Implement audio decoder & encoder

packages/server/src/audio-decoder.ts

@@ -0,0 +1,106 @@
+import { AudioCodec, AudioSample, CustomAudioDecoder, EncodedPacket, MaybePromise } from 'mediabunny';
+import * as NodeAv from 'node-av';
+import { CODEC_TO_CODEC_ID, getChannelLayout } from './misc';
+import { assert, roundToDivisor, toUint8Array } from '../../../src/misc';
+import { NodeAvFrameAudioSampleResource } from './audio-sample';
+
+export class NodeAvAudioDecoder extends CustomAudioDecoder {
+	frame!: NodeAv.Frame;
+	packet!: NodeAv.Packet;
+	codecContext!: NodeAv.CodecContext;
+
+	// eslint-disable-next-line @typescript-eslint/no-unused-vars
+	static override supports(codec: AudioCodec, config: AudioDecoderConfig): boolean {
+		return codec === 'aac'
+			|| codec === 'opus'
+			|| codec === 'mp3'
+			|| codec === 'vorbis'
+			|| codec === 'flac'
+			|| codec === 'ac3'
+			|| codec === 'eac3';
+	}
+
+	async init(): Promise<void> {
+		this.frame = new NodeAv.Frame();
+		this.frame.alloc();
+		this.packet = new NodeAv.Packet();
+		this.packet.alloc();
+
+		const codecId = CODEC_TO_CODEC_ID[this.codec];
+		assert(codecId !== undefined);
+
+		const codec = NodeAv.Codec.findDecoder(codecId);
+		if (codec === null) {
+			throw new Error(`Unable to obtain libav codec for '${this.codec}'.`);
+		}
+
+		const codecContext = new NodeAv.CodecContext();
+		codecContext.allocContext3(codec);
+
+		codecContext.sampleRate = this.config.sampleRate;
+		codecContext.channelLayout = getChannelLayout(this.config.numberOfChannels);
+		codecContext.codecType = NodeAv.AVMEDIA_TYPE_AUDIO;
+		codecContext.codecId = codecId;
+		codecContext.extraData = this.config.description
+			? Buffer.from(toUint8Array(this.config.description))
+			: null;
+
+		const ret = await codecContext.open2();
+		NodeAv.FFmpegError.throwIfError(ret, 'Open codec context');
+
+		this.codecContext = codecContext;
+	}
+
+	async decode(packet: EncodedPacket): Promise<void> {
+		this.packet.isKeyframe = packet.type === 'key';
+		this.packet.data = Buffer.from(packet.data);
+		this.packet.timeBase = { num: 1, den: 1e6 };
+		this.packet.pts = BigInt(packet.microsecondTimestamp);
+		this.packet.dts = NodeAv.AV_NOPTS_VALUE;
+		this.packet.duration = BigInt(packet.microsecondDuration);
+
+		const ret = await this.codecContext.sendPacket(this.packet);
+		NodeAv.FFmpegError.throwIfError(ret, 'Send packet');
+
+		while (true) {
+			const receiveRet = await this.codecContext.receiveFrame(this.frame);
+			if (receiveRet === NodeAv.AVERROR_EAGAIN || receiveRet === NodeAv.AVERROR_EOF) {
+				break;
+			}
+
+			this.receiveFrame(receiveRet);
+		}
+	}
+
+	receiveFrame(ret: number) {
+		NodeAv.FFmpegError.throwIfError(ret, 'Receive frame');
+
+		const timestamp = roundToDivisor(Number(this.frame.pts) / 1e6, this.config.sampleRate);
+		this.onSample(new AudioSample(new NodeAvFrameAudioSampleResource(this.frame, timestamp)));
+	}
+
+	async flush(): Promise<void> {
+		// Send null packet to signal flush
+		const ret = await this.codecContext.sendPacket(null);
+		NodeAv.FFmpegError.throwIfError(ret, 'Flush decoder');
+
+		// Keep receiving frames until no more are available
+		while (true) {
+			const receiveRet = await this.codecContext.receiveFrame(this.frame);
+			if (receiveRet === NodeAv.AVERROR_EAGAIN || receiveRet === NodeAv.AVERROR_EOF) {
+				// No more frames available
+				break;
+			}
+
+			this.receiveFrame(receiveRet);
+		}
+
+		this.codecContext.flushBuffers();
+	}
+
+	close(): MaybePromise<void> {
+		this.codecContext.freeContext();
+		this.frame.free();
+		this.packet.free();
+	}
+}

