# RtAudio
A set of C++ classes that provide a common API for realtime audio input/output across Linux (native ALSA, JACK, PulseAudio and OSS), Macintosh OS X (CoreAudio and JACK), and Windows (DirectSound, ASIO and WASAPI) operating systems.
By Gary P. Scavone, 2001-2023 (and many other developers!)
This distribution of RtAudio contains the following:
- doc: RtAudio documentation (see doc/html/index.html)
- tests: example RtAudio programs
- include: header and source files necessary for ASIO, DS & OSS compilation
- tests/Windows: Visual C++ .net test program workspace and projects
## Overview
RtAudio is a set of C++ classes that provides a common API (Application Programming Interface) for realtime audio input/output across Linux (native ALSA, JACK, PulseAudio and OSS), Macintosh OS X and Windows (DirectSound, ASIO and WASAPI) operating systems. RtAudio significantly simplifies the process of interacting with computer audio hardware. It was designed with the following objectives:
- object-oriented C++ design
- simple, common API across all supported platforms
- only one source and one header file for easy inclusion in programming projects
- allow simultaneous multi-api support
- support dynamic connection of devices
- provide extensive audio device parameter control
- allow audio device capability probing
- automatic internal conversion for data format, channel number compensation, (de)interleaving, and byte-swapping
RtAudio incorporates the concept of audio streams, which represent audio output (playback) and/or input (recording). Available audio devices and their capabilities can be enumerated and then specified when opening a stream. Where applicable, multiple API support can be compiled and a particular API specified when creating an RtAudio instance. See the \ref apinotes section for information specific to each of the supported audio APIs.
## Building
Several build systems are available. These are:
- autotools (`./autogen.sh; make` from git, or `./configure; make` from tarball release)
- CMake (`mkdir build; cd build; ../cmake; make`)
- meson (`meson build; cd build; ninja`)
- vcpkg (`./bootstrap-vcpkg.sh; ./vcpkg integrate install; ./vcpkg install rtaudio`)
See `install.txt` for more instructions about how to select the audio backend API. By
default all detected APIs will be enabled.
We recommend using the autotools-based build for packaging purposes. Please note that
RtAudio is designed as a single `.cpp` and `.h` file so that it is easy to copy directly
into a project. In that case you need to define the appropriate flags for the desired
backend APIs.
## FAQ
### Why does audio only come to one ear when I choose 1-channel output?
RtAudio doesn't automatically turn 1-channel output into stereo output with copied values to two channels, since there may be cases when a user truly wants 1-channel behaviour. If you want monophonic data to be projected to stereo output, open a 2-channel stream and copy the data to both channels in your audio stream callback.
## Further Reading
For complete documentation on RtAudio, see the doc directory of the distribution or surf to http://www.music.mcgill.ca/~gary/rtaudio/.
## Legal and ethical:
The RtAudio license is similar to the MIT License. Please see [LICENSE](LICENSE).