mfbatch

mfbatch is a command-line tool for batch-editing FLAC audio file metadata. It reads a directory of FLAC files, extracts the existing metadata to an intelligent text file format that the user can modify to update a large number of files and dynamic per-file metadata with a minimal number of edits.

mfbatch is a front-end for metaflac(1) which must be installed on the system.

Motivation

I've been reorganzing my sound effects library recently and have had to edit a large number of FLAC files, adding and editing descriptions, normalizing fields etc. and this is one of the tools I've come up with for updating a large number of FLAC files in an easy way quickly. It works completely in the command line and is designed to be used with your favorite text editor.

Workflow

1) Create a new MFBATCH_LIST file for a directory of FLAC files.

$ cd path/to/my/flacs 
$ mfbatch -c 

mfbatch will scan the current working directory and all subdirectories recursively. You can use a -p option to switch to another directory before scanning.

2) Edit the MFBATCH_LIST file in your $EDITOR.

$ mfbatch --edit

The MFBATCH_LIST file will contain a transcript of all of the flac files in the selected folder along with their current metadata.

:set ALBUM 'Test Album 1'
:set ARTIST 'Test Artist'
:set DESCRIPTION 'Tone file #1, test tone 440Hz'
:setp TITLE DESCRIPTION "^Tone file #(\d+).*" 'Tone \1'
./tone1.flac

:set DESCRIPTION 'Tone file #2, also 440Hz'
./tone2.flac
:unset DESCRIPTION

:set DESCRIPTION 'Tone file #3'
./tone3.flac

The MFBATCH_LIST format allows you to set metadata once and then write values to a run of files all at once. Several commands are available to manipulate the metadata written to the files.

3) After you've made the changes you want to make, write them to the files.

$ mfbatch -W

Writing metadata is interactive, mfbatch will display the metdata to be written to each file and metadata can be edited interactively at a prompt before writing.

Limitations

• Does not support newlines in field values. This is mostly by choice, newlines don't offer any benefit in my preferred sound library programs but this wouldn't be a tough feature to add if anyone needed it.
• Does not support multiple artwork types, everything is stored as type 3/ (album artwork-front).
• Can only store unique field keys, field values of the same key overwrite old values. This is also something that is tailored to my use-case and could be changed if there was interest in doing so.