Lindar

Library for Integrated Native Digital Audio Runtime.

A modular C audio library, developed for Elten and other audio work at Prowadnica Foundation.

Public preview

Public API, default config, module boundaries and package contents may change before 1.0. Not all target configurations have been fully tested yet.

Features

• Native playback and recording on Windows, Linux, macOS, Android and iOS.
• Seeking, looping, live PCM queues, mixing, routing, channel mapping, resampling and planar/interleaved PCM conversion.
• WAV/ADPCM, MP3, AAC, FLAC, Opus and Vorbis decoding/encoding; AIFF and Speex decoding; additional formats through system codecs and FFmpeg.
• Metadata and chapters; ID3, Ogg Opus and WAVE retagging.
• Filters, delay, reverb, modulation, dynamics, tempo/pitch control and parameter automation.
• Peak/RMS metering, FFT analysis, playback notifications and render-time profiling.
• HTTP/HTTPS, internet radio, HLS and Icecast/SHOUTcast broadcasting.
• VST3 effects and editors; MIDI-file synthesis with SF2 banks.

Idea

Lindar uses the same source and playback APIs in MCU firmware and desktop or mobile applications. The core can render PCM without an OS or heap; devices, codecs, networking and processing are selected at build time.

Allocations can use libc or application callbacks, and core objects support caller-provided storage. The application can pull PCM itself or let a device drive playback. Lindar's worker threads are optional. The C API uses opaque resource handles and supports FFI.

Architecture explains the audio types, graph and rendering model.

Packages

Package names and contents are provisional for the preview and may change before release. Each name identifies a CMake preset and library target.

Package	Contents
linda	Core only; no OS, workers or default allocator.
lindar_pitya	Graph, devices, files, queues and WAV/ADPCM.
lindar	Extended codecs, metadata, DSP, analysis, HTTP and SoundTouch.
lindar_quanta	Adds Bungee, ASIO, effects, MIDI, VST3 and FFmpeg.

To distinguish builds, it is recommended to retain the package names in binary filenames. For custom builds, use a name such as lindar_custom, lindar_xyz or another lindar_* variant.

Example

With the lindar package: play music.mp3 through a stereo mixer at half gain. Press Enter to stop.

#include "lindar.h"
#include "lindar_devices.h"
#include "lindar_files.h"
#include "lindar_graph.h"
#include <stdio.h>

int main(void) {
    if (LND_ConfigSet(LND_CFG_DEVICES_AUTO_OPEN, 0) != LND_OK ||
        LND_LibraryInit() != LND_OK) return 1;

    LND_SOURCE *source = LND_SourceCreateFile("music.mp3", 0, nullptr);
    LND_SOUND *sound = source ? LND_SourceEnsureSound(source, nullptr) : nullptr;
    LND_NODE *mixer = LND_NodeCreateMixer(2, 48000, 0);
    LND_DEVICE_INSTANCE *device = LND_DeviceInstanceOpen(LND_DEVICE_DEFAULT_OUTPUT);
    int result = 1;

    if (sound && mixer && device &&
        LND_SoundSetOutput(sound, mixer) == LND_OK &&
        LND_NodeSetParam(mixer, LND_PARAM_GAIN, 0.5f) == LND_OK &&
        LND_NodeConnect(mixer, LND_DeviceInstanceGetNode(device)) == LND_OK &&
        LND_SoundPlay(sound) == LND_OK) {
        puts("Playing music.mp3. Press Enter to stop.");
        getchar();
        result = 0;
    }

    LND_LibraryFree();
    return result;
}

More examples: examples/.

Documentation

• 1.0 release checklist
• Security policy
• Build and installation
• Architecture and module development
• Tests, benchmarks, MCU emulation and documentation tools

API behaviour and constraints are documented in include/. Generate the reference, module/package tables and example index with ruby tools/docs.rb; open build/docs/html/index.html. Requirements.

Contributing

Thank you for your interest in Lindar and for helping improve it.

See how to contribute and accept the CLA.

Licence

All original project content is licensed under the GNU Lesser General Public License, version 2.1 only (LGPL-2.1-only). Third-party code and assets retain their own licences.