Function InitializeFrameFromOtherFrame

src/video_frame.ts:882–942

(
	init: VideoFrameInit,
	frame: VideoFramePolyfill,
	otherFrame: VideoFramePolyfill,
)

};

const InitializeFrameFromOtherFrame = (
	init: VideoFrameInit,
	frame: VideoFramePolyfill,
	otherFrame: VideoFramePolyfill,
) => {
	// 1. Let format be otherFrame.format.
	let format = otherFrame.format;

	// 2. If init.alpha is discard, assign otherFrame.format’s equivalent opaque format format.
	if (init.alpha === 'discard' && format) {
		format = getEquivalentOpaqueFormat(format) as VideoPixelFormat;
	}

	// 3. Let validInit be the result of running the Validate VideoFrameInit algorithm...
	if (!ValidateVideoFrameInit(init, format, otherFrame.codedWidth, otherFrame.codedHeight)) {
		throw new TypeError('Invalid VideoFrameInit');
	}

	// 4. Let resource be the media resource referenced by otherFrame...
	frame.data = otherFrame.data;

	// 5. Assign the following attributes from otherFrame to frame: codedWidth, codedHeight, colorSpace.
	// @ts-expect-error Write to readonly
	frame.codedWidth = otherFrame.codedWidth;
	// @ts-expect-error Write to readonly
	frame.codedHeight = otherFrame.codedHeight;
	// @ts-expect-error Write to readonly
	frame.colorSpace = new VideoColorSpacePolyfill(otherFrame.colorSpace);

	// 6. Let defaultVisibleRect be the result of performing the getter steps for visibleRect on otherFrame.
	const defaultVisibleRect = otherFrame.visibleRect!;

	// 7. Let baseRotation and baseFlip be otherFrame’s [[rotation]] and [[flip]].
	const baseRotation = otherFrame.rotation;
	const baseFlip = otherFrame.flip;

	// 8. Let defaultDisplayWidth and defaultDisplayHeight...
	const defaultDisplayWidth = otherFrame.displayWidth;
	const defaultDisplayHeight = otherFrame.displayHeight;

	// 9. Run the Initialize Visible Rect, Orientation, and Display Size algorithm.
	InitializeVisibleRectOrientationAndDisplaySize(
		init, frame, defaultVisibleRect, baseRotation, baseFlip, defaultDisplayWidth, defaultDisplayHeight,
	);

	// 10. If duration exists in init...
	// @ts-expect-error Write to readonly
	frame.duration = init.duration != null
		? Math.trunc(init.duration)
		: otherFrame.duration;

	// 11. If timestamp exists in init...
	// @ts-expect-error Write to readonly
	frame.timestamp = init.timestamp != null
		? Math.trunc(init.timestamp)
		: otherFrame.timestamp;

	// 12. Assign format to frame.[[format]].