packages/server/src/audio-encoder.ts

@@ -0,0 +1,370 @@
+import { AudioCodec, AudioSample, CustomAudioEncoder, MaybePromise, QUALITY_MEDIUM } from 'mediabunny';
+import * as NodeAv from 'node-av';
+import { CODEC_TO_CODEC_ID, fromAudioSampleFormat, getChannelLayout } from './misc';
+import { assert, toUint8Array } from '../../../src/misc';
+import { NodeAvFrameAudioSampleResource } from './audio-sample';
+import { AdtsHeaderTemplate, buildAdtsHeaderTemplate, parseAacAudioSpecificConfig } from '../../../shared/aac-misc';
+import { EncodedPacket } from 'mediabunny';
+
+const AAC_SAMPLE_RATES
+	= [96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, 16000, 12000, 11025, 8000, 7350];
+const OPUS_SAMPLE_RATES = [8000, 12000, 16000, 24000, 48000];
+const MP3_SAMPLE_RATES = [8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000];
+const AC3_SAMPLE_RATES = [32000, 44100, 48000];
+
+const FRAME_SIZE_FALLBACK = 1024; // Just 'cause
+
+export class NodeAvAudioEncoder extends CustomAudioEncoder {
+	frame!: NodeAv.Frame;
+	packet!: NodeAv.Packet;
+	avCodec!: NodeAv.Codec;
+	codecContext: NodeAv.CodecContext | null = null;
+	firstExpectedTimestamp: number | null = null;
+	outputTimestampOffset = 0;
+
+	resampler: NodeAv.SoftwareResampleContext | null = null;
+	inputParametersKey: string | null = null;
+	resamplerInputSampleRate: number | null = null;
+	nextResamplerPts: bigint | null = null;
+	dstFrame: NodeAv.Frame | null = null;
+	packetEmitted = false;
+	adtsHeaderTemplate: AdtsHeaderTemplate | null = null;
+
+	static override supports(codec: AudioCodec, config: AudioEncoderConfig): boolean {
+		const { numberOfChannels, sampleRate } = config;
+
+		return (
+			codec === 'aac' && numberOfChannels >= 1 && numberOfChannels <= 48
+			&& AAC_SAMPLE_RATES.includes(sampleRate)
+		) || (
+			codec === 'opus' && numberOfChannels >= 1 && numberOfChannels <= 255
+			&& OPUS_SAMPLE_RATES.includes(sampleRate)
+		) || (
+			codec === 'mp3' && numberOfChannels >= 1 && numberOfChannels <= 2
+			&& MP3_SAMPLE_RATES.includes(sampleRate)
+		) || (
+			codec === 'vorbis' && numberOfChannels >= 1 && numberOfChannels <= 255
+			&& sampleRate <= 200000
+		) || (
+			codec === 'flac' && numberOfChannels >= 1 && numberOfChannels <= 8
+			&& sampleRate <= 655350
+		) || (
+			codec === 'ac3' && numberOfChannels >= 1 && numberOfChannels <= 6
+			&& AC3_SAMPLE_RATES.includes(sampleRate)
+		) || (
+			codec === 'eac3' && numberOfChannels >= 1 && numberOfChannels <= 16
+			&& AC3_SAMPLE_RATES.includes(sampleRate)
+		);
+	}
+
+	async init(): Promise<void> {
+		this.frame = new NodeAv.Frame();
+		this.frame.alloc();
+		this.packet = new NodeAv.Packet();
+		this.packet.alloc();
+
+		const codecId = CODEC_TO_CODEC_ID[this.codec];
+		assert(codecId !== undefined);
+
+		const codec = NodeAv.Codec.findEncoder(codecId);
+		if (!codec) {
+			throw new Error(`Unable to obtain libav codec for '${this.codec}'.`);
+		}
+
+		this.avCodec = codec;
+
+		await this.createCodecContext();
+	}
+
+	async createCodecContext() {
+		assert(this.codecContext === null);
+
+		const codecContext = new NodeAv.CodecContext();
+		codecContext.allocContext3(this.avCodec);
+
+		let sampleFormat = NodeAv.AV_SAMPLE_FMT_FLTP;
