VideoFrame

Description

A VideoFrame object can be created or accessed in a number of ways. The MediaStreamTrackProcessor breaks a media track into individual VideoFrame objects.

A VideoFrame is an image source and has a constructor that accepts any other canvas source ( an SVGImageElement, an HTMLVideoElement, an HTMLCanvasElement, an ImageBitmap, an OffscreenCanvas, or another VideoFrame). This means that a frame can be created from an image or video element.

A second constructor enables the creation of a VideoFrame from its binary pixel representation in an ArrayBuffer, a TypedArray, or a DataView.

Created frames may then turned into a media track, for example with the MediaStreamTrackGenerator interface that creates a media track from a stream of frames.

Constructor

VideoFrame()

Creates a new VideoFrame object.

Instance properties

VideoFrame.format Read only

Returns the pixel format of the VideoFrame.

VideoFrame.codedWidth Read only

Returns the width of the VideoFrame in pixels, potentially including non-visible padding, and prior to considering potential ratio adjustments.

VideoFrame.codedHeight Read only

Returns the height of the VideoFrame in pixels, potentially including non-visible padding, and prior to considering potential ratio adjustments.

VideoFrame.codedRect Read only

Returns a DOMRectReadOnly with the width and height matching codedWidth and codedHeight.

VideoFrame.visibleRect Read only

Returns a DOMRectReadOnly describing the visible rectangle of pixels for this VideoFrame.

VideoFrame.displayWidth Read only

Returns the width of the VideoFrame when displayed after applying aspect ratio adjustments.

VideoFrame.displayHeight Read only

Returns the height of the VideoFrame when displayed after applying aspect ratio adjustments.

VideoFrame.duration Read only

Returns an integer indicating the duration of the video in microseconds.

VideoFrame.timestamp Read only

Returns an integer indicating the timestamp of the video in microseconds.

VideoFrame.colorSpace Read only

Returns a VideoColorSpace object.

VideoFrame.flip Read only

Returns whether the VideoFrame is horizontally mirrored.

VideoFrame.rotation Read only

Returns the rotation (0, 90, 180, or 270) in degrees clockwise applied to the VideoFrame. Arbitrary numbers (including negatives) are rounded to the next quarter turn.

Instance methods

VideoFrame.allocationSize()

Returns the number of bytes required to hold the VideoFrame as filtered by options passed into the method.

VideoFrame.copyTo()

Copies the contents of the VideoFrame to an ArrayBuffer.

VideoFrame.clone()

Creates a new VideoFrame object with reference to the same media resource as the original.

VideoFrame.close()

Clears all states and releases the reference to the media resource.

Examples

In the following example frames are returned from a MediaStreamTrackProcessor, then encoded. See the full example and read more about it in the article Video processing with WebCodecs.

let frameCounter = 0;

const track = stream.getVideoTracks()[0];
const mediaProcessor = new MediaStreamTrackProcessor(track);

const reader = mediaProcessor.readable.getReader();
while (true) {
  const result = await reader.read();
  if (result.done) break;

  let frame = result.value;
  if (encoder.encodeQueueSize > 2) {
    // Too many frames in flight, encoder is overwhelmed
    // let's drop this frame.
    frame.close();
  } else {
    frameCounter++;
    const insertKeyframe = frameCounter % 150 === 0;
    encoder.encode(frame, { keyFrame: insertKeyframe });
    frame.close();
  }
}

Specifications

Browser compatibility

See also

• Video processing with WebCodecs
• WebCodecs examples