mediabunny/src/sample.ts

/*!
 * Copyright (c) 2025-present, Vanilagy and contributors
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

import {
	assert,
	clamp,
	isAllowSharedBufferSource,
	Rotation,
	SECOND_TO_MICROSECOND_FACTOR,
	toDataView,
	toUint8Array,
	SetRequired,
	isFirefox,
	polyfillSymbolDispose,
} from './misc';

polyfillSymbolDispose();

/**
 * Metadata used for VideoSample initialization.
 * @group Samples
 * @public
 */
export type VideoSampleInit = {
	/**
	 * The internal pixel format in which the frame is stored.
	 * [See pixel formats](https://developer.mozilla.org/en-US/docs/Web/API/VideoFrame/format)
	 */
	format?: VideoPixelFormat;
	/** The width of the frame in pixels. */
	codedWidth?: number;
	/** The height of the frame in pixels. */
	codedHeight?: number;
	/** The rotation of the frame in degrees, clockwise. */
	rotation?: Rotation;
	/** The presentation timestamp of the frame in seconds. */
	timestamp?: number;
	/** The duration of the frame in seconds. */
	duration?: number;
	/** The color space of the frame. */
	colorSpace?: VideoColorSpaceInit;
};

/**
 * Represents a raw, unencoded video sample (frame). Mainly used as an expressive wrapper around WebCodecs API's
 * [`VideoFrame`](https://developer.mozilla.org/en-US/docs/Web/API/VideoFrame), but can also be used standalone.
 * @group Samples
 * @public
 */
export class VideoSample implements Disposable {
	/** @internal */
	_data!: VideoFrame | OffscreenCanvas | Uint8Array | null;
	/** @internal */
	_closed: boolean = false;

	/**
	 * The internal pixel format in which the frame is stored.
	 * [See pixel formats](https://developer.mozilla.org/en-US/docs/Web/API/VideoFrame/format)
	 */
	readonly format!: VideoPixelFormat | null;
	/** The width of the frame in pixels. */
	readonly codedWidth!: number;
	/** The height of the frame in pixels. */
	readonly codedHeight!: number;
	/** The rotation of the frame in degrees, clockwise. */
	readonly rotation!: Rotation;
	/**
	 * The presentation timestamp of the frame in seconds. May be negative. Frames with negative end timestamps should
	 * not be presented.
	 */
	readonly timestamp!: number;
	/** The duration of the frame in seconds. */
	readonly duration!: number;
	/** The color space of the frame. */
	readonly colorSpace!: VideoColorSpace;

	/** The width of the frame in pixels after rotation. */
	get displayWidth() {
		return this.rotation % 180 === 0 ? this.codedWidth : this.codedHeight;
	}

	/** The height of the frame in pixels after rotation. */
	get displayHeight() {
		return this.rotation % 180 === 0 ? this.codedHeight : this.codedWidth;
	}

	/** The presentation timestamp of the frame in microseconds. */
	get microsecondTimestamp() {
		return Math.trunc(SECOND_TO_MICROSECOND_FACTOR * this.timestamp);
	}

	/** The duration of the frame in microseconds. */
	get microsecondDuration() {
		return Math.trunc(SECOND_TO_MICROSECOND_FACTOR * this.duration);
	}

	/**
	 * Whether this sample uses a pixel format that can hold transparency data. Note that this doesn't necessarily mean
	 * that the sample is transparent.
	 */
	get hasAlpha() {
		return this.format && this.format.includes('A');
	}

	/**
	 * Creates a new {@link VideoSample} from a
	 * [`VideoFrame`](https://developer.mozilla.org/en-US/docs/Web/API/VideoFrame). This is essentially a near zero-cost
	 * wrapper around `VideoFrame`. The sample's metadata is optionally refined using the data specified in `init`.
	*/
	constructor(data: VideoFrame, init?: VideoSampleInit);
	/**
	 * Creates a new {@link VideoSample} from a
	 * [`CanvasImageSource`](https://udn.realityripple.com/docs/Web/API/CanvasImageSource), similar to the
	 * [`VideoFrame`](https://developer.mozilla.org/en-US/docs/Web/API/VideoFrame) constructor. When `VideoFrame` is
	 * available, this is simply a wrapper around its constructor. If not, it will copy the source's image data to an
	 * internal canvas for later use.
	 */
	constructor(data: CanvasImageSource, init: SetRequired<VideoSampleInit, 'timestamp'>);
	/**
	 * Creates a new {@link VideoSample} from raw pixel data specified in `data`. Additional metadata must be provided
	 * in `init`.
	 */
	constructor(
		data: AllowSharedBufferSource,
		init: SetRequired<VideoSampleInit, 'format' | 'codedWidth' | 'codedHeight' | 'timestamp'>
	);
	constructor(
		data: VideoFrame | CanvasImageSource | AllowSharedBufferSource,
		init?: VideoSampleInit,
	) {
		if (data instanceof ArrayBuffer || ArrayBuffer.isView(data)) {
			if (!init || typeof init !== 'object') {
				throw new TypeError('init must be an object.');
			}
			if (!('format' in init) || typeof init.format !== 'string') {
				throw new TypeError('init.format must be a string.');
			}
			if (!Number.isInteger(init.codedWidth) || init.codedWidth! <= 0) {
				throw new TypeError('init.codedWidth must be a positive integer.');
			}
			if (!Number.isInteger(init.codedHeight) || init.codedHeight! <= 0) {
				throw new TypeError('init.codedHeight must be a positive integer.');
			}
			if (init.rotation !== undefined && ![0, 90, 180, 270].includes(init.rotation)) {
				throw new TypeError('init.rotation, when provided, must be 0, 90, 180, or 270.');
			}
			if (!Number.isFinite(init.timestamp)) {
				throw new TypeError('init.timestamp must be a number.');
			}
			if (init.duration !== undefined && (!Number.isFinite(init.duration) || init.duration < 0)) {
				throw new TypeError('init.duration, when provided, must be a non-negative number.');
			}

