AudioScheduledSourceNode: start() method

The start() method on AudioScheduledSourceNode schedules a sound to begin playback at the specified time. If no time is specified, then the sound begins playing immediately.

Syntax

start()
start(when)

Parameters

when Optional

The time, in seconds, at which the sound should begin to play. This value is specified in the same time coordinate system as the AudioContext is using for its currentTime attribute. A value of 0 (or omitting the when parameter entirely) causes the sound to start playback immediately.

Return value

None (undefined).

Exceptions

InvalidStateNode DOMException

Thrown if the node has already been started. This error occurs even if the node is no longer running because of a prior call to stop().

RangeError

Thrown if the value specified for when is negative.

Examples

This example demonstrates how to create an OscillatorNode which is scheduled to start playing in 2 seconds and stop playing 1 second after that. The times are calculated by adding the desired number of seconds to the context's current time stamp returned by AudioContext.currentTime.

context = new AudioContext();
osc = context.createOscillator();
osc.connect(context.destination);

/* Schedule the start and stop times for the oscillator */

osc.start(context.currentTime + 2);
osc.stop(context.currentTime + 3);

Specifications

Browser compatibility

See also

• Using the Web Audio API
• stop()
• AudioScheduledSourceNode
• AudioBufferSourceNode
• ConstantSourceNode
• OscillatorNode