AudioParam: linearRampToValueAtTime() method
The linearRampToValueAtTime()
method of the AudioParam
Interface schedules a gradual linear change in the value of the
AudioParam
. The change starts at the time specified for the
previous event, follows a linear ramp to the new value given in the
value
parameter, and reaches the new value at the time given in the
endTime
parameter.
Syntax
js
linearRampToValueAtTime(value, endTime)
Parameters
value
-
A floating point number representing the value the
AudioParam
will ramp to by the given time. endTime
-
A double representing the exact time (in seconds) after the ramping starts that the changing of the value will stop.
Return value
A reference to this AudioParam
object. In some browsers older
implementations of this interface return undefined
.
Examples
In this example, we have a media source with two control buttons (see the audio-param repo for the source code, or view the example live.) When these buttons are pressed, linearRampToValueAtTime()
is
used to fade the gain value up to 1.0, and down to 0, respectively. This is pretty
useful for fade in/fade out effects, although AudioParam.exponentialRampToValueAtTime()
is often said to be a bit more
natural.
js
// create audio context
const audioCtx = new AudioContext();
// set basic variables for example
const myAudio = document.querySelector("audio");
const linearRampPlus = document.querySelector(".linear-ramp-plus");
const linearRampMinus = document.querySelector(".linear-ramp-minus");
// Create a MediaElementAudioSourceNode
// Feed the HTMLMediaElement into it
const source = audioCtx.createMediaElementSource(myAudio);
// Create a gain node and set it's gain value to 0.5
const gainNode = audioCtx.createGain();
// connect the AudioBufferSourceNode to the gainNode
// and the gainNode to the destination
gainNode.gain.setValueAtTime(0, audioCtx.currentTime);
source.connect(gainNode);
gainNode.connect(audioCtx.destination);
// set buttons to do something onclick
linearRampPlus.onclick = () => {
gainNode.gain.linearRampToValueAtTime(1.0, audioCtx.currentTime + 2);
};
linearRampMinus.onclick = () => {
gainNode.gain.linearRampToValueAtTime(0, audioCtx.currentTime + 2);
};
Specifications
Specification |
---|
Web Audio API # dom-audioparam-linearramptovalueattime |
Browser compatibility
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