+		if (this.avCodec.sampleFormats && !this.avCodec.sampleFormats.includes(NodeAv.AV_SAMPLE_FMT_FLTP)) {
+			// Use a format that's supported
+			sampleFormat = this.avCodec.sampleFormats[0]!;
+		}
+
+		codecContext.sampleRate = this.config.sampleRate;
+		codecContext.channelLayout = getChannelLayout(this.config.numberOfChannels);
+		codecContext.codecType = NodeAv.AVMEDIA_TYPE_AUDIO;
+		codecContext.codecId = CODEC_TO_CODEC_ID[this.codec]!;
+		codecContext.sampleFormat = sampleFormat;
+		codecContext.timeBase = new NodeAv.Rational(1, this.config.sampleRate);
+		codecContext.bitRate = BigInt(this.config.bitrate ?? QUALITY_MEDIUM._toAudioBitrate(this.codec) ?? 0);
+
+		if (this.config.bitrateMode === 'constant') {
+			codecContext.rcMinRate = codecContext.bitRate;
+			codecContext.rcMaxRate = codecContext.bitRate;
+		}
+
+		const ret = await codecContext.open2();
+		NodeAv.FFmpegError.throwIfError(ret, 'Open codec context');
+
+		this.codecContext = codecContext;
+	}
+
+	async encode(audioSample: AudioSample): Promise<void> {
+		if (this.codecContext === null) {
+			await this.createCodecContext();
+			assert(this.codecContext);
+		}
+
+		this.firstExpectedTimestamp ??= audioSample.timestamp;
+
+		if (audioSample._data instanceof NodeAvFrameAudioSampleResource) {
+			this.frame.ref(audioSample._data.frame);
+		} else {
+			// Copy audio data from AudioData to FFmpeg Frame
+			const format = fromAudioSampleFormat(audioSample.format);
+			this.frame.format = format;
+			this.frame.nbSamples = audioSample.numberOfFrames;
+			this.frame.sampleRate = audioSample.sampleRate;
+			this.frame.channelLayout = getChannelLayout(audioSample.numberOfChannels);
+			this.frame.pts = BigInt(Math.round(audioSample.timestamp * audioSample.sampleRate));
+			this.frame.duration = BigInt(audioSample.numberOfFrames);
+
+			this.frame.allocBuffer();
+			assert(this.frame.data);
+
+			for (let i = 0; i < this.frame.data.length; i++) {
+				audioSample.copyTo(this.frame.data[i]!, { planeIndex: i });
+			}
+		}
+
+		const key = `${this.frame.sampleRate}:${this.frame.channels}:${this.frame.format}`;
+		if (this.inputParametersKey !== null && this.inputParametersKey !== key) {
+			throw new Error(
+				'Input audio parameters changed. For this audio encoder, you cannot change the input audio'
+				+ ' parameters over time.',
+			);
+		}
+		this.inputParametersKey = key;
+
+		// We need the resampler when:
+		// 1. Format conversion is needed (sample format, sample rate, or channel count differs)
+		// 2. The codec requires fixed frame sizes
+		const requiresResampler
+			= this.codecContext.frameSize > 0
+				|| this.codecContext.sampleFormat !== this.frame.format
+				|| this.codecContext.sampleRate !== this.frame.sampleRate
+				|| this.codecContext.channels !== this.frame.channels;
+
+		if (requiresResampler) {
+			if (!this.resampler) {
+				this.resampler = new NodeAv.SoftwareResampleContext();
+				this.resamplerInputSampleRate = this.frame.sampleRate;
+
+				const outLayout = getChannelLayout(this.codecContext.channels);
+				const inLayout = getChannelLayout(this.frame.channels);
+
+				const ret = this.resampler.allocSetOpts2(
