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. I wanna in first step detect MAX sample in whole WAV file. For example we gotta MAX 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 ----