			this._data = toUint8Array(data).slice(); // Copy it

			this.format = init.format;
			this.codedWidth = init.codedWidth!;
			this.codedHeight = init.codedHeight!;
			this.rotation = init.rotation ?? 0;
			this.timestamp = init.timestamp!;
			this.duration = init.duration ?? 0;
			this.colorSpace = new VideoColorSpace(init.colorSpace);
		} else if (typeof VideoFrame !== 'undefined' && data instanceof VideoFrame) {
			if (init?.rotation !== undefined && ![0, 90, 180, 270].includes(init.rotation)) {
				throw new TypeError('init.rotation, when provided, must be 0, 90, 180, or 270.');
			}
			if (init?.timestamp !== undefined && !Number.isFinite(init?.timestamp)) {
				throw new TypeError('init.timestamp, when provided, must be a number.');
			}
			if (init?.duration !== undefined && (!Number.isFinite(init.duration) || init.duration < 0)) {
				throw new TypeError('init.duration, when provided, must be a non-negative number.');
			}

			this._data = data;

			this.format = data.format;
			// Copying the display dimensions here, assuming no innate VideoFrame rotation
			this.codedWidth = data.displayWidth;
			this.codedHeight = data.displayHeight;
			// The VideoFrame's rotation is ignored here. It's still a new field, and I'm not sure of any application
			// where the browser makes use of it. If a case gets found, I'll add it.
			this.rotation = init?.rotation ?? 0;
			this.timestamp = init?.timestamp ?? data.timestamp / 1e6;
			this.duration = init?.duration ?? (data.duration ?? 0) / 1e6;
			this.colorSpace = data.colorSpace;
		} else if (
			(typeof HTMLImageElement !== 'undefined' && data instanceof HTMLImageElement)
			|| (typeof SVGImageElement !== 'undefined' && data instanceof SVGImageElement)
			|| (typeof ImageBitmap !== 'undefined' && data instanceof ImageBitmap)
			|| (typeof HTMLVideoElement !== 'undefined' && data instanceof HTMLVideoElement)
			|| (typeof HTMLCanvasElement !== 'undefined' && data instanceof HTMLCanvasElement)
			|| (typeof OffscreenCanvas !== 'undefined' && data instanceof OffscreenCanvas)
		) {
			if (!init || typeof init !== 'object') {
				throw new TypeError('init must be an object.');
			}
			if (init.rotation !== undefined && ![0, 90, 180, 270].includes(init.rotation)) {
				throw new TypeError('init.rotation, when provided, must be 0, 90, 180, or 270.');
			}
			if (!Number.isFinite(init.timestamp)) {
				throw new TypeError('init.timestamp must be a number.');
			}
			if (init.duration !== undefined && (!Number.isFinite(init.duration) || init.duration < 0)) {
				throw new TypeError('init.duration, when provided, must be a non-negative number.');
			}

			if (typeof VideoFrame !== 'undefined') {
				return new VideoSample(
					new VideoFrame(data, {
						timestamp: Math.trunc(init.timestamp! * SECOND_TO_MICROSECOND_FACTOR),
						// Drag 0 to undefined
						duration: Math.trunc((init.duration ?? 0) * SECOND_TO_MICROSECOND_FACTOR) || undefined,
					}),
					init,
				);
			}

			let width = 0;
			let height = 0;

			// Determine the dimensions of the thing
			if ('naturalWidth' in data) {
				width = data.naturalWidth;
				height = data.naturalHeight;
			} else if ('videoWidth' in data) {
				width = data.videoWidth;
				height = data.videoHeight;
			} else if ('width' in data) {
				width = Number(data.width);
				height = Number(data.height);
			}

			if (!width || !height) {
				throw new TypeError('Could not determine dimensions.');
			}

			const canvas = new OffscreenCanvas(width, height);
			const context = canvas.getContext('2d', {
				alpha: isFirefox(), // Firefox has VideoFrame glitches with opaque canvases
				willReadFrequently: true,
			});
			assert(context);

			// Draw it to a canvas
			context.drawImage(data, 0, 0);
			this._data = canvas;

			this.format = 'RGBX';
			this.codedWidth = width;
			this.codedHeight = height;
			this.rotation = init.rotation ?? 0;
			this.timestamp = init.timestamp!;
			this.duration = init.duration ?? 0;
			this.colorSpace = new VideoColorSpace({
				matrix: 'rgb',
				primaries: 'bt709',
				transfer: 'iec61966-2-1',
				fullRange: true,
			});
		} else {
			throw new TypeError('Invalid data type: Must be a BufferSource or CanvasImageSource.');
		}
	}

	/** Clones this video sample. */
	clone() {
		if (this._closed) {
			throw new Error('VideoSample is closed.');
		}

		assert(this._data !== null);

		if (isVideoFrame(this._data)) {
			return new VideoSample(this._data.clone(), {
				timestamp: this.timestamp,
				duration: this.duration,
				rotation: this.rotation,
			});
		} else if (this._data instanceof Uint8Array) {
			return new VideoSample(this._data.slice(), {
				format: this.format!,
				codedWidth: this.codedWidth,
				codedHeight: this.codedHeight,
				timestamp: this.timestamp,
				duration: this.duration,
				colorSpace: this.colorSpace,
				rotation: this.rotation,
			});
		} else {
			return new VideoSample(this._data, {
				format: this.format!,
				codedWidth: this.codedWidth,
				codedHeight: this.codedHeight,
				timestamp: this.timestamp,
				duration: this.duration,
				colorSpace: this.colorSpace,
				rotation: this.rotation,
			});
		}
	}

	/**
	 * Closes this video sample, releasing held resources. Video samples should be closed as soon as they are not
	 * needed anymore.
	 */
	close() {
		if (this._closed) {
			return;
		}

		if (isVideoFrame(this._data)) {
			this._data.close();
		} else {
			this._data = null; // GC that shit
		}

		this._closed = true;
	}

	/** Returns the number of bytes required to hold this video sample's pixel data. */
	allocationSize() {
		if (this._closed) {
			throw new Error('VideoSample is closed.');
		}

		assert(this._data !== null);

		if (isVideoFrame(this._data)) {
			return this._data.allocationSize();
		} else if (this._data instanceof Uint8Array) {
			return this._data.byteLength;
		} else {
			return this.codedWidth * this.codedHeight * 4; // RGBX
		}
	}

	/** Copies this video sample's pixel data to an ArrayBuffer or ArrayBufferView. */
	async copyTo(destination: AllowSharedBufferSource) {
		if (!isAllowSharedBufferSource(destination)) {
			throw new TypeError('destination must be an ArrayBuffer or an ArrayBuffer view.');
		}

		if (this._closed) {
			throw new Error('VideoSample is closed.');
		}

		assert(this._data !== null);

		if (isVideoFrame(this._data)) {
			await this._data.copyTo(destination);
		} else if (this._data instanceof Uint8Array) {
			const dest = toUint8Array(destination);
			dest.set(this._data);
		} else {
			const canvas = this._data;
			const context = canvas.getContext('2d');
			assert(context);

			const imageData = context.getImageData(0, 0, this.codedWidth, this.codedHeight);
			const dest = toUint8Array(destination);
			dest.set(imageData.data);
		}
	}

