Single file audio playback and capture library.
Switch branches/tags
Nothing to show
Clone or download

README.md

mini_al

mini_al is a single file library for audio playback and capture. It's written in C (compilable as C++) and released into the public domain.

Features

  • A simple build system.
    • It should Just Work out of the box, without the need to download and install any dependencies.
  • A simple API.
  • Supports both playback and capture on all backends.
  • Data conversion.
    • Sample format conversion, with optional dithering.
    • Sample rate conversion.
    • Channel mapping and channel conversion (stereo to 5.1, etc.)
  • MP3, Vorbis, FLAC and WAV decoding.
    • This depends on external single file libraries which can be found in the "extras" folder.

Supported Platforms

  • Windows (XP+), UWP
  • macOS, iOS
  • Linux
  • BSD
  • Android
  • Raspberry Pi
  • Emscripten / HTML5

Backends

  • WASAPI
  • DirectSound
  • WinMM
  • Core Audio (Apple)
  • ALSA
  • PulseAudio
  • JACK
  • sndio (OpenBSD)
  • audio(4) (NetBSD and OpenBSD)
  • OSS (FreeBSD)
  • OpenSL|ES (Android only)
  • OpenAL
  • SDL
  • Null (Silence)

Building

Do the following in one source file:

#define MINI_AL_IMPLEMENTATION
#include "mini_al.h"

Then just compile. There's no need to install any dependencies. On Windows and macOS there's no need to link to anything. On Linux and BSD, just link to -lpthread, -lm and -ldl.

Simple Playback Example

#define DR_FLAC_IMPLEMENTATION
#include "../extras/dr_flac.h"  // Enables FLAC decoding.
#define DR_MP3_IMPLEMENTATION
#include "../extras/dr_mp3.h"   // Enables MP3 decoding.
#define DR_WAV_IMPLEMENTATION
#include "../extras/dr_wav.h"   // Enables WAV decoding.

#define MINI_AL_IMPLEMENTATION
#include "../mini_al.h"

#include <stdio.h>

// This is the function that's used for sending more data to the device for playback.
mal_uint32 on_send_frames_to_device(mal_device* pDevice, mal_uint32 frameCount, void* pSamples)
{
    mal_decoder* pDecoder = (mal_decoder*)pDevice->pUserData;
    if (pDecoder == NULL) {
        return 0;
    }

    return (mal_uint32)mal_decoder_read(pDecoder, frameCount, pSamples);
}

int main(int argc, char** argv)
{
    if (argc < 2) {
        printf("No input file.\n");
        return -1;
    }

    mal_decoder decoder;
    mal_result result = mal_decoder_init_file(argv[1], NULL, &decoder);
    if (result != MAL_SUCCESS) {
        return -2;
    }

    mal_device_config config = mal_device_config_init_playback(
        decoder.outputFormat,
        decoder.outputChannels,
        decoder.outputSampleRate,
        on_send_frames_to_device);

    mal_device device;
    if (mal_device_init(NULL, mal_device_type_playback, NULL, &config, &decoder, &device) != MAL_SUCCESS) {
        printf("Failed to open playback device.\n");
        mal_decoder_uninit(&decoder);
        return -3;
    }

    if (mal_device_start(&device) != MAL_SUCCESS) {
        printf("Failed to start playback device.\n");
        mal_device_uninit(&device);
        mal_decoder_uninit(&decoder);
        return -4;
    }

    printf("Press Enter to quit...");
    getchar();

    mal_device_uninit(&device);
    mal_decoder_uninit(&decoder);

    return 0;
}

MP3/Vorbis/FLAC/WAV Decoding

mini_al includes a decoding API which supports the following backends:

Copies of these libraries can be found in the "extras" folder. You may also want to look at the libraries below, but they are not supported by the mini_al decoder API. If you know of any other single file libraries I can add to this list, let me know. Preferably public domain or MIT.

To enable support for a decoding backend, all you need to do is #include the header section of the relevant backend library before the implementation of mini_al, like so:

#include "dr_flac.h"    // Enables FLAC decoding.
#include "dr_mp3.h"     // Enables MP3 decoding.
#include "dr_wav.h"     // Enables WAV decoding.

#define MINI_AL_IMPLEMENTATION
#include "mini_al.h"

A decoder can be initialized from a file with mal_decoder_init_file(), a block of memory with mal_decoder_init_memory(), or from data delivered via callbacks with mal_decoder_init(). Here is an example for loading a decoder from a file:

mal_decoder decoder;
mal_result result = mal_decoder_init_file("MySong.mp3", NULL, &decoder);
if (result != MAL_SUCCESS) {
    return false;   // An error occurred.
}

...

mal_decoder_uninit(&decoder);

When initializing a decoder, you can optionally pass in a pointer to a mal_decoder_config object (the NULL argument in the example above) which allows you to configure the output format, channel count, sample rate and channel map:

mal_decoder_config config = mal_decoder_config_init(mal_format_f32, 2, 48000);

When passing in NULL for this parameter, the output format will be the same as that defined by the decoding backend.

Data is read from the decoder as PCM frames:

mal_uint64 framesRead = mal_decoder_read(pDecoder, framesToRead, pFrames);

You can also seek to a specific frame like so:

mal_result result = mal_decoder_seek(pDecoder, targetFrame);
if (result != MAL_SUCCESS) {
    return false;   // An error occurred.
}

When loading a decoder, mini_al uses a trial and error technique to find the appropriate decoding backend. This can be unnecessarily inefficient if the type is already known. In this case you can use the _wav, _mp3, etc. varients of the aforementioned initialization APIs:

mal_decoder_init_wav()
mal_decoder_init_mp3()
mal_decoder_init_memory_wav()
mal_decoder_init_memory_mp3()
mal_decoder_init_file_wav()
mal_decoder_init_file_mp3()
etc.

The mal_decoder_init_file() API will try using the file extension to determine which decoding backend to prefer.