gregcman / a-sound-system

Play audio in Common Lisp using OpenAL, libsndfile/FFMPEG

Play audio in Common Lisp

Load audio with FFMPEG or libsndfile, and play it with OpenAL. FFMPEG supports a wide range of sound formats, but libsndfile is smaller and on quicklisp.

Technical details

/ffmpeg/:

• ffmpeg.lisp uses the ffmpeg API to load packets from sound files.

• ffmpeg-bindings.lisp is hand-written bindings to ffmpeg, because I could not find up-to-date bindings for ffmpeg in common lisp at the time.

/openal-and-ffmpeg/ :

• al.lisp is bindings to the OpenAL C API.

• openal.lisp sets up OpenAL for playing audio, as well as background threads for buffering audio data and polling OpenAL.

/musical-binaries/ :

• contains FFMPEG and OpenAL binaries for Mac, Windows 32-bit, Windows 64-bit, and linux.

• Audio player is openal but a different backend could probably be used.

Bugs

FFMPEG:

The AVFormatContext c structure might need some tweaking depending on the version, since it uses (in the C source code) c macros to detect the operating system, so the structure might be different on different operating systems. There is a #+darwin in one of the files in this project for mac osx, it worked last time, but is now commented out and somehow works on linux. I am too lazy to figure out what happened.