reflac

This is a script that allows you to recompress FLAC files while preserving their tags, intended for whole directories and for safety regardless of file name characters and encoding.

When storing FLACs on your big storage (desktop computer, NAS, etc), there may be a desire to compress them to the maximum extent possible, saving disk space and potentially many gigabytes for large collections. For this, you might use reflac --best on them.

However, slow and old systems might not have the capability to decode a maximally-compressed (or even the standard compression ratio) quick enough for real-time playback, and recompressing in a lower setting might be beneficial as well. This script started life, in a very rudimentary form for this purpose. The author used Rockbox on an old black/white display iPod, and found that flac -3 was the maximum he could compress FLACs while maintaining uninterrupted playback on the device.

Requirements

Both flac and metaflac need to be in your $PATH. These programs are normally packaged together as “flac” by distributions.

Running

Usage: reflac [OPTION]... [--] DIRECTORY...

 -h --help       Displays this help text
 -V --version    Displays the version of this program
 -v --verbose    Increases the verbosity.  Use once to display the FLACs
                 currently being processed, use twice for the full ‘flac’
                 output.
 -r --recursive  Recurse into directories.
 -n --no-action  Do not recompress.  With --verbose, displays a list of
                 files that would be processed.
 -0 --fast       Use the fastest, but worst, compression possible.
 -1..-7          Adjust FLAC compresion between these standard ranges.
                 The default is -5, the same as for flac itself.
 -8 --best       Use the slowest, but best, compression possible.

DIRECTORY should point ‘reflac’ to somewhere that contains *.flac
files. Optionally terminate the argument list with -- so that any
possible directory names don't get misinterpreted as arguments.

Bugs

What, bugs? This program is flawless! Joking aside, although the author tries to resolve in reflac itself, it is at the mercy of bugs and limitations from flac and metaflac.

Tag preservation in the light of malformed tags simply does not exist. Certain release groups use buggy software with the creation of their files and will trigger some grievances.

You might see something like this:

$ reflac FLAC
1-01 The Strange Green Pipe (Medley) [Mikeaudio].tag: ERROR: malformed vorbis comment field "Super Mario 64: Portrait of a Plumber",
       field contains no '=' character

reflac will not continue after the error, resulting in an untagged but recompressed FLAC file, with the temporary “.tag” file next to it. Manual repair by editing the tag file and metaflac is possible. The author works around the problem by using MusicBrainz Picard to retag the files, before using reflac.