	/**
	 * Converts this video sample to a VideoFrame for use with the WebCodecs API. The VideoFrame returned by this
	 * method *must* be closed separately from this video sample.
	 */
	toVideoFrame() {
		if (this._closed) {
			throw new Error('VideoSample is closed.');
		}

		assert(this._data !== null);

		if (isVideoFrame(this._data)) {
			return new VideoFrame(this._data, {
				timestamp: this.microsecondTimestamp,
				duration: this.microsecondDuration || undefined, // Drag 0 duration to undefined, glitches some codecs
			});
		} else if (this._data instanceof Uint8Array) {
			return new VideoFrame(this._data, {
				format: this.format!,
				codedWidth: this.codedWidth,
				codedHeight: this.codedHeight,
				timestamp: this.microsecondTimestamp,
				duration: this.microsecondDuration || undefined,
				colorSpace: this.colorSpace,
			});
		} else {
			return new VideoFrame(this._data, {
				timestamp: this.microsecondTimestamp,
				duration: this.microsecondDuration || undefined,
			});
		}
	}

	/**
	 * Draws the video sample to a 2D canvas context. Rotation metadata will be taken into account.
	 *
	 * @param dx - The x-coordinate in the destination canvas at which to place the top-left corner of the source image.
	 * @param dy - The y-coordinate in the destination canvas at which to place the top-left corner of the source image.
	 * @param dWidth - The width in pixels with which to draw the image in the destination canvas.
	 * @param dHeight - The height in pixels with which to draw the image in the destination canvas.
	 */
	draw(
		context: CanvasRenderingContext2D | OffscreenCanvasRenderingContext2D,
		dx: number,
		dy: number,
		dWidth?: number,
		dHeight?: number,
	): void;
	/**
	 * Draws the video sample to a 2D canvas context. Rotation metadata will be taken into account.
	 *
	 * @param sx - The x-coordinate of the top left corner of the sub-rectangle of the source image to draw into the
	 * destination context.
	 * @param sy - The y-coordinate of the top left corner of the sub-rectangle of the source image to draw into the
	 * destination context.
	 * @param sWidth - The width of the sub-rectangle of the source image to draw into the destination context.
	 * @param sHeight - The height of the sub-rectangle of the source image to draw into the destination context.
	 * @param dx - The x-coordinate in the destination canvas at which to place the top-left corner of the source image.
	 * @param dy - The y-coordinate in the destination canvas at which to place the top-left corner of the source image.
	 * @param dWidth - The width in pixels with which to draw the image in the destination canvas.
	 * @param dHeight - The height in pixels with which to draw the image in the destination canvas.
	 */
	draw(
		context: CanvasRenderingContext2D | OffscreenCanvasRenderingContext2D,
		sx: number,
		sy: number,
		sWidth: number,
		sHeight: number,
		dx: number,
		dy: number,
		dWidth?: number,
		dHeight?: number,
	): void;
	draw(
		context: CanvasRenderingContext2D | OffscreenCanvasRenderingContext2D,
		arg1: number,
		arg2: number,
		arg3?: number,
		arg4?: number,
		arg5?: number,
		arg6?: number,
		arg7?: number,
		arg8?: number,
	) {
		let sx = 0;
		let sy = 0;
		let sWidth = this.displayWidth;
		let sHeight = this.displayHeight;
		let dx = 0;
		let dy = 0;
		let dWidth = this.displayWidth;
		let dHeight = this.displayHeight;

		if (arg5 !== undefined) {
			sx = arg1!;
			sy = arg2!;
			sWidth = arg3!;
			sHeight = arg4!;
			dx = arg5;
			dy = arg6!;

			if (arg7 !== undefined) {
				dWidth = arg7;
				dHeight = arg8!;
			} else {
				dWidth = sWidth;
				dHeight = sHeight;
			}
		} else {
			dx = arg1;
			dy = arg2;

			if (arg3 !== undefined) {
				dWidth = arg3;
				dHeight = arg4!;
			}
		}

		if (!(
			(typeof CanvasRenderingContext2D !== 'undefined' && context instanceof CanvasRenderingContext2D)
			|| (
				typeof OffscreenCanvasRenderingContext2D !== 'undefined'
				&& context instanceof OffscreenCanvasRenderingContext2D
			)
		)) {
			throw new TypeError('context must be a CanvasRenderingContext2D or OffscreenCanvasRenderingContext2D.');
		}
		if (!Number.isFinite(sx)) {
			throw new TypeError('sx must be a number.');
		}
		if (!Number.isFinite(sy)) {
			throw new TypeError('sy must be a number.');
		}
		if (!Number.isFinite(sWidth) || sWidth < 0) {
			throw new TypeError('sWidth must be a non-negative number.');
		}
		if (!Number.isFinite(sHeight) || sHeight < 0) {
			throw new TypeError('sHeight must be a non-negative number.');
		}
		if (!Number.isFinite(dx)) {
			throw new TypeError('dx must be a number.');
		}
		if (!Number.isFinite(dy)) {
			throw new TypeError('dy must be a number.');
		}
		if (!Number.isFinite(dWidth) || dWidth < 0) {
			throw new TypeError('dWidth must be a non-negative number.');
		}
		if (!Number.isFinite(dHeight) || dHeight < 0) {
			throw new TypeError('dHeight must be a non-negative number.');
		}

		if (this._closed) {
			throw new Error('VideoSample is closed.');
		}

		({ sx, sy, sWidth, sHeight } = this._rotateSourceRegion(sx, sy, sWidth, sHeight, this.rotation));

		const source = this.toCanvasImageSource();

		context.save();

		const centerX = dx + dWidth / 2;
		const centerY = dy + dHeight / 2;

		context.translate(centerX, centerY);
		context.rotate(this.rotation * Math.PI / 180);

		const aspectRatioChange = this.rotation % 180 === 0 ? 1 : dWidth / dHeight;

		// Scale to compensate for aspect ratio changes when rotated
		context.scale(1 / aspectRatioChange, aspectRatioChange);

		context.drawImage(
			source,
			sx,
			sy,
			sWidth,
			sHeight,
			-dWidth / 2,
			-dHeight / 2,
			dWidth,
			dHeight,
		);

