getAudioTrackList method

Description

Returns the list of available "audio tracks" for the currently loaded content.

Audio tracks group one or more renditions sharing the same characteristics: language, accessibility role, etc. Multiple renditions may exist under one track when, for example, several audio quality levels are available.

These correspond to distinctly selectable tracks, not just to the presence of audio samples in the content: muxed media playlists containing video and audio combined will generally not be exposed as a separate audio track.

This method will return an array of objects, each object containing the information available for a particular audio track.

Each of those objects should contain the following keys (same than for the audioTrackListUpdate event):

• id (number): The identifier for that audio track. It is generally useful to for example set the audio track though a setAudioTrack call.

• language (string | undefined): The primary language used in this audio track, as a language tag.

  undefined if unknown or if there's no language involved.

• assocLanguage (string | undefined): A secondary language associated with the audio track, as a language tag. Such language is often used in a different role than the language specified through the language property (e.g., written versus spoken, or a fallback dialect).

  undefined if unknown or if there's no language involved.

• name (string): Human-readable description of the audio track. If the language property is set, it should generally be in that language.

• channels (number | undefined): If set, it is the count of audio channels, indicating the maximum number of independent and simultaneous audio channels present in any media data in that audio track.

  For example, an AC-3 5.1 Rendition would have a channels attribute set to 6.

• characteristics (Array.<string> | undefined): Semantic characteristics linked to that audio track, generally expressed as Uniform Type Identifiers such as accessibility-related metadata or commentary flags.

  undefined if unknown or if no such characteristics are announced.

• bitDepth (number | undefined): If set, the bit depth in bits of the audio samples for every rendition grouped into that audio track.

  undefined if unknown or if grouped renditions do not all share the same bit depth.

• sampleRate (number | undefined): If set, the sample rate in hertz of the audio samples for every rendition grouped into that audio track.

  undefined if unknown or if grouped renditions do not all share the same sample rate.

• bitDepths (Array.<number> | undefined): Distinct bit depths in bits found among the renditions grouped into that audio track.

• sampleRates (Array.<number> | undefined): Distinct sample rates in hertz found among the renditions grouped into that audio track.

That list of audio tracks is known once the audioTrackListUpdate event is sent for the currently-loaded content, which should happen at least once before the content is in the "Loaded" state (and thus before playback starts).

If no content is currently loaded or if there is but audio tracks characteristics are either inexistant or unknown, this method will return an empty array ([]).

Syntax

const audioTracks = player.getAudioTrackList();

• return value:

Array.<Object>: Characteristics of the currently available audio tracks (see previous chapter). Empty if no content is loaded, if there's no audio tracks in the loaded content or if its characteristics are unknown.