the post (in my flurry of them yesterday), where I gave the link to

http://www.earlevel.com/main/2010/12/11/a-closer-look-at-upsampling-filters

When I posted, I had a problem with Opera and Firefox, but figured it out pretty quickly (my first look at Opera dragonfly debugger--worked great; I started out trying to debug on Firefox, had to download a separate debugger plug-in, and the whole browser became sluggish after enabling it--was glad my lack of patience had me give Opera debugger a try because it was a much better experience). In the magnitude computation, instead of testing for zero before the log, I tested for NaN--"not a number"--after, but log(0) returns a value called "-Infinity", not NaN. Chrome, IE, and Safari javascript engines were happy to use that value in downstream calculations correctly, but Firefox and Opera javascript crashed on it. All working fine now.


On Dec 11, 2010, at 9:38 PM, robert bristow-johnson wrote:

> On Dec 11, 2010, at 7:32 PM, Nigel Redmon wrote:
> 
>> OK, fixed the Firefox/Opera issue.
>> 
>> Lesson learned: javascript returns "-Infinity" for log(0), not "NaN", which I was checking for. Some javascript implementations don't mind doing math with -Infinity, some do.
>> 
>> 
>> On Dec 11, 2010, at 3:42 PM, Nigel Redmon wrote:
>>> ... and Firefox has issue with some things (linear interpolation and zero-order hold for some reason...
> 
> 
> now i'm back to not understanding what you're saying again.