iora_codecs

General-purpose audio and video codec library for media encoding, decoding, and DSP processing. Built on the Iora C++17 framework. Supports both plain RTP (SIP) and WebRTC use cases.

Features

Audio Codecs

Codec	Sample Rates	Bitrate	License	Default
Opus	8-48 kHz	6-510 kbps	BSD-3	ON
G.711 u-law/A-law	8 kHz	64 kbps	Built-in	ON
G.722	16 kHz	48/56/64 kbps	BSD-3	ON
iLBC	8 kHz	13.3/15.2 kbps	BSD-3	ON
AMR-NB/WB	8/16 kHz	4.75-23.85 kbps	Apache-2.0	OFF
G.729	8 kHz	8 kbps	GPL-3.0*	OFF

*G.729 (mod_g729.so) uses bcg729 (GPL-3.0). GPL scope is confined to this module via RTLD_LOCAL isolation. Opt-in: -DIORA_CODECS_ENABLE_G729=ON

Video Codecs

Codec	Description	License	Default
H.264	OpenH264 (Cisco), Baseline/CB profiles	BSD-2	ON
VP8/VP9	libvpx, patent-free	BSD-3	ON
AV1	libaom encoder + dav1d decoder	BSD-2	OFF

DSP Processing

• Resampling -- arbitrary sample-rate conversion via libspeexdsp
• Audio mixing -- N-way conference mixing with N-1 semantics, three algorithms (average, saturating, AGC)
• Gain/volume -- linear and dB control with saturation clamping
• Voice activity detection -- energy-based VAD with hangover logic
• DTMF generation -- ITU-T Q.23 dual-tone synthesis (16 digits)
• DTMF detection -- Goertzel algorithm with ITU-T Q.24 twist limits
• WAV file I/O -- read/write standard RIFF WAV files, pipeline recording tap

Pipeline Orchestration

• DAG-based media processing graph with named stages
• Codec hot-swap during active sessions
• Per-stage latency and frame metrics
• Format negotiation with auto-inserted conversion stages
• Lifecycle management (Created -> Running -> Draining -> Stopped -> Reset)

Architecture

Layer 3  Pipeline     MediaPipeline, TranscodingHandler, AudioMixerHandler
Layer 2  Codec        ICodec, ICodecFactory, CodecRegistry, plugin modules
Layer 1  DSP          Resampler, AudioMixer, Gain, VAD, ToneGenerator, Goertzel, WAV
Layer 0  Core         MediaBuffer, MediaBufferPool, MediaClock, SampleFormat, PixelFormat
         (Iora)       Threading, timers, logging, config, lifecycle, crypto

Building

Prerequisites

• C++17 compiler (GCC 9+, Clang 10+, MSVC 2019+)
• CMake 3.20+
• Git (for submodules)

Quick Build

git submodule update --init --recursive
cmake -S . -B build
cmake --build build -j$(nproc)

Full Build (including AV1)

cmake -S . -B build -DIORA_CODECS_ENABLE_AV1=ON
cmake --build build -j$(nproc)

Minimal Build (Opus + G.711 only)

cmake -S . -B build \
  -DIORA_CODECS_ENABLE_G722=OFF \
  -DIORA_CODECS_ENABLE_ILBC=OFF \
  -DIORA_CODECS_ENABLE_AMR=OFF \
  -DIORA_CODECS_ENABLE_H264=OFF \
  -DIORA_CODECS_ENABLE_VPX=OFF
cmake --build build -j$(nproc)

CMake Options

Option	Default	Description
IORA_CODECS_ENABLE_OPUS	ON	Opus audio codec
IORA_CODECS_ENABLE_G711	ON	G.711 mu-law/A-law (built-in)
IORA_CODECS_ENABLE_G722	ON	G.722 wideband audio
IORA_CODECS_ENABLE_ILBC	ON	iLBC low bitrate codec
IORA_CODECS_ENABLE_AMR	OFF	AMR-NB/WB (patent encumbered)
IORA_CODECS_ENABLE_H264	ON	H.264 via OpenH264
IORA_CODECS_ENABLE_VPX	ON	VP8/VP9 via libvpx
IORA_CODECS_ENABLE_G729	OFF	G.729 via bcg729 (GPL-3.0, isolated)
IORA_CODECS_ENABLE_AV1	OFF	AV1 (requires meson + ninja)

Testing

# Run smoke test
./build/tests/build_smoke_test

# Run all tests via CTest
cd build && ctest --output-on-failure

Project Structure

iora_codecs/
  include/iora/codecs/
    core/           MediaBuffer, MediaBufferPool, MediaClock
    format/         SampleFormat, PixelFormat
    codec/          ICodec, ICodecFactory, CodecRegistry, CodecInfo
    dsp/            Resampler, AudioMixer, Gain, VAD, ToneGenerator, Goertzel, WAV
    pipeline/       IMediaHandler, TranscodingHandler, AudioMixerHandler, MediaPipeline
  src/              Implementation files
  modules/          Registry and codec plugins (registry, opus, g711, g722, ilbc, amr, g729, h264, vpx, av1)
  tests/            Unit and integration tests
  libs/             Third-party submodules
  docs/             Architecture document and programmer's manual

Quick Start

#include <iora/iora.hpp>
#include <iora/codecs/codec/codec_registry.hpp>

// Initialize Iora and load plugins
auto& svc = iora::IoraService::instanceRef();
svc.loadSingleModule("mod_codec_registry.so");  // load registry first
svc.loadSingleModule("mod_opus.so");      // auto-registers with registry
svc.loadSingleModule("mod_g711.so");      // auto-registers PCMU + PCMA

// Create codecs via the registry
auto& registry = svc.callExportedApi<iora::codecs::CodecRegistry&>("codecs.registry");
auto opusInfo = registry.findByName("opus");
auto encoder = registry.createEncoder(*opusInfo);
auto decoder = registry.createDecoder(*opusInfo);

See the Programmer's Manual for pipeline construction, DSP processing, and integration patterns.

Documentation

• Programmer's Manual -- complete API reference with integration patterns
• Architecture -- design document with layer descriptions and data flows
• Dependency Guide -- submodule integration details

License

This project is licensed under the Mozilla Public License 2.0.

Third-party dependencies use permissive licenses (BSD-2-Clause, BSD-3-Clause, Apache-2.0). mod_g729.so uses bcg729 (GPL-3.0) — GPL confined to that module only via RTLD_LOCAL. See NOTICE for full attribution.