[ecasound] -ev or -ea option overdid it

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Subject: [ecasound] -ev or -ea option overdid it
From: Christopher Taylor (cstaylor@thedial.com)
Date: Sun Feb 27 2000 - 06:08:09 EET

I used the -ev option like this...

   ecasound -i infile.wav -o infile.wav -ev

in order to determine the normalization level. The -ev option returned
this...

   (audiofx) -- End of statistics (counters reseted)--
   (audiofx) Max amplitude 0.94403; signal can be amplified by 105.92875%.

so, I fed the value '105.92875' into the -ea option as follows...

   ecasound -i infile.wav -o outfile.wav -ea:105.92875

Now, when I listen to the resulting waveform, there were pops. So, I tried
truncating the amplify-% argument to the -ea option so that it didn't
amplify it _completely_. This wavform does not have to pops. Below, I have
screenshots of the waveforms with the WAV files corresponding to those
waveforms.

So, I am thinking that this is a bug with the -ea or -ev options. Are they
a little bit off? Why would the -ev option give a value that would, in
fact, cause clipping of the waveform when passed to the -ea option? It's a
slight discrepency, and I could correct it for my own purposes, but I
thought it might interest you.

---------------------------------------------------------------------------
Clip 1:
amplify-%: 105.92875
wav file (557kB): http://ezln23.thedial.com/tmp/all.wav
waveform image: http://ezln23.thedial.com/tmp/all.gif

Clip 2:
amplify-%: 105.9
wav file (557kB): http://ezln23.thedial.com/tmp/1059.wav
waveform image: http://ezln23.thedial.com/tmp/1059.gif

Clip 3: (original clip)
amplify-%: none
wav file (557kB): http://ezln23.thedial.com/tmp/1000.wav
waveform image: http://ezln23.thedial.com/tmp/1000.gif
---------------------------------------------------------------------------

BTW, I have written a perl script which does normalization/compression and
mp3 encoding based on ecasound. If you want the source, I'll send it to
you. This way, I want have to constantly turn my volume up and down as I'm
listening to my mp3's.

Thanks,

CT 

-- 
Christopher Taylor <chris@thedial.com>  theDial
Director of Research and Development    http://www.thedial.com/
3131 Elliott Ave, Suite 750             phone: (206) 352-8200 x2002
Seattle, WA 98121                       cellular:  (206) 409-3394

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