OpenAL Soft

OpenAL Soft is a multi-platform software implementation of the popular OpenAL 3D audio API. Its source code is based on the open-sourced Windows version that was originally available from the SVN repository at openal.org. The API offers audio features like distance attenuation, doppler shift, and directional sound emitters, which help create a virtual 3D audio environment. For more advanced audio effects, OpenAL Soft offers air absorption, low-pass filters, and reverb through the EFX extension. Additionally, the API facilitates audio streaming, multi-channel buffering, and audio capture for audio professionals and developers.

OpenAL Soft is specifically designed to replace or update the outdated OpenAL Sample Implementation (SI), which has been unmaintained for quite some time. The SI requires significant cleanup work, but after attempting to address some of the issues, the maintenance became overwhelming. Thus, OpenAL Soft was created by forking the old Windows version to create an accelerated ALSA version. Though that idea fell through, the software mixing code was ported to be cross-platform, with multiple output backends, including ALSA, OSS, DirectSound, and .wav writers. The API supports mono, stereo, 4-channel, 5.1, 6.1, and 7.1 output channels instead of the SI's 4-channel limit, and it offers extensions like AL_EXT_FLOAT32, AL_EXT_MCFORMATS, and ALC_EXT_EFX.

To use OpenAL Soft, your system must have CMake version 2.4 or newer. Installation is simple: extract the software, which will automatically create the openal-soft-/ directory. Next, navigate to the CMakeConf/ directory in your shell and run the command "cmake .." to configure it. If everything goes well, you can now build it using GNU Make or another suitable build tool for your system.

The latest version comes with a whole host of fixes and new features. For example, it fixes a DirectSound buffer lock issue on some cards, selects the output format based on the speaker setup, enumerates DirectSound devices with the ALC_ENUMERATE_ALL_EXT extension, and fixes initialization and unexpected shutdown issues. Furthermore, it offers a new option to duplicate stereo sounds on the rear channels, and the header alext.h is now more practical for extension usage. It is important to note that the release does not yet include the EFX types.

Overall, OpenAL Soft is an excellent alternative to the outdated OpenAL Sample Implementation, offering improved features and compatibility. The API supports a wide range of audio features, including advanced audio effects, audio capture, and audio streaming.