		// Restore the previous transformation state
		context.restore();
	}

	/**
	 * Draws the sample in the middle of the canvas corresponding to the context with the specified fit behavior.
	 */
	drawWithFit(context: CanvasRenderingContext2D | OffscreenCanvasRenderingContext2D, options: {
		/**
		 * Controls the fitting algorithm.
		 *
		 * - `'fill'` will stretch the image to fill the entire box, potentially altering aspect ratio.
		 * - `'contain'` will contain the entire image within the box while preserving aspect ratio. This may lead to
		 * letterboxing.
		 * - `'cover'` will scale the image until the entire box is filled, while preserving aspect ratio.
		 */
		fit: 'fill' | 'contain' | 'cover';
		/** A way to override rotation. Defaults to the rotation of the sample. */
		rotation?: Rotation;
		/**
		 * Specifies the rectangular region of the video sample to crop to. The crop region will automatically be
		 * clamped to the dimensions of the video sample. Cropping is performed after rotation but before resizing.
		 */
		crop?: CropRectangle;
	}) {
		if (!(
			(typeof CanvasRenderingContext2D !== 'undefined' && context instanceof CanvasRenderingContext2D)
			|| (
				typeof OffscreenCanvasRenderingContext2D !== 'undefined'
				&& context instanceof OffscreenCanvasRenderingContext2D
			)
		)) {
			throw new TypeError('context must be a CanvasRenderingContext2D or OffscreenCanvasRenderingContext2D.');
		}
		if (!options || typeof options !== 'object') {
			throw new TypeError('options must be an object.');
		}
		if (!['fill', 'contain', 'cover'].includes(options.fit)) {
			throw new TypeError('options.fit must be \'fill\', \'contain\', or \'cover\'.');
		}
		if (options.rotation !== undefined && ![0, 90, 180, 270].includes(options.rotation)) {
			throw new TypeError('options.rotation, when provided, must be 0, 90, 180, or 270.');
		}
		if (options.crop !== undefined) {
			validateCropRectangle(options.crop, 'options.');
		}

		const canvasWidth = context.canvas.width;
		const canvasHeight = context.canvas.height;
		const rotation = options.rotation ?? this.rotation;

		const [rotatedWidth, rotatedHeight] = rotation % 180 === 0
			? [this.codedWidth, this.codedHeight]
			: [this.codedHeight, this.codedWidth];

		if (options.crop) {
			clampCropRectangle(options.crop, rotatedWidth, rotatedHeight);
		}

		// These variables specify where the final sample will be drawn on the canvas
		let dx: number;
		let dy: number;
		let newWidth: number;
		let newHeight: number;

		const { sx, sy, sWidth, sHeight } = this._rotateSourceRegion(
			options.crop?.left ?? 0,
			options.crop?.top ?? 0,
			options.crop?.width ?? rotatedWidth,
			options.crop?.height ?? rotatedHeight,
			rotation,
		);

		if (options.fit === 'fill') {
			dx = 0;
			dy = 0;
			newWidth = canvasWidth;
			newHeight = canvasHeight;
		} else {
			const [sampleWidth, sampleHeight] = options.crop
				? [options.crop.width, options.crop.height]
				: [rotatedWidth, rotatedHeight];

			const scale = options.fit === 'contain'
				? Math.min(canvasWidth / sampleWidth, canvasHeight / sampleHeight)
				: Math.max(canvasWidth / sampleWidth, canvasHeight / sampleHeight);
			newWidth = sampleWidth * scale;
			newHeight = sampleHeight * scale;
			dx = (canvasWidth - newWidth) / 2;
			dy = (canvasHeight - newHeight) / 2;
		}

		const aspectRatioChange = rotation % 180 === 0 ? 1 : newWidth / newHeight;
		context.translate(canvasWidth / 2, canvasHeight / 2);
		context.rotate(rotation * Math.PI / 180);
		// This aspect ratio compensation is done so that we can draw the sample with the intended dimensions and
		// don't need to think about how those dimensions change after the rotation
		context.scale(1 / aspectRatioChange, aspectRatioChange);
		context.translate(-canvasWidth / 2, -canvasHeight / 2);

		// Important that we don't use .draw() here since that would take rotation into account, but we wanna handle it
		// ourselves here
		context.drawImage(this.toCanvasImageSource(), sx, sy, sWidth, sHeight, dx, dy, newWidth, newHeight);
	}

	/** @internal */
	_rotateSourceRegion(sx: number, sy: number, sWidth: number, sHeight: number, rotation: number) {
		// The provided sx,sy,sWidth,sHeight refer to the final rotated image, but that's not actually how the image is
		// stored. Therefore, we must map these back onto the original, pre-rotation image.
		if (rotation === 90) {
			[sx, sy, sWidth, sHeight] = [
				sy,
				this.codedHeight - sx - sWidth,
				sHeight,
				sWidth,
			];
		} else if (rotation === 180) {
			[sx, sy] = [
				this.codedWidth - sx - sWidth,
				this.codedHeight - sy - sHeight,
			];
		} else if (rotation === 270) {
			[sx, sy, sWidth, sHeight] = [
				this.codedWidth - sy - sHeight,
				sx,
				sHeight,
				sWidth,
			];
		}

		return { sx, sy, sWidth, sHeight };
	}

	/**
	 * Converts this video sample to a
	 * [`CanvasImageSource`](https://udn.realityripple.com/docs/Web/API/CanvasImageSource) for drawing to a canvas.
	 *
	 * You must use the value returned by this method immediately, as any VideoFrame created internally will
	 * automatically be closed in the next microtask.
	 */
	toCanvasImageSource() {
		if (this._closed) {
			throw new Error('VideoSample is closed.');
		}

		assert(this._data !== null);

		if (this._data instanceof Uint8Array) {
			// Requires VideoFrame to be defined
			const videoFrame = this.toVideoFrame();
			queueMicrotask(() => videoFrame.close()); // Let's automatically close the frame in the next microtask

			return videoFrame;
		} else {
			return this._data;
		}
	}

	/** Sets the rotation metadata of this video sample. */
	setRotation(newRotation: Rotation) {
		if (![0, 90, 180, 270].includes(newRotation)) {
			throw new TypeError('newRotation must be 0, 90, 180, or 270.');
		}

		// eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
		(this.rotation as Rotation) = newRotation;
	}