+					outLayout, this.codecContext.sampleFormat, this.codecContext.sampleRate,
+					inLayout, this.frame.format as NodeAv.AVSampleFormat, this.frame.sampleRate,
+				);
+				NodeAv.FFmpegError.throwIfError(ret, 'allocSetOpts2');
+
+				const ret2 = this.resampler.init();
+				NodeAv.FFmpegError.throwIfError(ret2, 'init');
+
+				this.dstFrame = new NodeAv.Frame();
+				this.dstFrame.alloc();
+				this.dstFrame.channelLayout = outLayout;
+				this.dstFrame.sampleRate = this.codecContext.sampleRate;
+				this.dstFrame.format = this.codecContext.sampleFormat;
+				this.dstFrame.nbSamples = this.codecContext.frameSize || FRAME_SIZE_FALLBACK;
+				this.dstFrame.duration = BigInt(this.dstFrame.nbSamples);
+				this.dstFrame.allocBuffer();
+
+				this.nextResamplerPts = this.frame.pts;
+			}
+
+			const inputBuffers = this.frame.data;
+			if (!inputBuffers) {
+				throw new DOMException('Frame has no data', 'EncodingError');
+			}
+			await this.resampler.convert(null, 0, inputBuffers, this.frame.nbSamples);
+
+			await this.pullResampledFrames();
+		} else {
+			await this.sendFrameAndReceivePackets(this.frame);
+		}
+	}
+
+	async pullResampledFrames() {
+		assert(this.codecContext);
+		assert(this.resampler);
+		assert(this.dstFrame);
+		assert(this.nextResamplerPts !== null);
+
+		const frameSize = this.codecContext.frameSize || FRAME_SIZE_FALLBACK;
+
+		while (true) {
+			const available = this.resampler.getOutSamples(0);
+			if (available < frameSize) {
+				break;
+			}
+
+			await this.resampler.convert(this.dstFrame.data, frameSize, null, 0);
+
+			this.dstFrame.pts = this.nextResamplerPts;
+
+			await this.sendFrameAndReceivePackets(this.dstFrame);
+			this.nextResamplerPts += BigInt(frameSize);
+		}
+	}
+
+	async sendFrameAndReceivePackets(frame: NodeAv.Frame | null) {
+		assert(this.codecContext);
+
+		const ret = await this.codecContext.sendFrame(frame);
+		NodeAv.FFmpegError.throwIfError(ret, 'Send frame');
+
+		while (true) {
+			const receiveRet = await this.codecContext.receivePacket(this.packet);
+			if (receiveRet === NodeAv.AVERROR_EAGAIN || receiveRet === NodeAv.AVERROR_EOF) {
+				break;
+			}
+
+			this.receivePacket(receiveRet);
+		}
+	}
+
+	receivePacket(ret: number) {
+		assert(this.codecContext);
+		assert(this.firstExpectedTimestamp !== null);
+		NodeAv.FFmpegError.throwIfError(ret, 'Receive packet');
+
+		if (!this.packet.data) {
+			return;
+		}
+
+		let timestamp = Number(this.packet.pts) / this.codecContext.sampleRate;
+		const duration = Number(this.packet.duration) / this.codecContext.sampleRate;
+
+		let data: Uint8Array = this.packet.data;
+
+		let metadata: EncodedAudioChunkMetadata | undefined;
+		if (this.packetEmitted) {
+			metadata = {};
+		} else {
+			// To compensate for any negative timestamp things that FFmpeg might do. It does these for a reason, to
+			// indicate encoder delay, but the notion of this is not yet supported in Mediabunny.
+			this.outputTimestampOffset = this.firstExpectedTimestamp - timestamp;
+
+			const codecString = this.config.codec;
+			let description = this.codecContext.extraData
+				? toUint8Array(this.codecContext.extraData)
+				: undefined;
+
+			if (
+				description
+				// eslint-disable-next-line @stylistic/max-len
