resample_data.zsh

#!/bin/zsh
zmodload zsh/mathfunc

function random_string() {
    echo `cat /dev/urandom | env LC_CTYPE=C tr -cd 'a-f0-9' | head -c 6`
}

files=`find data_200ms/audio -name \*.wav`
total=`echo $files | wc -l | tr -d ' '`

for file in `echo $files`
do
    count=$((count+1))
    echo -ne "processing file $count/$total\r"

    fn=`basename $file`
    prefix=${fn:0:1}

    start_sec=0
    step=0.025

    for i in {0..7}
    do
        fn=`random_string`
        f1=data/audio/${prefix}_${fn}.wav
        f2=data/specs/${prefix}_${fn}.png
        sox $file $f1 trim $start_sec $step spectrogram -x 128 -y 128 -w Hamming -r -o $f2

        start_sec=$((start_sec + step))
        start_sec=`printf "%0.3f" start_sec`
    done
done

echo -ne '\n'