Re: [Audacity-devel] Getting back in to the swing (Observation of a P1 issue, Bug #286: Noise Removal)

[Gale A. <ga...@au...>]

| From Dawson Written <wri...@gm...> 
| Wed, 17 Sep 2008 01:46:17 -0500
| Subject: [Audacity-devel] Getting back in to the swing (Observation of a P1 issue, Bug #286: Noise Removal)
> James Crook wrote:
> >
> > Our four show stoppers are here:
> >
> > http://www.audacityteam.org/wiki/index.php?title=Release_Checklist
> That first P1issue (Noise Removal) happens when the project rate is set 
> to any value below 20480 Hz, which causes the int value, 
> mMinSignalBlocks, to round down to 0 at the top of 
> EffectNoiseRemoval::Initialize(). When EffectNoiseRemoval::GetProfile() 
> runs, the value of start is set to the same value as mHistoryLen and 
> since mSpectrums has mHistoryLen float-pointers allocated, it tries to 
> set the float value of min to the float of the dereferenced pointer in 
> the array entry (using the value of start as the index) one past the end 
> causing the access violation. (Hope that made sense.)
> 
> Setting the project sample rate to 20480 or above, will set 
> mMinSignalBlocks to 1 or higher and will not result in the violation.
> 
> Either a warning should come up saying a project must have a sample rate 
> of at least 20480Hz before noise removal profile is performed or the 
> math and code in effects/NoiseRemoval.cpp needs to be reviewed and 
> changed...

Thanks, Dawson. I'll link to your comments from the checklist. IMO the
maths needs changing. When people import a file for the first time, the
project rate should change to respect the rate of that file, if different, 
and it could be a low sample rate file. The project rate change happens
on Windows, though I gather it may not work on Linux, and it's 
currently a P2 issue on the Checklist to get this working consistently
on all platforms. 


Gale 
'