FLAC-TRIM is a powerful bash script to trim, normalize, encode, save cover of FLAC, MP3, M4A and OPUS files.
It also compile from source latest version of FFMPEG with libfdk_aac and download all dependencies to run.
This script works very good with Spotify Downloader
wget https://raw.githubusercontent.com/mapi68/flac-trim/master/flac-trim.conf
wget https://raw.githubusercontent.com/mapi68/flac-trim/master/flac-trim.bash
chmod +x flac-trim.bash
./flac-trim.bash