VideoFrame: VideoFrame() constructor

The first type of constructor (see above) creates a new VideoFrame from an image. Its parameters are:

image

An image containing the image data for the new VideoFrame. It can be one of the following objects: an SVGImageElement, an HTMLVideoElement, an HTMLCanvasElement, an ImageBitmap, an OffscreenCanvas, or another VideoFrame.

options Optional

An object containing the following:

duration Optional

An integer representing the duration of the frame in microseconds.

timestamp

An integer representing the timestamp of the frame in microseconds.

alpha Optional

A string, describing how the user agent should behave when dealing with alpha channels. The default value is "keep".

• "keep": Indicates that the user agent should preserve alpha channel data.
• "discard": Indicates that the user agent should ignore or remove alpha channel data.

visibleRect Optional

An object representing the visible rectangle of the VideoFrame, containing the following:

x

The x-coordinate.

y

The y-coordinate.

width

The width of the frame.

height

The height of the frame.

displayWidth Optional

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

displayHeight Optional

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

The second type of constructor (see above) creates a new VideoFrame from an ArrayBuffer. Its parameters are:

data

An ArrayBuffer, a TypedArray, or a DataView containing the data for the new VideoFrame.

options

An object containing the following:

format

A string representing the video pixel format. One of the following strings, which are fully described on the page for the format property:

• "I420"
• "I420A"
• "I422"
• "I444"
• "NV12"
• "RGBA"
• "RGBX"
• "BGRA"
• "BGRX"

codedWidth

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

codedHeight

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

timestamp

An integer representing the timestamp of the frame in microseconds.

duration Optional

An integer representing the duration of the frame in microseconds.

layout Optional

A list containing the following values for each plane in the VideoFrame:

offset

An integer representing the offset in bytes where the given plane begins.

stride

An integer representing the number of bytes, including padding, used by each row of the plane. Planes may not overlap. If no layout is specified, the planes will be tightly packed.

visibleRect Optional

An object representing the visible rectangle of the VideoFrame, containing the following:

x

The x-coordinate.

y

The y-coordinate.

width

The width of the frame.

height

The height of the frame.

displayWidth Optional

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

displayHeight Optional

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

colorSpace

An object representing the color space of the VideoFrame, containing the following:

primaries

A string representing the video color primaries, described on the page for the VideoColorSpace.primaries property.

transfer

A string representing the video color transfer function, described on the page for the VideoColorSpace.transfer property.

matrix

A string representing the video color matrix, described on the page for the VideoColorSpace.matrix property.

fullRange

A Boolean. If true, indicates that full-range color values are used.

transfer

An array of ArrayBuffers that VideoFrame will detach and take ownership of. If the array contains the ArrayBuffer backing data, VideoFrame will use that buffer directly instead of copying from it.

The following examples are from the article Video processing with WebCodecs. In this first example, a VideoFrame is created from a canvas.

const cnv = document.createElement("canvas");
// draw something on the canvas
// ...
let frame_from_canvas = new VideoFrame(cnv, { timestamp: 0 });

In the following example a VideoFrame is created from a TypedArray.

const pixelSize = 4;
let init = {
  timestamp: 0,
  codedWidth: 320,
  codedHeight: 200,
  format: "RGBA",
};
let data = new Uint8Array(init.codedWidth * init.codedHeight * pixelSize);
for (let x = 0; x < init.codedWidth; x++) {
  for (let y = 0; y < init.codedHeight; y++) {
    let offset = (y * init.codedWidth + x) * pixelSize;
    data[offset] = 0x7f; // Red
    data[offset + 1] = 0xff; // Green
    data[offset + 2] = 0xd4; // Blue
    data[offset + 3] = 0x0ff; // Alpha
  }
}
init.transfer = [data.buffer];
let frame = new VideoFrame(data, init);