	/** Sets the presentation timestamp of this video sample, in seconds. */
	setTimestamp(newTimestamp: number) {
		if (!Number.isFinite(newTimestamp)) {
			throw new TypeError('newTimestamp must be a number.');
		}

		// eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
		(this.timestamp as number) = newTimestamp;
	}

	/** Sets the duration of this video sample, in seconds. */
	setDuration(newDuration: number) {
		if (!Number.isFinite(newDuration) || newDuration < 0) {
			throw new TypeError('newDuration must be a non-negative number.');
		}

		// eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
		(this.duration as number) = newDuration;
	}

	/** Calls `.close()`. */
	[Symbol.dispose]() {
		this.close();
	}
}

const isVideoFrame = (x: unknown): x is VideoFrame => {
	return typeof VideoFrame !== 'undefined' && x instanceof VideoFrame;
};

/**
 * Specifies the rectangular cropping region.
 * @group Miscellaneous
 * @public
 */
export type CropRectangle = {
	/** The distance in pixels from the left edge of the source frame to the left edge of the crop rectangle. */
	left: number;
	/** The distance in pixels from the top edge of the source frame to the top edge of the crop rectangle. */
	top: number;
	/** The width in pixels of the crop rectangle. */
	width: number;
	/** The height in pixels of the crop rectangle. */
	height: number;
};

export const clampCropRectangle = (crop: CropRectangle, outerWidth: number, outerHeight: number) => {
	crop.left = Math.min(crop.left, outerWidth);
	crop.top = Math.min(crop.top, outerHeight);
	crop.width = Math.min(crop.width, outerWidth - crop.left);
	crop.height = Math.min(crop.height, outerHeight - crop.top);

	assert(crop.width >= 0);
	assert(crop.height >= 0);
};

export const validateCropRectangle = (crop: CropRectangle, prefix: string) => {
	if (!crop || typeof crop !== 'object') {
		throw new TypeError(prefix + 'crop, when provided, must be an object.');
	}
	if (!Number.isInteger(crop.left) || crop.left < 0) {
		throw new TypeError(prefix + 'crop.left must be a non-negative integer.');
	}
	if (!Number.isInteger(crop.top) || crop.top < 0) {
		throw new TypeError(prefix + 'crop.top must be a non-negative integer.');
	}
	if (!Number.isInteger(crop.width) || crop.width < 0) {
		throw new TypeError(prefix + 'crop.width must be a non-negative integer.');
	}
	if (!Number.isInteger(crop.height) || crop.height < 0) {
		throw new TypeError(prefix + 'crop.height must be a non-negative integer.');
	}
};

const AUDIO_SAMPLE_FORMATS = new Set(
	['f32', 'f32-planar', 's16', 's16-planar', 's32', 's32-planar', 'u8', 'u8-planar'],
);

/**
 * Metadata used for AudioSample initialization.
 * @group Samples
 * @public
 */
export type AudioSampleInit = {
	/** The audio data for this sample. */
	data: AllowSharedBufferSource;
	/**
	 * The audio sample format. [See sample formats](https://developer.mozilla.org/en-US/docs/Web/API/AudioData/format)
	 */
	format: AudioSampleFormat;
	/** The number of audio channels. */
	numberOfChannels: number;
	/** The audio sample rate in hertz. */
	sampleRate: number;
	/** The presentation timestamp of the sample in seconds. */
	timestamp: number;
};

/**
 * Options used for copying audio sample data.
 * @group Samples
 * @public
 */
export type AudioSampleCopyToOptions = {
	/**
	 * The index identifying the plane to copy from. This must be 0 if using a non-planar (interleaved) output format.
	 */
	planeIndex: number;
	/**
	 * The output format for the destination data. Defaults to the AudioSample's format.
	 * [See sample formats](https://developer.mozilla.org/en-US/docs/Web/API/AudioData/format)
	 */
	format?: AudioSampleFormat;
	/** An offset into the source plane data indicating which frame to begin copying from. Defaults to 0. */
	frameOffset?: number;
	/**
	 * The number of frames to copy. If not provided, the copy will include all frames in the plane beginning
	 * with frameOffset.
	 */
	frameCount?: number;
};

/**
 * Represents a raw, unencoded audio sample. Mainly used as an expressive wrapper around WebCodecs API's
 * [`AudioData`](https://developer.mozilla.org/en-US/docs/Web/API/AudioData), but can also be used standalone.
 * @group Samples
 * @public
 */
export class AudioSample implements Disposable {
	/** @internal */
	_data: AudioData | Uint8Array;
	/** @internal */
	_closed: boolean = false;

	/**
	 * The audio sample format.
	 * [See sample formats](https://developer.mozilla.org/en-US/docs/Web/API/AudioData/format)
	 */
	readonly format: AudioSampleFormat;
	/** The audio sample rate in hertz. */
	readonly sampleRate: number;
	/**
	 * The number of audio frames in the sample, per channel. In other words, the length of this audio sample in frames.
	 */
	readonly numberOfFrames: number;
	/** The number of audio channels. */
	readonly numberOfChannels: number;
	/** The duration of the sample in seconds. */
	readonly duration: number;
	/**
	 * The presentation timestamp of the sample in seconds. May be negative. Samples with negative end timestamps should
	 * not be presented.
	 */
	readonly timestamp: number;

	/** The presentation timestamp of the sample in microseconds. */
	get microsecondTimestamp() {
		return Math.trunc(SECOND_TO_MICROSECOND_FACTOR * this.timestamp);
	}

	/** The duration of the sample in microseconds. */
	get microsecondDuration() {
		return Math.trunc(SECOND_TO_MICROSECOND_FACTOR * this.duration);
	}

