FLAC for Haskell
- Aims of the project
- Provided functionality
- Quick start
- Related packages
This is a complete high-level Haskell binding to libFLAC—reference FLAC implementation.
As the maintainer of the C FLAC code base, I must say I’m impressed. Quite honestly, I think the C API is horrible.
Aims of the project
Here are several ideas the project follows:
Concentrate only on native FLAC format without messing with other audio formats or their flavors. This library is about FLAC only.
Be a complete interface for FLAC file manipulation in Haskell. “Complete” means that everything supported by the reference implementation should be supported by this package. This is in the hope to prevent fragmentation and proliferation of different libraries to work with FLAC with each of them covering only some 80% of functionality the library author needed and neglecting other 20%.
Be as efficient as the underlying C implementation, avoid adding any sort of overhead (memory/speed/or otherwise).
Provide idiot-proof API using type system to kindly guard against bad things, but not so much to remain beginner-friendly and simple.
Make invalid code and data unrepresentable.
FLAC is awesome and Haskell is awesome, surely there should be a way to achieve an even higher level of awesomeness by coding a safe Haskell API to the fast libFLAC library.
Seriously though, we
htaglib to work with
audio metadata, but it does not support a lot of FLAC-specific things I’d
love to manipulate. We
hsndfile, but I don’t
really want to read FLAC data into a buffer or Haskell
Vector. How simple
is it (if possible) to decode a FLAC file using that library? How simple is
it to figure out where to begin with such a task? With
decodeFlac def "myfile.flac" "myfile.wav"—done, average song in a fraction
Here we go:
Metadata—full support for reading/writing/deleting of all audio parameters, application data, seek tables, vorbis comments of all sorts, CUE sheets, and even pictures.
Stream decoder—simple interface for decoding to vanilla WAVE and RF64 (support for files larger than 4 Gb).
Stream encoder—a lot of options to tweak, everything that libFLAC has, but you can also use
defand just encode vanilla WAVE or RF64 file into native FLAC. Simple and efficient.
Right now there are three main limitations:
No Ogg FLAC support, and I do not plan to add it, but I’ll accept a PR adding support for Ogg FLAC.
It’s not possible to use custom callbacks for printing decoding/encoding progress in real-time and stuff like that. Not a big issue IMO, given that we get nice and safe API instead.
Only works on little-endian architectures so far, I’ll accept a PR lifting this limitation.
The best way to start using
flac is to take a look
at the Haddocks. Encoding and
decoding are so simple that even a baby could handle it, and for metadata
there are examples and a lot of details in the docs. Feel free to ask me a
question if you get stuck with something though.
The following packages are designed to be used with
flac-picture—add pictures to FLAC metadata easier.
Please kindly direct all issues, bugs, and questions to the GitHub issue tracker for this project.
Pull requests are also welcome and will be reviewed quickly.
Copyright © 2016–2017 Mark Karpov
Distributed under BSD 3 clause license.
- Documentation and metadata improvements.
- Added support for
DiscTotalVorbis comment field.
- Initial release.