+				// eslint-disable-next-line @typescript-eslint/no-explicit-any, @typescript-eslint/no-unsafe-member-access
+				&& this.codec === 'aac' && (this.config as any).aac?.format === 'adts'
+			) {
+				const config = parseAacAudioSpecificConfig(description);
+				this.adtsHeaderTemplate = buildAdtsHeaderTemplate(config);
+				description = undefined; // Not used with 'adts' format
+			}
+
+			if (description && this.codec === 'flac') {
+				// FFmpeg uses the STREAMINFO block as the extradata, but WebCodecs wants a different format:
+				// 1. The bytes 0x66 0x4C 0x61 0x43 ("fLaC" in ASCII)
+				// 2. A metadata block (called the STREAMINFO block) as described in section 7 of [FLAC]
+				// 3. Other optional metadata blocks (not included here, because, well, they're optional)
+				description = new Uint8Array([
+					0x66, 0x4c, 0x61, 0x43, // 'fLaC'
+					128, 0, 0, description.byteLength,
+					...description,
+				]);
+			}
+
+			metadata = {
+				decoderConfig: {
+					codec: codecString,
+					sampleRate: this.codecContext.sampleRate,
+					numberOfChannels: this.codecContext.channels,
+					description,
+				},
+			};
+		}
+
+		if (this.adtsHeaderTemplate) {
+			const frameLength = data.byteLength + this.adtsHeaderTemplate.header.byteLength;
+			this.adtsHeaderTemplate.bitstream.pos = 30;
+			this.adtsHeaderTemplate.bitstream.writeBits(13, frameLength);
+
+			const final = new Uint8Array(this.adtsHeaderTemplate.header.byteLength + data.byteLength);
+			final.set(this.adtsHeaderTemplate.header, 0);
+			final.set(data, this.adtsHeaderTemplate.header.byteLength);
+
+			data = final;
+		}
+
+		timestamp += this.outputTimestampOffset;
+
+		const packet = new EncodedPacket(
+			data,
+			'key',
+			timestamp,
+			duration,
+		);
+
+		this.onPacket(packet, metadata);
+		this.packetEmitted = true;
+	}
+
+	async flush(): Promise<void> {
+		if (!this.codecContext) {
+			return;
+		}
+
+		outer:
+		if (this.resampler) {
+			assert(this.resamplerInputSampleRate !== null);
+
+			const currentOutSamples = this.resampler.getOutSamples(0);
+			if (currentOutSamples === 0) {
+				break outer; // Clean cut-off point
+			}
+
+			const frameSize = this.codecContext.frameSize || FRAME_SIZE_FALLBACK;
+			assert(currentOutSamples < frameSize); // Because if it's more, it would've already been retrieved
+
+			const inputSamplesNeeded = Math.ceil(
+				((frameSize - currentOutSamples) / this.codecContext.sampleRate) * this.resamplerInputSampleRate,
+			);
+			this.resampler.injectSilence(inputSamplesNeeded);
+
+			await this.pullResampledFrames();
+		}
+
+		await this.sendFrameAndReceivePackets(null);
+
+		this.codecContext.freeContext();
+		this.codecContext = null;
+		this.packetEmitted = false;
+		this.firstExpectedTimestamp = null;
+		this.outputTimestampOffset = 0;
+
+		this.resampler?.free();
+		this.resampler = null;
+		this.inputParametersKey = null;
+		this.resamplerInputSampleRate = null;
+		this.nextResamplerPts = null;
+		this.dstFrame?.free();
+		this.dstFrame = null;
+	}
+
+	close(): MaybePromise<void> {
+		this.codecContext?.freeContext();
+		this.frame.free();
+		this.packet.free();
+		this.dstFrame?.free();
+		this.resampler?.free();
+	}
+}

