Audio engine #

This component is responsible for playing audio in the browser or web view. This component does not depend on any Diffuse-specific data structures.

Requirements #

It should be able to play audio from a URL to a binary audio file, or an audio stream.
When given an URL, it should not load the entire audio file into memory.
Seeking should be enabled if possible (obviously not feasible for live streams).
The element should operate in broadcast mode when a group attribute is present.
Broadcasting the audio element allows other browser tabs to monitor its playback progress and state, volume, etc.
When the broadcast leader tab gets closed, another tab will take the leader role and when that happens; if the audio was playing, the audio must start playing in the tab of the new leader.
Consumers of this custom element must be able to tap into the code that allows for audio visualisations. Though it is not required to work simultaneously on all browser tabs.
Audio is routed through the Web Audio API (createMediaElementSource) so consumers can insert their own processing (equalizer filters, analyzers for visualizations, etc) via the exposed webAudio graph.
The volume of the audio must be able to be set and persisted across sessions. This value depends on the used group.
The audio output device must be able to be selected and persisted across sessions. This value depends on the used group.
The mime type must be set on the audio if provided.
The element must support a initial-progress attribute which can be used to start playing audio from that particular point.
Audio must be able to preloaded in the background.

When using a HTML audio element, use a silent audio file data-uri as the src to cancel the loading of any data.