librespot-org/librespot
Librespot
librespot is an open-source audio streaming client and library used to implement custom music players that authenticate and stream audio from the Spotify service. It functions as a framework for fetching, decoding, and routing remote audio streams to various system backends and audio sinks.
The project specifically implements a Spotify Connect receiver, allowing it to act as a remote-controllable playback endpoint that appears as a selectable device within other Spotify applications. This enables the creation of virtual playback devices, headless music playback on remote servers, and the integration of streaming into embedded hardware.
The library covers a wide range of audio capabilities, including digital signal processing for dithering and volume normalization, as well as pluggable audio routing for different operating system sound servers. It handles network device discovery to locate playback targets on a local area network and manages secure communication through system-native TLS integration.
User identity is managed through interactive browser-based authentication flows and token-based access control, while local caching is used to store audio data and credentials to reduce network latency.
Features
- Remote Playback Receivers - Implements a virtual playback endpoint that accepts external control commands to manage music streaming.
- Spotify Client Libraries - Provides a comprehensive library for building custom applications that authenticate and stream from Spotify.
- Audio Hardware Routing - Directs audio streams to various system sound servers and hardware outputs for cross-platform playback.
- Audio Streaming Engines - Functions as an engine for fetching, decoding, and routing remote audio streams to system backends.
- Audio Playback Engines - Provides the engine required to play remote audio streams through various system backends.
- Cross-Platform Audio Engines - Utilizes platform-specific audio engines to support various architectures and minimize latency.
- Streaming Clients - Implements the client-side logic necessary to fetch and consume audio streams from a remote music service.
- Remote Playback Targets - Implements the ability to register as a remote target for discovery and control by other music clients.
- Spotify Connect Implementations - Implements the Spotify Connect protocol to function as a remote-controllable playback device.
- User Identity Verification - Verifies user identities via interactive browser flows and third-party provider tokens.
- Token-Based Authentication - Verifies user identity through interactive browser flows and manages scoped access tokens.
- Virtual Device Endpoints - Implements a virtual playback device that functions as a software-only logical endpoint for remote control.
- Local State Caches - Persists encrypted audio data and authentication credentials locally to reduce network latency and maintain sessions.
- Audio Mixing - Controls playback volume through software-based mixing or direct hardware integration.
- Audio Processing - Provides real-time sound manipulation by routing audio through custom processing pipelines.
- Processing Pipelines - Implements a sequence of modification stages for audio normalization, dithering, and gain adjustment.
- Music Source Integrations - Integrates a remote music service to enable streaming playback via various system backends.
- Headless Playback Clients - Supports running a streaming service on a remote server as a background process without a GUI.
- Audio Output Configurations - Configures audio output bit-depth and formats to balance playback quality and performance.
- Audio Volume Controls - Adjusts audio levels using stream-provided gain values to ensure consistent loudness.
- Media Playback Controls - Provides standard APIs for managing playback states such as play, pause, and track skipping.
- Embedded Audio Streaming - Enables the integration of music streaming into low-power hardware or custom embedded operating systems.
- Device Instance Registrations - Registers a device instance for discovery so remote music applications can find and control playback.
- Local Network Discovery - Uses standard network discovery protocols to locate compatible hardware on the local wireless network.
- Network Device Discovery - Uses network protocols to automatically identify and register compatible playback targets on a local area network.
- Audio Output Pipelines - Provides an architecture for routing processed audio streams to various software or hardware output drivers.
- Music Streaming - Open-source client library for Spotify.
