SDL_audiolib - An audio decoding, resampling and mixing library.

This is a small and simple to use C++ library for playing various audio formats. It is a thin (-ish) wrapper around existing resampling (like SRC or SoX) and decoding libraries (like libmpg123 or libvorbis.)

I wrote it as my personal replacement for SDL_mixer, due to SDL_mixer's lack of multiple music streams, limited audio format support and poor resampling quality.

The API and ABI are not finalized (not sure if they'll ever be) and it's C++-only at the moment. You will find what looks to be the beginnings of an SDL_mixer drop-in replacement implementation, but it's not actually implemented to any useful extent and will probably be removed in the future.

As the name implies, it uses SDL to access the audio hardware.

Most popular audio formats are supported:

• Vorbis (libvorbisfile or libsndfile)
• Opus (libopusfile or libsndfile)
• MP3 (built-in through bundled dr_mp3, or through external libmpg123)
• Musepack (libmpcdec)
• FLAC (built-in through bundled dr_flac, or through external libFLAC or libsndfile)
• WAV and related formats (built-in through bundled dr_wav, or through external libsndfile)
• MIDI (FluidSynth, BASSMIDI, WildMIDI or libADLMIDI)
• MOD-based music formats (libopenmpt, libxmp or libmodplug)

You can also write your own decoders and resamplers by subclassing Aulib::Decoder and Aulib::Resampler.

Using the library is fairly simple:

#include <Aulib/DecoderVorbis.h>
#include <Aulib/ResamplerSpeex.h>
#include <Aulib/Stream.h>
#include <SDL.h>
#include <iostream>

int main()
{
    // The library uses std::chrono for durations, seeking and fading.
    using namespace std::chrono_literals;

    // Initialize the SDL_audiolib library. Set the output sample rate to
    // 44.1kHz, the audio format to 16-bit signed, use 2 output channels
    // (stereo), and an 8kB output buffer.
    if (Aulib::init(44100, AUDIO_S16SYS, 2, 8192) != 0) {
        std::cerr << "Couldn't initialize audio: " << SDL_GetError() << '\n';
        return EXIT_FAILURE;
    }

    // Create an audio stream that will play our Vorbis file using a Vorbis
    // decoder and a Speex resampler.
    Aulib::Stream music("music.ogg",
                        std::make_unique<Aulib::DecoderVorbis>(),
                        std::make_unique<Aulib::ResamplerSpeex>());

    // Play it once with a fade-in of 700 milliseconds.
    music.play(1, 700ms);

    // Wait while the music is still playing.
    while (music.isPlaying()) {
        SDL_Delay(200);
    }
    
    // Shut down and clean up. Calling this manually is optional, since the
    // library will call this automatically when the program exits.
    Aulib::quit();
}

For further details, read the API reference.