Playback and audio

Minimal controls

Load a Project, attach preview, then use session.player.play(), pause(), and seek(timeUs). Reflect the Player snapshot in UI rather than assuming a click immediately changed state.

Player state

Track ready/playing/paused/seeking/ended/error, current timeline time, rate, buffering/stall data, audio transport, and the diagnostic that caused a terminal error.

Seek, scrub, and render

Seek changes playback position. Scrubbing is a product interaction that may pause, request many preview frames, and seek once at completion. preview.render() alone does not move the audio clock.

Audio as master clock

When audio is active, AudioWorklet timing is the authority and video is scheduled against it. Falling behind may drop an obsolete video frame; stretching the timeline interpretation to preserve every visual frame would create A/V drift.

Browser gesture restrictions

Create/resume audio in response to a user gesture and surface a clear “enable audio” state when the browser blocks it. Do not hide autoplay rejection as a generic playback failure.

Transport mode

Cross-origin isolation enables the preferred shared-memory path. Without it, Aelion uses a bounded transferable fallback where supported. Capability reports expose the active mode so products can set expectations.

Preview quality and edits

Set a playback-appropriate preview quality. If a commit occurs during playback, consume the new revision through the documented Player/Session transition; do not let a UI store combine an old audio graph with a new visual snapshot.

Monitoring and disposal

Watch underruns, queue depth, dropped video frames, clock drift, decode/render latency, and PLAYER_RUNTIME_FAILED. Stop and dispose the Player before disposing the Session and media owner.