# xiph/opus

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3,035 stars · 746 forks · C · other

## Links

- GitHub: https://github.com/xiph/opus
- Homepage: https://opus-codec.org/
- awesome-repositories: https://awesome-repositories.com/repository/xiph-opus.md

## Topics

`audio` `c` `codec` `compression`

## Description

Opus is a lossy audio compression standard and codec designed for high-quality speech and music transmission over the internet. It functions as a low-latency audio codec and network-resilient streamer, providing a framework for encoding and decoding digital audio.

The project distinguishes itself through the support of multi-channel ambisonics for immersive three-dimensional spatial audio reproduction. It is specifically optimized for real-time interactive communication, utilizing dynamic bitrate adjustment and forward error correction to maintain audio quality on unstable networks.

The system covers a broad range of audio processing capabilities, including high-fidelity encoding with support for high sampling rates and bit depths. It also provides tools for bandwidth extension, audio file management, and web audio integration for browser-based playback.

The implementation includes support for embedded audio processing on low-power hardware via integer-based fixed-point arithmetic.

## Tags

### Part of an Awesome List

- [Audio Codecs](https://awesome-repositories.com/f/awesome-lists/media/audio-codecs.md) — Provides a high-quality audio codec that dynamically switches between speech and music-centric cores for optimal compression.
- [Adaptive Bitrate Optimization](https://awesome-repositories.com/f/awesome-lists/media/video-transmission/adaptive-bitrate-optimization.md) — Dynamically adjusts audio bandwidth and bitrate in real-time to match network conditions and prevent audible glitches. ([source](https://opus-codec.org/examples))

### Graphics & Multimedia

- [Audio Codec Decoders](https://awesome-repositories.com/f/graphics-multimedia/audio-codec-decoders.md) — Translates compressed bitstreams back into raw audio for playback or further processing. ([source](https://opus-codec.org/development))
- [Audio Codecs](https://awesome-repositories.com/f/graphics-multimedia/audio-codecs.md) — Compresses and decompresses audio streams for interactive speech and music transmission using a high-quality open standard. ([source](https://cdn.jsdelivr.net/gh/xiph/opus@main/README.md))
- [Immersive Audio Processors](https://awesome-repositories.com/f/graphics-multimedia/audio-music/audio-processing/immersive-audio-processors.md) — Processes high-order ambisonics to enable multi-channel immersive audio experiences. ([source](https://opus-codec.org/feed.xml))
- [Stream Decoding](https://awesome-repositories.com/f/graphics-multimedia/audio-music/audio-processing/stream-decoding.md) — Converts compressed audio formats back into raw PCM data for playback or processing. ([source](https://opus-codec.org/release/stable/2026/01/14/libopus-1_6_1.html))
- [Spatial Audio](https://awesome-repositories.com/f/graphics-multimedia/audio-music/spatial-audio.md) — Processing multi-channel high-order ambisonics to create three-dimensional sound experiences for listeners.
- [Audio Stream Compression](https://awesome-repositories.com/f/graphics-multimedia/audio-stream-compression.md) — Compresses raw audio data into efficient digital formats to optimize network bandwidth for transmission. ([source](https://opus-codec.org/release/stable/2026/01/14/libopus-1_6_1.html))
- [Discrete Cosine Transforms](https://awesome-repositories.com/f/graphics-multimedia/discrete-cosine-transforms.md) — Converts time-domain audio into frequency-domain coefficients to remove perceptually redundant data for higher compression ratios.
- [Hybrid Audio Codecs](https://awesome-repositories.com/f/graphics-multimedia/hybrid-audio-codecs.md) — Combines speech-specific linear prediction with transform-based encoding to efficiently handle both voice and music in a single stream.
- [Network-Resilient Audio Streaming](https://awesome-repositories.com/f/graphics-multimedia/network-resilient-audio-streaming.md) — Implements forward error correction and packet loss concealment to maintain audio quality on unstable networks.
- [Psychoacoustic Models](https://awesome-repositories.com/f/graphics-multimedia/psychoacoustic-models.md) — Reduces the precision of frequency coefficients based on human hearing thresholds to minimize perceived distortion.
- [Ambisonic Audio Mapping](https://awesome-repositories.com/f/graphics-multimedia/ambisonic-audio-mapping.md) — Encodes spatial audio by decomposing sound fields into spherical harmonics for immersive three-dimensional playback.
- [Audio Bandwidth Extension](https://awesome-repositories.com/f/graphics-multimedia/audio-bandwidth-extension.md) — Upsamples wideband audio to fullband frequencies using a bandwidth extension module to improve high-frequency clarity. ([source](https://opus-codec.org/feed.xml))
- [High Bit Depth Processing](https://awesome-repositories.com/f/graphics-multimedia/audio-music/audio-processing/high-bit-depth-processing.md) — Encodes and decodes audio using 24-bit precision to preserve a wider dynamic range. ([source](https://opus-codec.org/release/stable/2025/12/15/libopus-1_6.html))
- [High Resolution](https://awesome-repositories.com/f/graphics-multimedia/audio-music/audio-processing/high-resolution.md) — Handles audio sampling rates up to 96 kHz to maintain high fidelity for professional-grade audio content. ([source](https://opus-codec.org/release/stable/2025/12/15/libopus-1_6.html))
- [Integer](https://awesome-repositories.com/f/graphics-multimedia/audio-music/audio-processing/integer.md) — Encodes and decodes audio using a 24-bit integer format to maintain dynamic range without floating-point arithmetic. ([source](https://opus-codec.org/demo/opus-1.6/))
- [Web Audio Libraries](https://awesome-repositories.com/f/graphics-multimedia/audio-music/web-audio-libraries.md) — Formatting compressed audio streams for browser-based playback to ensure compatibility across different web players.
- [High Fidelity Audio Encoding](https://awesome-repositories.com/f/graphics-multimedia/high-fidelity-audio-encoding.md) — Captures professional-grade audio with high sampling rates and bit depth to preserve wide dynamic range and clarity.
- [High-Resolution Audio Encoding](https://awesome-repositories.com/f/graphics-multimedia/high-resolution-audio-encoding.md) — Captures ultrasonic frequencies and increases quantizer resolution by supporting high sampling rates and bitrates. ([source](https://opus-codec.org/demo/opus-1.6/))
- [Neural Speech Bandwidth Extension](https://awesome-repositories.com/f/graphics-multimedia/neural-speech-bandwidth-extension.md) — Synthesizes high-frequency content from wideband speech using a neural network to produce fullband audio. ([source](https://opus-codec.org/demo/opus-1.6/))
- [Spectral Bandwidth Extension](https://awesome-repositories.com/f/graphics-multimedia/spectral-bandwidth-extension.md) — Synthesizes high-frequency content from a lower-bandwidth signal to reconstruct a full-range audio spectrum.
- [Spherical Harmonic Audio Encoding](https://awesome-repositories.com/f/graphics-multimedia/spherical-harmonic-audio-encoding.md) — Encodes spatial audio by decomposing sound fields into coefficients for immersive three-dimensional playback.

