unflac

A command line tool for fast frame accurate audio image + cue sheet splitting.

This project is started mostly out of frustration over supporting split2flac with all the external dependencies and their quirks.

Installation/upgrade and running

You need Go installed.

go install git.sr.ht/~ft/unflac@latest
~/go/bin/unflac -h

Dependencies

• ffmpeg (ffprobe command is also used, part of ffmpeg package)

Yeah, that's it.

Some useful options

• Set a specific sample format and rate for output files:

  unflac -F -sample_fmt -F s16 -F -ar -F 192000 ...

  See ffmpeg -sample_fmts. man ffmpeg contains a lot more.

Output file naming

To set a custom output file naming use -n option (run unflac -h to see the default value). The format of the argument is described here.

Elem - a function that replaces invalid file path characters with ones that look (almost) the same but valid

.Input.TrackNumberFmt - track number printf format (it's either "%02d" or "%03d" depending on the number of tracks)
.Input.Composer       - composer (can be empty)
.Input.Performer      - performer (can be empty)
.Input.SongWriter     - song writer (can be empty)
.Input.Title          - title, that's album name in general (can be empty)
.Input.Genre          - genre
.Input.Date           - date
.Input.TotalTracks    - total number of tracks
.Input.TotalDisks     - total number of disks, 0 if there is only one disk
.Input.Artist         - a special handy field that is selected based on Composer/Performer/SongWriter; is never empty

.Track.Number         - track number
.Track.DiskNumber     - disk number, 0 if there is only one disk
.Track.Composer       - composer (can be empty)
.Track.Performer      - performer (can be empty)
.Track.SongWriter     - song writer (can be empty)
.Track.Title          - track title
.Track.Artist         - a special handy field that is selected based on Composer/Performer/SongWriter; is never empty

TODO

• copying cue, log, images over to the destination
• clean up on errors
• replay gain
• support multiple artist/performer/composer?

DONE

• basic splitting
• tagging
• split to other formats (ogg/vorbis, mp3)
• parallel extraction
• support more input formats (wavpack, wave, mac)
• get the artist/performer/composer right
• multi-disk cue sheets support
• detect cue sheet encoding and convert to utf8
• an option to format the output path in a specific way

NOTES

• using id3 v2.3 tags because it seems basically no software reads id3 v2.4