[LAD] Normalize and Cut Wav

[Lorenzo Sutton]

Hi,

Alfs Kurmis wrote:
> Hi experts.
>
> I have started my small project - mp3 database for radio.
> http://martini.pudele.com/radio/mp3_database/mp3_database.html
>
> How do i normalize by peak [not RMS] and trim silences in begin and 
> end of WAV files ?
> Silences somewhere in middle of file i wanna leave untouched.
For normalization you can look at normalize [1] (aka normalize-audio on 
some distributions) it has a --peak option.

Lorenzo.

[1] http://normalize.nongnu.org/README.html
>
> I wanna in first step detect MAX sample in whole WAV file.
> For example we gottaMAX sample 10 000, then Apmliefier_coefficient 
> will be 32 000/10 000 = 3,2 .
>
> In second step i wanna trim silences at begin and below -80 dB [or 2 
> bit noise]
> For this in same file each sample multiple by Apmliefier_coefficient , 
> and see - result is over -80 dB or not.
> If not, then first N samples will not written in trimmed file, but 
> first sample that is over -80 dB [in any channel] ,
> and all further samples written in new file.
> Now we must just follow which sample [in any channel] is over -80 dB.
> After write is complete, we can just truncate after last sample that 
> was over -80 dB, and write header.
>
>
> So far i have found SOX vanna reverse da file for end silence trim, 
> and for each step produce tmp file.
>
> Is here C API , program, script, way to do so what without any 
> temporary files ?
>
> I have written script for normalize, but what ir best way for normalize ?
> What about mp3 and ogg  automatic normalize and frames trim ?
>
> Tnx in advance
> Alf
>
> ====
>
> #!/bin/bash
>
> for i in *.wav; do
>
>  val=${i%.wav}
>  echo "** Check peak for $i **"
>
>   ampl=`sox "$i" -t wav /dev/null stat -v 2>&1`
>   waveaus=${i%.wav}.wave
>
>   wert1="1.1";  wert2=$ampl;
>   wahr=$(echo  "$wert1 >  $wert2" | bc)
>   if  [ $wahr = 1 ]; then
>     echo "  $wert1 > $wert2 , Do Nuthin"
>   else
>     echo "  $wert1 <= $wert2 , Do process"
>     echo "** Amplifying volume by  -=$ampl=-  to fake a normalize   
> $val.wav  --  $waveaus"
>     ampl2=$(echo $ampl*0.9995 | bc -l)
>     echo "ampl2 = $ampl2"
>     sox -v $ampl2  "$i"  -t wav  "$waveaus"
>   fi
>
> echo ""
>
> done
>
>
>
> ----
>
>
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