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AudioContext

The AudioContext interface represents an audio-processing graph built from audio modules linked together, each represented by an AudioNode.

An audio context controls both the creation of the nodes it contains and the execution of the audio processing, or decoding. You need to create an AudioContext before you do anything else, as everything happens inside a context. It's recommended to create one AudioContext and reuse it instead of initializing a new one each time, and it's OK to use a single AudioContext for several different audio sources and pipeline concurrently.

Constructor

AudioContext(): Creates and returns a new AudioContext object.

Instance properties

Also inherits properties from its parent interface, BaseAudioContext.

AudioContext.baseLatency Read only: Returns the number of seconds of processing latency incurred by the AudioContext passing the audio from the AudioDestinationNode to the audio subsystem.
AudioContext.outputLatency Read only: Returns an estimation of the output latency of the current audio context.
AudioContext.sinkId Read only Experimental: Returns the sink ID of the current output audio device.

Instance methods

Also inherits methods from its parent interface, BaseAudioContext.

AudioContext.close(): Closes the audio context, releasing any system audio resources that it uses.
AudioContext.createMediaElementSource(): Creates a MediaElementAudioSourceNode associated with an HTMLMediaElement. This can be used to play and manipulate audio from <video> or <audio> elements.
AudioContext.createMediaStreamSource(): Creates a MediaStreamAudioSourceNode associated with a MediaStream representing an audio stream which may come from the local computer microphone or other sources.
AudioContext.createMediaStreamDestination(): Creates a MediaStreamAudioDestinationNode associated with a MediaStream representing an audio stream which may be stored in a local file or sent to another computer.
AudioContext.createMediaStreamTrackSource(): Creates a MediaStreamTrackAudioSourceNode associated with a MediaStream representing an media stream track.
AudioContext.getOutputTimestamp(): Returns a new AudioTimestamp object containing two audio timestamp values relating to the current audio context.
AudioContext.resume(): Resumes the progression of time in an audio context that has previously been suspended/paused.
AudioContext.setSinkId() Experimental: Sets the output audio device for the AudioContext.
AudioContext.suspend(): Suspends the progression of time in the audio context, temporarily halting audio hardware access and reducing CPU/battery usage in the process.

Events

sinkchange Experimental: Fired when the output audio device (and therefore, the AudioContext.sinkId) has changed.

Examples

Basic audio context declaration:

const audioCtx = new AudioContext();

const oscillatorNode = audioCtx.createOscillator();
const gainNode = audioCtx.createGain();
const finish = audioCtx.destination;
// etc.

Specifications

Specification
Web Audio API # AudioContext

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`AudioContext`	35 ["Before Chrome 66, each tab is limited to 6 audio contexts in Chrome; attempting to create more will throw a `DOMException`. For details see Per-tab audio context limitation in Chrome.", "If `latencyHint` isn't valid, Chrome throws a `TypeError` exception. See Non-standard exceptions in Chrome for details."] 14–57	12	25	No	22 ["Before Opera 53, each tab is limited to 6 audio contexts in Opera; attempting to create more will throw a `DOMException`. For details see Per-tab audio context limitation in Chrome.", "If `latencyHint` isn't valid, Opera throws a `TypeError` exception. See Non-standard exceptions in Chrome for details."] 15–44	14.16	37 ["Before WebView 66, each tab is limited to 6 audio contexts in WebView; attempting to create more will throw a `DOMException`. For details see Per-tab audio context limitation in Chrome.", "If `latencyHint` isn't valid, WebView throws a `TypeError` exception. See Non-standard exceptions in Chrome for details."] ≤37–57	35 ["Before Chrome 66, each tab is limited to 6 audio contexts in Chrome; attempting to create more will throw a `DOMException`. For details see Per-tab audio context limitation in Chrome.", "If `latencyHint` isn't valid, Chrome throws a `TypeError` exception. See Non-standard exceptions in Chrome for details."] 18–57	25	22 ["Before Opera Android 47, each tab is limited to 6 audio contexts in Opera; attempting to create more will throw a `DOMException`. For details see Per-tab audio context limitation in Chrome.", "If `latencyHint` isn't valid, Opera throws a `TypeError` exception. See Non-standard exceptions in Chrome for details."] 14–43	14.56	3.0 ["Before Samsung Internet 9.0, each tab is limited to 6 audio contexts in Samsung Internet; attempting to create more will throw a `DOMException`. For details see Per-tab audio context limitation in Chrome.", "If `latencyHint` isn't valid, Samsung Internet throws a `TypeError` exception. See Non-standard exceptions in Chrome for details."] 1.0–7.0
`AudioContext`	3514–57	12	25	No	2215–44	14.16–14.1	374.4–57	3518–57	25	2214–43	14.56–14.5	3.01.0–7.0
`baseLatency`	58	79	70	No	45	14.1	58	58	79	43	14.5	7.0
`close`	42	14	40	No	29	9	42	42	40	29	9	4.0
`createMediaElementSource`	15	12	25	No	15	6	≤37	18	25	14	6	1.0
`createMediaStreamDestination`	25	79	25	No	15	11	≤37	25	25	14	11	1.5
`createMediaStreamSource`	22	12	25	No	15	11	≤37	25	25	14	11	1.5
`createMediaStreamTrackSource`	No	No	68 Firefox 68 implements the updated standard's definition of the "first" audio track; now the first track is the one whose ID comes first lexicographically.	No	No	No	No	No	68 Firefox 68 implements the updated standard's definition of the "first" audio track; now the first track is the one whose ID comes first lexicographically.	No	No	No
`getOutputTimestamp`	57	79	70	No	44	14.1	57	57	79	43	14.5	7.0
`outputLatency`	102	102	70	No	88	No	102	102	79	70	No	19.0
`resume`	41	14	40	No	28	9	41	41	40	28	9	4.0
`setSinkId`	110	110	No	No	96	No	110	110	No	74	No	21.0
`sinkId`	110	110	No	No	96	No	110	110	No	74	No	21.0
`sinkchange_event`	110	110	No	No	96	No	110	110	No	74	No	21.0
`suspend`	41	14	40	No	28	9	41	41	40	28	9	4.0