	/**
	 * Creates a new {@link AudioSample}, either from an existing
	 * [`AudioData`](https://developer.mozilla.org/en-US/docs/Web/API/AudioData) or from raw bytes specified in
	 * {@link AudioSampleInit}.
	 */
	constructor(init: AudioData | AudioSampleInit) {
		if (isAudioData(init)) {
			if (init.format === null) {
				throw new TypeError('AudioData with null format is not supported.');
			}

			this._data = init;

			this.format = init.format;
			this.sampleRate = init.sampleRate;
			this.numberOfFrames = init.numberOfFrames;
			this.numberOfChannels = init.numberOfChannels;
			this.timestamp = init.timestamp / 1e6;
			this.duration = init.numberOfFrames / init.sampleRate;
		} else {
			if (!init || typeof init !== 'object') {
				throw new TypeError('Invalid AudioDataInit: must be an object.');
			}

			if (!AUDIO_SAMPLE_FORMATS.has(init.format)) {
				throw new TypeError('Invalid AudioDataInit: invalid format.');
			}
			if (!Number.isFinite(init.sampleRate) || init.sampleRate <= 0) {
				throw new TypeError('Invalid AudioDataInit: sampleRate must be > 0.');
			}
			if (!Number.isInteger(init.numberOfChannels) || init.numberOfChannels === 0) {
				throw new TypeError('Invalid AudioDataInit: numberOfChannels must be an integer > 0.');
			}
			if (!Number.isFinite(init?.timestamp)) {
				throw new TypeError('init.timestamp must be a number.');
			}

			const numberOfFrames
				= init.data.byteLength / (getBytesPerSample(init.format) * init.numberOfChannels);
			if (!Number.isInteger(numberOfFrames)) {
				throw new TypeError('Invalid AudioDataInit: data size is not a multiple of frame size.');
			}

			this.format = init.format;
			this.sampleRate = init.sampleRate;
			this.numberOfFrames = numberOfFrames;
			this.numberOfChannels = init.numberOfChannels;
			this.timestamp = init.timestamp;
			this.duration = numberOfFrames / init.sampleRate;

			let dataBuffer: Uint8Array;
			if (init.data instanceof ArrayBuffer) {
				dataBuffer = new Uint8Array(init.data);
			} else if (ArrayBuffer.isView(init.data)) {
				dataBuffer = new Uint8Array(init.data.buffer, init.data.byteOffset, init.data.byteLength);
			} else {
				throw new TypeError('Invalid AudioDataInit: data is not a BufferSource.');
			}

			const expectedSize
                = this.numberOfFrames * this.numberOfChannels * getBytesPerSample(this.format);
			if (dataBuffer.byteLength < expectedSize) {
				throw new TypeError('Invalid AudioDataInit: insufficient data size.');
			}

			this._data = dataBuffer;
		}
	}

	/** Returns the number of bytes required to hold the audio sample's data as specified by the given options. */
	allocationSize(options: AudioSampleCopyToOptions) {
		if (!options || typeof options !== 'object') {
			throw new TypeError('options must be an object.');
		}
		if (!Number.isInteger(options.planeIndex) || options.planeIndex < 0) {
			throw new TypeError('planeIndex must be a non-negative integer.');
		}

		if (options.format !== undefined && !AUDIO_SAMPLE_FORMATS.has(options.format)) {
			throw new TypeError('Invalid format.');
		}
		if (options.frameOffset !== undefined && (!Number.isInteger(options.frameOffset) || options.frameOffset < 0)) {
			throw new TypeError('frameOffset must be a non-negative integer.');
		}
		if (options.frameCount !== undefined && (!Number.isInteger(options.frameCount) || options.frameCount < 0)) {
			throw new TypeError('frameCount must be a non-negative integer.');
		}

		if (this._closed) {
			throw new Error('AudioSample is closed.');
		}

		const destFormat = options.format ?? this.format;

		const frameOffset = options.frameOffset ?? 0;
		if (frameOffset >= this.numberOfFrames) {
			throw new RangeError('frameOffset out of range');
		}

		const copyFrameCount
            = options.frameCount !== undefined ? options.frameCount : (this.numberOfFrames - frameOffset);
		if (copyFrameCount > (this.numberOfFrames - frameOffset)) {
			throw new RangeError('frameCount out of range');
		}

		const bytesPerSample = getBytesPerSample(destFormat);
		const isPlanar = formatIsPlanar(destFormat);
		if (isPlanar && options.planeIndex >= this.numberOfChannels) {
			throw new RangeError('planeIndex out of range');
		}
		if (!isPlanar && options.planeIndex !== 0) {
			throw new RangeError('planeIndex out of range');
		}

		const elementCount = isPlanar ? copyFrameCount : copyFrameCount * this.numberOfChannels;
		return elementCount * bytesPerSample;
	}

	/** Copies the audio sample's data to an ArrayBuffer or ArrayBufferView as specified by the given options. */
	copyTo(destination: AllowSharedBufferSource, options: AudioSampleCopyToOptions) {
		if (!isAllowSharedBufferSource(destination)) {
			throw new TypeError('destination must be an ArrayBuffer or an ArrayBuffer view.');
		}
		if (!options || typeof options !== 'object') {
			throw new TypeError('options must be an object.');
		}
		if (!Number.isInteger(options.planeIndex) || options.planeIndex < 0) {
			throw new TypeError('planeIndex must be a non-negative integer.');
		}

		if (options.format !== undefined && !AUDIO_SAMPLE_FORMATS.has(options.format)) {
			throw new TypeError('Invalid format.');
		}
		if (options.frameOffset !== undefined && (!Number.isInteger(options.frameOffset) || options.frameOffset < 0)) {
			throw new TypeError('frameOffset must be a non-negative integer.');
		}
		if (options.frameCount !== undefined && (!Number.isInteger(options.frameCount) || options.frameCount < 0)) {
			throw new TypeError('frameCount must be a non-negative integer.');
		}

		if (this._closed) {
			throw new Error('AudioSample is closed.');
		}

		const { planeIndex, format, frameCount: optFrameCount, frameOffset: optFrameOffset } = options;

		const destFormat = format ?? this.format;
		if (!destFormat) throw new Error('Destination format not determined');

		const numFrames = this.numberOfFrames;
		const numChannels = this.numberOfChannels;
		const frameOffset = optFrameOffset ?? 0;
		if (frameOffset >= numFrames) {
			throw new RangeError('frameOffset out of range');
		}

		const copyFrameCount = optFrameCount !== undefined ? optFrameCount : (numFrames - frameOffset);
		if (copyFrameCount > (numFrames - frameOffset)) {
			throw new RangeError('frameCount out of range');
		}

		const destBytesPerSample = getBytesPerSample(destFormat);
		const destIsPlanar = formatIsPlanar(destFormat);
		if (destIsPlanar && planeIndex >= numChannels) {
			throw new RangeError('planeIndex out of range');
		}
		if (!destIsPlanar && planeIndex !== 0) {
			throw new RangeError('planeIndex out of range');
		}

		const destElementCount = destIsPlanar ? copyFrameCount : copyFrameCount * numChannels;
		const requiredSize = destElementCount * destBytesPerSample;
		if (destination.byteLength < requiredSize) {
			throw new RangeError('Destination buffer is too small');
		}

		const destView = toDataView(destination);
		const writeFn = getWriteFunction(destFormat);

		if (isAudioData(this._data)) {
			if (destIsPlanar) {
				if (destFormat === 'f32-planar') {
					// Simple, since the browser must support f32-planar, we can just delegate here
					this._data.copyTo(destination, {
						planeIndex,
						frameOffset,
						frameCount: copyFrameCount,
						format: 'f32-planar',
					});
				} else {
					// Allocate temporary buffer for f32-planar data
					const tempBuffer = new ArrayBuffer(copyFrameCount * 4);
					const tempArray = new Float32Array(tempBuffer);
					this._data.copyTo(tempArray, {
						planeIndex,
						frameOffset,
						frameCount: copyFrameCount,
						format: 'f32-planar',
					});

