Wwise is described as '"Wwise® is the most advanced, feature-rich interactive sound engine for games, bar none. Whether you're an indie or a multi-million dollar production, Wwise will work for you." - Audiokinetic.com' and is an app. There are five alternatives to Wwise for Mac, Windows, Linux, Android and Self-Hosted. The best Wwise alternative is OpenAL Soft, which is both free and Open Source. Other great apps like Wwise are PortAudio, RtAudio, FMOD Ex and SoLoud.
OpenAL Soft is an LGPL-licensed, cross-platform, software implementation of the OpenAL 3D audio API. It's forked from the open-sourced Windows version available originally from openal.org's SVN repository (now defunct).
PortAudio is a cross platform, open-source, audio I/O library. It provides a very simple API for recording and/or playing sound using a simple callback function.
RtAudio is a set of C++ classes that provide a common API for realtime audio input/output across Linux, Macintosh OS-X and Windows operating systems. RtAudio significantly simplifies the process of interacting with computer audio hardware.
FMOD is a proprietary audio library that plays music files of diverse formats on many different operating system platforms, used in games and software applications to provide audio functionality.
SoLoud is portable - the c/c++ code base is written in portable way, and the code has been used on various platforms including windows, osx, linux, as well as android and even ps4. (I'm not responsible for many of the platforms, though, and for licensing reasons, ps4 code is...
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