Lossless audio

Lossless compression is a format that allows the original file to be perfectly reconstructed for the file.
Examples of lossless audio formats are:

• FLAC - Free Lossless Audio Codec (.flac)
• ALAC - Apple Lossless Audio Codec (.m4a)
• Monkey's Audio (.ape)
• WMA Lossless - Windows Media Audio Lossless (.wma)
• WAV - WAVeform Audio Format (.wav)

Converting ALAC to FLAC:

Install libav-tools:
sudo apt install libav-tools

Convert "audio.m4a" to "audio.flac":
avconv -i audio.m4a -acodec flac audio.flac

Bulk conversion of ALAC to FLAC (converts all ALAC files in a directory to FLAC):
for file in *.m4a; do avconv -i "$file" -acodec flac "${file%.m4a}.flac"; done;

Converting FLAC to ALAC:

Install libav-tools:
sudo apt install libav-tools

Convert "audio.flac" to "audio.m4a":
avconv -i audio.flac -acodec alac audio.m4a