### Hardware & IoT

- [Embedded Audio Streaming](https://awesome-repositories.com/f/hardware-iot/embedded-audio-streaming.md) — Runs high-quality audio encoding and decoding on low-power hardware using integer-based fixed-point arithmetic.

### Networking & Communication

- [Adaptive Bitrate Controllers](https://awesome-repositories.com/f/networking-communication/adaptive-bitrate-controllers.md) — Implements systems that dynamically adjust audio stream quality and bitrate based on real-time network congestion metrics.
- [Forward Error Correction](https://awesome-repositories.com/f/networking-communication/forward-error-correction.md) — Embeds redundant data from previous frames into subsequent packets to reconstruct audio lost during network transmission.
- [Low-Latency Audio Coding](https://awesome-repositories.com/f/networking-communication/low-bitrate-audio-coding/low-latency-audio-coding.md) — Provides a compression standard optimized for real-time interactive communication with minimal delay.
- [Packet Loss Concealment](https://awesome-repositories.com/f/networking-communication/packet-loss-concealment.md) — Uses redundancy and concealment techniques to maintain audio playback quality when data packets are lost during transmission. ([source](https://opus-codec.org/feed.xml))
- [Real-time Communication Platforms](https://awesome-repositories.com/f/networking-communication/real-time-communication-platforms.md) — Compressing speech and music for low-latency transmission over the internet with dynamic bitrate adjustment for network stability.
- [Network-Resilient Audio Streaming](https://awesome-repositories.com/f/networking-communication/socket-networking/audio-streaming-servers/pcm-audio-streaming/network-resilient-audio-streaming.md) — Maintaining continuous audio playback during packet loss using redundancy and concealment techniques to prevent audible glitches.

### Artificial Intelligence & ML

- [Neural Audio Reconstruction](https://awesome-repositories.com/f/artificial-intelligence-ml/deep-learning-audio-libraries/neural-audio-reconstruction.md) — Embeds recovery data within packet padding using deep learning to maintain audio quality across lossy networks. ([source](https://cdn.jsdelivr.net/gh/xiph/opus@main/README.md))

### Software Engineering & Architecture

- [Fixed-Point Math Optimizations](https://awesome-repositories.com/f/software-engineering-architecture/integer-arithmetic/fixed-point-math-optimizations.md) — Uses integer and fixed-point arithmetic to replace floating-point operations for optimized performance on low-power embedded hardware.

### Web Development

- [Web Audio Integration](https://awesome-repositories.com/f/web-development/web-audio-integration.md) — Formats audio for web-based players to decode and play back compressed audio files or live streams. ([source](https://opus-codec.org/examples))