packages/server/src/audio-sample.ts

@@ -0,0 +1,55 @@
+import { AudioSampleResource } from 'mediabunny';
+import * as NodeAv from 'node-av';
+import { toAudioSampleFormat } from './misc';
+import { assert, toUint8Array } from '../../../src/misc';
+
+export class NodeAvFrameAudioSampleResource extends AudioSampleResource {
+	frame: NodeAv.Frame;
+	timestamp: number;
+
+	constructor(frame: NodeAv.Frame, timestamp: number) {
+		super();
+
+		const clone = frame.clone();
+		if (!clone) {
+			throw new Error('Allocation failure during frame clone.');
+		}
+
+		this.frame = clone;
+		this.timestamp = timestamp;
+	}
+
+	getFormat(): AudioSampleFormat {
+		const result = toAudioSampleFormat(this.frame.format as NodeAv.AVSampleFormat);
+		if (result === null) {
+			throw new TypeError('Unsupported audio sample format: ' + this.frame.format);
+		}
+
+		return result;
+	}
+
+	getSampleRate(): number {
+		return this.frame.sampleRate;
+	}
+
+	getNumberOfChannels(): number {
+		return this.frame.channels;
+	}
+
+	getNumberOfFrames(): number {
+		return this.frame.nbSamples;
+	}
+
+	getTimestamp(): number {
+		return this.timestamp;
+	}
+
+	close(): void {
+		this.frame.free();
+	}
+
+	getDataPlane(planeIndex: number): Uint8Array {
+		assert(this.frame.data && planeIndex < this.frame.data.length);
+		return toUint8Array(this.frame.data[planeIndex]!);
+	}
+}

packages/server/src/index.ts

@@ -1,7 +1,9 @@
 import { registerDecoder, registerEncoder } from 'mediabunny';
-import { NodeAvVideoDecoder } from './video-decoder';
 import * as NodeAv from 'node-av';
+import { NodeAvVideoDecoder } from './video-decoder';
 import { NodeAvVideoEncoder } from './video-encoder';
+import { NodeAvAudioDecoder } from './audio-decoder';
+import { NodeAvAudioEncoder } from './audio-encoder';
 
 const SERVER_LOADED_SYMBOL = Symbol.for('@mediabunny/server loaded');
 if ((globalThis as Record<symbol, unknown>)[SERVER_LOADED_SYMBOL]) {
@@ -23,6 +25,11 @@ export const registerMediabunnyServer = () => {
 
 	NodeAv.Log.setLevel(NodeAv.AV_LOG_ERROR);
 
+	// Video
 	registerDecoder(NodeAvVideoDecoder);
 	registerEncoder(NodeAvVideoEncoder);
+
+	// Audio
+	registerDecoder(NodeAvAudioDecoder);
+	registerEncoder(NodeAvAudioEncoder);
 };

packages/server/src/misc.ts

@@ -9,6 +9,12 @@ export const CODEC_TO_CODEC_ID: Partial<Record<MediaCodec, NodeAv.AVCodecID>> =
 	av1: NodeAv.AV_CODEC_ID_AV1,
 
 	aac: NodeAv.AV_CODEC_ID_AAC,
+	opus: NodeAv.AV_CODEC_ID_OPUS,
+	mp3: NodeAv.AV_CODEC_ID_MP3,
+	vorbis: NodeAv.AV_CODEC_ID_VORBIS,
+	flac: NodeAv.AV_CODEC_ID_FLAC,
+	ac3: NodeAv.AV_CODEC_ID_AC3,
+	eac3: NodeAv.AV_CODEC_ID_EAC3,
 };
 
 let cachedHardwareContext: NodeAv.HardwareContext | null | undefined = undefined;

packages/server/src/video-encoder.ts

@@ -165,10 +165,8 @@ export class NodeAvVideoEncoder extends CustomVideoEncoder {
 			assert(this.codecContext);
 		}
 
-		const underlyingData = videoSample.getUnderlyingData();
-
-		if (underlyingData instanceof NodeAvFrameVideoSampleResource) {
-			this.frame.ref(underlyingData.frame);
+		if (videoSample._data instanceof NodeAvFrameVideoSampleResource) {
+			this.frame.ref(videoSample._data.frame);
 		} else {
 			if (videoSample.format === null) {
 				throw new Error('Cannot encode foreign VideoSample with unknown (null) format.');

src/sample.ts

@@ -615,15 +615,6 @@ export class VideoSample implements Disposable {
 		finalizationRegistry?.register(this, { type: 'video', data: this._data }, this);
 	}
 
