Libcwav 3DS

libcwav is a library for playing (b)cwav files on the 3DS.

The goal of this library is to provide an interface for playing (b)cwav files in 3DS homebrew sofware. The way it is designed allows to play these files in non-application environments, such as 3GX game plugins or applets, as it provides support for the CSND system service. Unlike (b)cstm files which are streamed in chunks from their storage media, (b)cwav files are fully loaded into the linear RAM. Therefore, (b)cwav files are only meant for small sound effects. This library provides support for the ADPCM encodings, which heavily reduce the required memory to play the file.

Building

Make sure you have devkitpro installed and working.

Clone or download the repo and open a command prompt. Run make install and confirm there aren't any errors.
In your project makefile, add the following to the LIBDIRS line (or similar): $(DEVKITPRO)/libcwav
In your project makefile, add the following to the LIBS line (or similar): -lcwav if the already listed libraries start with -l or just cwav if they don't.
Add #include "cwav.h" and/or #include "cwav_file.h" in your source files to use the library.

You can check all the available function calls in the documentation provided in .h|cwav.h and cwav_file.h. Also, you can see an example application in example_libcwav.

User guide

CWAV Audio Encodings

The following audio encodings are supported.

PCM8/PCM16	Uncompressed 8/16 bit PCM. Useful if memory usage is not a problem.
DSP ADPCM	Lossy compression format, useful if the available memory is limited. Can only be played with DSP.
IMA ADPCM	Lossy compression format, similar to DSP ADPCM. Can only be played with CSND.

System Services

The following system services used to play the audio are supported.

DSP - Used by normal applications. Recommend to use this system service, as it properly supports suspending applications and sleep mode.
CSND - Used by applets to play audio. It has the advantage of playing audio on top of running/suspended applications, whitout causing any interferences.
- Use this system service if you want to play audio in applets or 3GX game plugins.
- Make sure to use cwavDoAptHook() or cwavNotifyAptEvent() to handle apt events (app suspend, sleep or exit).

Create (b)cwav files

You can use cwavtool to create (b)cwav files from other audio formats. It supports all possible encodings and loop points.

Changelog

v1.0 2021/01/27

Initial release.

Credits

libctru - CSND and DSP implementation.

3dbrew.org - (b)cwav file specification.