Re: [Audacity-quality] Proposal to rationalize and improve Normalize, Amplify & DC

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

| From Martyn Shaw <mar...@gm...> 
| Tue, 14 Jun 2011 00:17:46 +0100
| Subject: [Audacity-quality] Proposal to rationalize and improve Normalize, Amplify & DC
> On 13/06/2011 16:09, Peter Sampson wrote:
> > But I also note that Normalize with DC removal seems to take the same
> > time as DC removal on is own, which is not what I would expect.
> 
> Both need the pass over the audio to measure the dc offset.  The 
> second pass applies the dc removal and gain at the same time.  So both 
> these cases take 2 passes (not a separate one for dc removal and 
> amplify).  Does that make sense?

Largely so. But the second pass has "more to do" if applying gain as 
well as offset removal.  If this doesn't add anything much to the time
taken then it suggests the best way to apply DC offset may yet be to   
bundle it with other processes rather than have it as its own menu
item. 



Gale 


> > ----------------------------------------------------------------------
> > *From:* Martyn Shaw <mar...@gm...>
> > *To:* "for identification, characterization, and prioritization of
> > bugs." <aud...@li...>
> > *Sent:* Mon, June 13, 2011 12:40:25 AM
> > *Subject:* Re: [Audacity-quality] Proposal to rationalize and improve
> > Normalize, Amplify & DC
> >
> > Hi Peter
> >
> > Most of what you are measuring there are probably disk accesses, but
> > that is important. My claimed increase in performance did not involve
> > listening to my disk drive (and was only a minor claim).
> >
> > I have just committed something that should improve results iff you
> > are not doing dc removal (I removed a pass over the data in that case).
> >
> > If I am testing timings of functions A, B and C, I would test A then B
> > then C then A then B etc, and take at least 3 goes at each, to average
> > out changes in my PC (antivirus etc.). Are you doing that?
> >
> > On the Progress box, we normally do 2 passes over the audio for each
> > track, one for analysis and one for processing. The one for analysis
> > of amplitude is no longer required (in my changes) but the one for dc
> > offset still is. So removal of dc should take longer and just
> > normalising shouldn't be much different from Amplify. Is that what
> > you see once you get my recent changes?
> >
> > Thanks for your input here!
> >
> > TTFN
> > Martyn
> >
> >
> >
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