					// Convert each f32 sample to destination format
					const tempView = new DataView(tempBuffer);
					for (let i = 0; i < copyFrameCount; i++) {
						const destOffset = i * destBytesPerSample;
						const sample = tempView.getFloat32(i * 4, true);
						writeFn(destView, destOffset, sample);
					}
				}
			} else {
				// Destination is interleaved.
				// Allocate a temporary Float32Array to hold one channel's worth of data.
				const numCh = numChannels;
				const temp = new Float32Array(copyFrameCount);
				for (let ch = 0; ch < numCh; ch++) {
					this._data.copyTo(temp, {
						planeIndex: ch,
						frameOffset,
						frameCount: copyFrameCount,
						format: 'f32-planar',
					});
					for (let i = 0; i < copyFrameCount; i++) {
						const destIndex = i * numCh + ch;
						const destOffset = destIndex * destBytesPerSample;
						writeFn(destView, destOffset, temp[i]!);
					}
				}
			}
		} else {
			// Branch for Uint8Array data (non-AudioData)
			const uint8Data = this._data;
			const srcView = new DataView(uint8Data.buffer, uint8Data.byteOffset, uint8Data.byteLength);

			const srcFormat = this.format;
			const readFn = getReadFunction(srcFormat);
			const srcBytesPerSample = getBytesPerSample(srcFormat);
			const srcIsPlanar = formatIsPlanar(srcFormat);

			for (let i = 0; i < copyFrameCount; i++) {
				if (destIsPlanar) {
					const destOffset = i * destBytesPerSample;
					let srcOffset: number;
					if (srcIsPlanar) {
						srcOffset = (planeIndex * numFrames + (i + frameOffset)) * srcBytesPerSample;
					} else {
						srcOffset = (((i + frameOffset) * numChannels) + planeIndex) * srcBytesPerSample;
					}

					const normalized = readFn(srcView, srcOffset);
					writeFn(destView, destOffset, normalized);
				} else {
					for (let ch = 0; ch < numChannels; ch++) {
						const destIndex = i * numChannels + ch;
						const destOffset = destIndex * destBytesPerSample;
						let srcOffset: number;
						if (srcIsPlanar) {
							srcOffset = (ch * numFrames + (i + frameOffset)) * srcBytesPerSample;
						} else {
							srcOffset = (((i + frameOffset) * numChannels) + ch) * srcBytesPerSample;
						}

						const normalized = readFn(srcView, srcOffset);
						writeFn(destView, destOffset, normalized);
					}
				}
			}
		}
	}

	/** Clones this audio sample. */
	clone(): AudioSample {
		if (this._closed) {
			throw new Error('AudioSample is closed.');
		}

		if (isAudioData(this._data)) {
			const sample = new AudioSample(this._data.clone());
			sample.setTimestamp(this.timestamp); // Make sure the timestamp is precise (beyond microsecond accuracy)

			return sample;
		} else {
			return new AudioSample({
				format: this.format,
				sampleRate: this.sampleRate,
				numberOfFrames: this.numberOfFrames,
				numberOfChannels: this.numberOfChannels,
				timestamp: this.timestamp,
				data: this._data,
			});
		}
	}

	/**
	 * Closes this audio sample, releasing held resources. Audio samples should be closed as soon as they are not
	 * needed anymore.
	 */
	close(): void {
		if (this._closed) {
			return;
		}

		if (isAudioData(this._data)) {
			this._data.close();
		} else {
			this._data = new Uint8Array(0);
		}

		this._closed = true;
	}

	/**
	 * Converts this audio sample to an AudioData for use with the WebCodecs API. The AudioData returned by this
	 * method *must* be closed separately from this audio sample.
	 */
	toAudioData() {
		if (this._closed) {
			throw new Error('AudioSample is closed.');
		}

		if (isAudioData(this._data)) {
			if (this._data.timestamp === this.microsecondTimestamp) {
				// Timestamp matches, let's just return the data (but cloned)
				return this._data.clone();
			} else {
				// It's impossible to simply change an AudioData's timestamp, so we'll need to create a new one
				if (formatIsPlanar(this.format)) {
					const size = this.allocationSize({ planeIndex: 0, format: this.format });
					const data = new ArrayBuffer(size * this.numberOfChannels);

					// We gotta read out each plane individually
					for (let i = 0; i < this.numberOfChannels; i++) {
						this.copyTo(new Uint8Array(data, i * size, size), { planeIndex: i, format: this.format });
					}

					return new AudioData({
						format: this.format,
						sampleRate: this.sampleRate,
						numberOfFrames: this.numberOfFrames,
						numberOfChannels: this.numberOfChannels,
						timestamp: this.microsecondTimestamp,
						data,
					});
				} else {
					const data = new ArrayBuffer(this.allocationSize({ planeIndex: 0, format: this.format }));
					this.copyTo(data, { planeIndex: 0, format: this.format });

					return new AudioData({
						format: this.format,
						sampleRate: this.sampleRate,
						numberOfFrames: this.numberOfFrames,
						numberOfChannels: this.numberOfChannels,
						timestamp: this.microsecondTimestamp,
						data,
					});
				}
			}
		} else {
			return new AudioData({
				format: this.format,
				sampleRate: this.sampleRate,
				numberOfFrames: this.numberOfFrames,
				numberOfChannels: this.numberOfChannels,
				timestamp: this.microsecondTimestamp,
				data: this._data,
			});
		}
	}

