Converting FLAC to ALAC on macOS

by Daniel Phillips

Categories

I’ve been looking for a way to batch convert FLAC files to ALAC (Apple Lossless) format easily on my Mac. I finally found a solution that does what I want: convert the file with equivalent quality and preserve metadata so I can drop the file right into the macOS Music app and play it.

Setup

You’ll need ffmpeg for this. If you don’t have it already you can install with the steps below:

  1. Start by installing Homebrew.
  2. Once you’ve got Homebrew installed, run brew install ffmpeg.
    • Once complete, open Terminal and enter ffmpeg to check the install. You should see a bunch of version information displayed in the terminal.

Convert a single file

  1. Open Terminal and cd to a directory containing a FLAC file.
  2. Enter the command ffmpeg -i input.flac -c:v copy -c:a alac output.m4a in the terminal, replacing input.flac with your input filename and output.m4a with your output filename.
  3. Run the command and wait. You should now have an output ALAC file!

Batch convert

This is based on a tip from Reddit. This builds on the command above to convert all files in a directory. Open Terminal, cd to your directory of FLAC files and enter the lines below:

export IFS=$'\n'
for x in `ls *.flac`; do ffmpeg -i $x -c:v copy -c:a alac ${x%flac}m4a; done

After a bit of a wait, you should now an ALAC file for each of your FLAC files.

Other notes

Interestingly, the macOS Music app won’t touch FLAC files but they open absolutely fine in Quicktime Player on macOS Sequoia.

macOS Sequoia already ships with a tool that can convert from FLAC to ALAC: afconvert. I tried this out but it didn’t work quite as well as ffmpeg on the first try. Firstly, it didn’t preserve metadata so the output ALAC file was missing tags like artist and album. It also didn’t automatically match the data format of the input file: 16-bit FLAC files were converted to 32-bit ALAC files by default. ffmpeg just did the right thing by default and handled the metadata.

Here’s the command I used if you want to experiment with afconvert:

afconvert -v -f m4af -d alac input.flac output.m4a

I might just be missing the right options to get this to work, but ffmpeg made this much easier so I’m sticking with that for now.