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Features

Sezo Audio Engine ships as two packages: an Android package for native apps and an Expo module for cross-platform apps with a full iOS implementation and background playback.

Feature Highlights

  • Low-latency, multi-track playback with sample-accurate sync
  • Pitch and speed control
  • Recording and extraction
  • Background playback (Expo module)
  • Cross-platform JS/TS API with Android and iOS parity

Core Concepts

Timing and Units

  • Sample rate: number of audio samples per second (e.g., 44100 Hz).
  • Frame: one sample per channel. Stereo audio has 2 samples per frame.
  • Position: the engine reports playback position in milliseconds.

Tracks

Each track is identified by a string id and has a source file path/URI. Tracks can have a start offset (startTimeMs) to align material on the timeline.

Synchronization

All tracks share a master clock. Timing conversions are handled internally so playback stays sample-accurate across tracks.

File Formats

Input formats: - MP3 - WAV

Recording/export formats: - AAC (Android MediaCodec) - MP3 (optional LAME) - WAV (lossless)

Threading

Audio processing runs on a real-time audio thread. Keep heavy work off the callback and update parameters from a separate thread/UI layer.