# PortAudio - portable audio I/O library

This is a fork of PortAudio that adds `Pa_RefreshDevice` functionality (see commit `1f01a3ddc05df7ee3bb3cad5ef960d335aff018b`), which allows runtime detection of audio device changes without restarting your application.

PortAudio is a portable audio I/O library designed for cross-platform
support of audio. It uses either a callback mechanism to request audio 
processing, or blocking read/write calls to buffer data between the 
native audio subsystem and the client. Audio can be processed in various 
formats, including 32 bit floating point, and will be converted to the 
native format internally.

## Documentation:

* Documentation is available at http://www.portaudio.com/docs/
* Or at `/doc/html/index.html` after running Doxygen.
* Also see `src/common/portaudio.h` for the API spec.
* And see the `examples/` and `test/` directories for many examples of usage. (We suggest `examples/paex_saw.c` for an example.)

For information on compiling programs with PortAudio, please see the
tutorial at:

  http://portaudio.com/docs/v19-doxydocs/tutorial_start.html
  
We have an active mailing list for user and developer discussions.
Please feel free to join. See http://www.portaudio.com for details.

## Important Files and Folders:

    include/portaudio.h     = header file for PortAudio API. Specifies API.	
    src/common/             = platform independent code, host independent 
                              code for all implementations.
    src/os                  = os specific (but host api neutral) code
    src/hostapi             = implementations for different host apis


### Host API Implementations:

    src/hostapi/alsa        = Advanced Linux Sound Architecture (ALSA)
    src/hostapi/asihpi      = AudioScience HPI
    src/hostapi/asio        = ASIO for Windows and Macintosh
    src/hostapi/coreaudio   = Macintosh Core Audio for OS X
    src/hostapi/dsound      = Windows Direct Sound
    src/hostapi/jack        = JACK Audio Connection Kit
    src/hostapi/oss         = Unix Open Sound System (OSS)
    src/hostapi/wasapi      = Windows Vista WASAPI
    src/hostapi/wdmks       = Windows WDM Kernel Streaming
    src/hostapi/wmme        = Windows MultiMedia Extensions (MME)


### Test Programs:

    test/pa_fuzz.c         = guitar fuzz box
    test/pa_devs.c         = print a list of available devices
    test/pa_minlat.c       = determine minimum latency for your machine
    test/paqa_devs.c       = self test that opens all devices
    test/paqa_errs.c       = test error detection and reporting
    test/patest_clip.c     = hear a sine wave clipped and unclipped
    test/patest_dither.c   = hear effects of dithering (extremely subtle)
    test/patest_pink.c     = fun with pink noise
    test/patest_record.c   = record and playback some audio
    test/patest_maxsines.c = how many sine waves can we play? Tests Pa_GetCPULoad().
    test/patest_sine.c     = output a sine wave in a simple PA app
    test/patest_sync.c     = test synchronization of audio and video
    test/patest_wire.c     = pass input to output, wire simulator

## Using with Node.js

This fork can be used with the [nodeaudio](https://andrewgundersen.net/repos/nodeaudio) Node.js bindings, which provide native audio I/O capabilities to JavaScript/TypeScript applications.

### Building PortAudio

Build portaudio:

    ./configure and make

At the time of writing (MacOS 12.1) I initially received build errors (-WError) about unused variables, so I had to remove -WError flag from the build rules.

Anytime the build configuration changes, make sure to run (see PortAudio docs):

    autoreconf -if

Use find command in usr/local/lib to see install state:

    find /usr/local/lib -name "libport*" -maxdepth 1

The default build of PortAudio sets an absolute install path (usr/local/lib) which causes issues if you want to package the .dylib in a project.  To fix this, use install_name_tool to rename the binary using a relative @loader_path:

    install_name_tool -id "@loader_path/libportaudio.dylib" libportaudio.dylib

Ideally, this would be set in the build config settings of PortAudio, but I haven't figured out how to do that yet.

### Using with nodeaudio

The [nodeaudio](https://andrewgundersen.net/repos/nodeaudio) bindings wrap this PortAudio fork to expose audio I/O capabilities to Node.js applications. Clone and build the nodeaudio project to get started:

    git clone https://andrewgundersen.net/repos/nodeaudio
    cd nodeaudio
    node-gyp rebuild

This will link against the PortAudio library you've built, allowing you to use audio functionality from JavaScript.

TODO: Sign on build
Of course, any binary (e.g. libportaudio.dylib) must be signed before distribution.