Convert wav into mp3 files suitable for Alexa and Google Actions

convert.sh

#!/bin/bash

set -e

# Rename files to make them URL friendly
# https://formulae.brew.sh/formula/slugify

slugify *

# Trim silence at the beginning
# https://formulae.brew.sh/formula/sox

mkdir trimmed
for i in *.wav; do sox "$i" trimmed/"$i" silence 1 0.1 1% ; done
cd trimmed

# Convert to 24k for Google
# https://formulae.brew.sh/formula/ffmpeg

mkdir 24k
for i in *.wav; do ffmpeg -i "$i" -ac 2 -codec:a libmp3lame -b:a 96k -ar 24000 24k/"$(basename "$i" .wav)".mp3  ; done

# Convert to 16k for Alexa and normalize volume
# https://github.com/slhck/ffmpeg-normalize

mkdir 16k
ffmpeg-normalize *.wav -c:a libmp3lame -ar 16000 -b 48k -t -14 -of 16k --extension mp3