	/** Convert this audio sample to an AudioBuffer for use with the Web Audio API. */
	toAudioBuffer() {
		if (this._closed) {
			throw new Error('AudioSample is closed.');
		}

		const audioBuffer = new AudioBuffer({
			numberOfChannels: this.numberOfChannels,
			length: this.numberOfFrames,
			sampleRate: this.sampleRate,
		});

		const dataBytes = new Float32Array(this.allocationSize({ planeIndex: 0, format: 'f32-planar' }) / 4);

		for (let i = 0; i < this.numberOfChannels; i++) {
			this.copyTo(dataBytes, { planeIndex: i, format: 'f32-planar' });
			audioBuffer.copyToChannel(dataBytes, i);
		}

		return audioBuffer;
	}

	/** Sets the presentation timestamp of this audio sample, in seconds. */
	setTimestamp(newTimestamp: number) {
		if (!Number.isFinite(newTimestamp)) {
			throw new TypeError('newTimestamp must be a number.');
		}

		// eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
		(this.timestamp as number) = newTimestamp;
	}

	/** Calls `.close()`. */
	[Symbol.dispose]() {
		this.close();
	}

	/** @internal */
	static* _fromAudioBuffer(audioBuffer: AudioBuffer, timestamp: number) {
		if (!(audioBuffer instanceof AudioBuffer)) {
			throw new TypeError('audioBuffer must be an AudioBuffer.');
		}

		const MAX_FLOAT_COUNT = 48000 * 5; // 5 seconds of mono 48 kHz audio per sample

		const numberOfChannels = audioBuffer.numberOfChannels;
		const sampleRate = audioBuffer.sampleRate;
		const totalFrames = audioBuffer.length;
		const maxFramesPerChunk = Math.floor(MAX_FLOAT_COUNT / numberOfChannels);

		let currentRelativeFrame = 0;
		let remainingFrames = totalFrames;

		// Create AudioSamples in a chunked fashion so we don't create huge Float32Arrays
		while (remainingFrames > 0) {
			const framesToCopy = Math.min(maxFramesPerChunk, remainingFrames);
			const chunkData = new Float32Array(numberOfChannels * framesToCopy);

			for (let channel = 0; channel < numberOfChannels; channel++) {
				audioBuffer.copyFromChannel(
					chunkData.subarray(channel * framesToCopy, (channel + 1) * framesToCopy),
					channel,
					currentRelativeFrame,
				);
			}

			yield new AudioSample({
				format: 'f32-planar',
				sampleRate,
				numberOfFrames: framesToCopy,
				numberOfChannels,
				timestamp: timestamp + currentRelativeFrame / sampleRate,
				data: chunkData,
			});

			currentRelativeFrame += framesToCopy;
			remainingFrames -= framesToCopy;
		}
	}

	/**
	 * Creates AudioSamples from an AudioBuffer, starting at the given timestamp in seconds. Typically creates exactly
	 * one sample, but may create multiple if the AudioBuffer is exceedingly large.
	 */
	static fromAudioBuffer(audioBuffer: AudioBuffer, timestamp: number) {
		if (!(audioBuffer instanceof AudioBuffer)) {
			throw new TypeError('audioBuffer must be an AudioBuffer.');
		}

		const MAX_FLOAT_COUNT = 48000 * 5; // 5 seconds of mono 48 kHz audio per sample

		const numberOfChannels = audioBuffer.numberOfChannels;
		const sampleRate = audioBuffer.sampleRate;
		const totalFrames = audioBuffer.length;
		const maxFramesPerChunk = Math.floor(MAX_FLOAT_COUNT / numberOfChannels);

		let currentRelativeFrame = 0;
		let remainingFrames = totalFrames;

		const result: AudioSample[] = [];

		// Create AudioSamples in a chunked fashion so we don't create huge Float32Arrays
		while (remainingFrames > 0) {
			const framesToCopy = Math.min(maxFramesPerChunk, remainingFrames);
			const chunkData = new Float32Array(numberOfChannels * framesToCopy);

			for (let channel = 0; channel < numberOfChannels; channel++) {
				audioBuffer.copyFromChannel(
					chunkData.subarray(channel * framesToCopy, (channel + 1) * framesToCopy),
					channel,
					currentRelativeFrame,
				);
			}

			const audioSample = new AudioSample({
				format: 'f32-planar',
				sampleRate,
				numberOfFrames: framesToCopy,
				numberOfChannels,
				timestamp: timestamp + currentRelativeFrame / sampleRate,
				data: chunkData,
			});

			result.push(audioSample);

			currentRelativeFrame += framesToCopy;
			remainingFrames -= framesToCopy;
		}

		return result;
	}
}

const getBytesPerSample = (format: AudioSampleFormat): number => {
	switch (format) {
		case 'u8':
		case 'u8-planar':
			return 1;
		case 's16':
		case 's16-planar':
			return 2;
		case 's32':
		case 's32-planar':
			return 4;
		case 'f32':
		case 'f32-planar':
			return 4;
		default:
			throw new Error('Unknown AudioSampleFormat');
	}
};

const formatIsPlanar = (format: AudioSampleFormat): boolean => {
	switch (format) {
		case 'u8-planar':
		case 's16-planar':
		case 's32-planar':
		case 'f32-planar':
			return true;
		default:
			return false;
	}
};

const getReadFunction = (format: AudioSampleFormat): (view: DataView, offset: number) => number => {
	switch (format) {
		case 'u8':
		case 'u8-planar':
			return (view, offset) => (view.getUint8(offset) - 128) / 128;
		case 's16':
		case 's16-planar':
			return (view, offset) => view.getInt16(offset, true) / 32768;
		case 's32':
		case 's32-planar':
			return (view, offset) => view.getInt32(offset, true) / 2147483648;
		case 'f32':
		case 'f32-planar':
			return (view, offset) => view.getFloat32(offset, true);
	}
};

const getWriteFunction = (format: AudioSampleFormat): (view: DataView, offset: number, value: number) => void => {
	switch (format) {
		case 'u8':
		case 'u8-planar':
			return (view, offset, value) =>
				view.setUint8(offset, clamp((value + 1) * 127.5, 0, 255));
		case 's16':
		case 's16-planar':
			return (view, offset, value) =>
				view.setInt16(offset, clamp(Math.round(value * 32767), -32768, 32767), true);
		case 's32':
		case 's32-planar':
			return (view, offset, value) =>
				view.setInt32(offset, clamp(Math.round(value * 2147483647), -2147483648, 2147483647), true);
		case 'f32':
		case 'f32-planar':
			return (view, offset, value) => view.setFloat32(offset, value, true);
	}
};

const isAudioData = (x: unknown): x is AudioData => {
	return typeof AudioData !== 'undefined' && x instanceof AudioData;
};