AudioBuffer: numberOfChannels property

The numberOfChannels property of the AudioBuffer interface returns an integer representing the number of discrete audio channels described by the PCM data stored in the buffer.

Value

An integer.

Examples

// Stereo
const channels = 2;

// Create an empty two second stereo buffer at the
// sample rate of the AudioContext
const frameCount = audioCtx.sampleRate * 2.0;
const myArrayBuffer = audioCtx.createBuffer(2, frameCount, audioCtx.sampleRate);

button.onclick = () => {
  // Fill the buffer with white noise;
  // just random values between -1.0 and 1.0
  for (let channel = 0; channel < channels; channel++) {
    // This gives us the actual ArrayBuffer that contains the data
    const nowBuffering = myArrayBuffer.getChannelData(channel);
    for (let i = 0; i < frameCount; i++) {
      // Math.random() is in [0; 1.0]
      // audio needs to be in [-1.0; 1.0]
      nowBuffering[i] = Math.random() * 2 - 1;
    }
  }

  console.log(myArrayBuffer.numberOfChannels);
};

Specifications

Browser compatibility

See also

• Using the Web Audio API