-	getUnderlyingData() {
-		if (this._closed) {
-			throw new Error('VideoSample is closed.');
-		}
-
-		assert(this._data !== null);
-		return this._data;
-	}
-
 	/** Clones this video sample. */
 	clone() {
 		if (this._closed) {
@@ -1881,15 +1872,7 @@ export abstract class AudioSampleResource {
 	 */
 	abstract close(): void;
 
-	/**
-	 * Returns the number of bytes required to hold the underlying audio data as specified by the given options.
-	 */
-	abstract allocationSize(options: AudioSampleCopyToOptions): number;
-
-	/**
-	 * Copies the underlying audio data to an ArrayBuffer or ArrayBufferView as specified by the given options.
-	 */
-	abstract copyTo(destination: AllowSharedBufferSource, options: AudioSampleCopyToOptions): void;
+	abstract getDataPlane(planeIndex: number): Uint8Array;
 }
 
 /**
@@ -2004,10 +1987,30 @@ export class AudioSample implements Disposable {
 			init._referenceCount++;
 
 			this.format = init.getFormat();
+			if (!AUDIO_SAMPLE_FORMATS.has(this.format)) {
+				throw new TypeError('getFormat() must return an AudioSampleFormat.');
+			}
+
 			this.sampleRate = init.getSampleRate();
+			if (!Number.isInteger(this.sampleRate) || this.sampleRate <= 0) {
+				throw new TypeError('getSampleRate() must return a positive integer.');
+			}
+
 			this.numberOfFrames = init.getNumberOfFrames();
+			if (!Number.isInteger(this.numberOfFrames) || this.numberOfFrames < 0) {
+				throw new TypeError('getNumberOfFrames() must return a non-negative integer.');
+			}
+
 			this.numberOfChannels = init.getNumberOfChannels();
+			if (!Number.isInteger(this.numberOfChannels) || this.numberOfChannels <= 0) {
+				throw new TypeError('getNumberOfChannels() must return a positive integer.');
+			}
+
 			this.timestamp = init.getTimestamp();
+			if (!Number.isFinite(this.timestamp)) {
+				throw new TypeError('getTimestamp() must return a finite number.');
+			}
+
 			this.duration = this.numberOfFrames / this.sampleRate;
 		} else {
 			if (!init || typeof init !== 'object') {
@@ -2084,10 +2087,6 @@ export class AudioSample implements Disposable {
 			throw new Error('AudioSample is closed.');
 		}
 
-		if (this._data instanceof AudioSampleResource) {
-			return this._data.allocationSize(options);
-		}
-
 		const destFormat = options.format ?? this.format;
 
 		const frameOffset = options.frameOffset ?? 0;
@@ -2140,11 +2139,8 @@ export class AudioSample implements Disposable {
 			throw new Error('AudioSample is closed.');
 		}
 
-		if (this._data instanceof AudioSampleResource) {
-			return this._data.copyTo(destination, options);
-		}
-
-		const { planeIndex, format, frameCount: optFrameCount, frameOffset: optFrameOffset } = options;
+		const { format, frameCount: optFrameCount, frameOffset: optFrameOffset } = options;
+		let { planeIndex } = options;
 
 		const srcFormat = this.format;
 		const destFormat = format ?? this.format;
@@ -2204,12 +2200,51 @@ export class AudioSample implements Disposable {
 				});
 			}
 		} else {
-			const uint8Data = this._data;
-			const srcView = toDataView(uint8Data);
 			const readFn = getReadFunction(srcFormat);
 			const srcBytesPerSample = getBytesPerSample(srcFormat);
 			const srcIsPlanar = formatIsPlanar(srcFormat);
 
+			let uint8Data: Uint8Array;
+			if (this._data instanceof AudioSampleResource) {
+				const getDataPlaneValidated = (index: number) => {
+					const result = (this._data as AudioSampleResource).getDataPlane(index);
+					if (!(result instanceof Uint8Array)) {
+						throw new TypeError('getDataPlane() must return a Uint8Array.');
+					}
+
+					const expectedSize = numFrames * srcBytesPerSample * (srcIsPlanar ? 1 : numChannels);
+					if (result.byteLength !== expectedSize) {
+						throw new TypeError(
+							`Data plane ${index} has invalid size. Expected exactly ${expectedSize} bytes, got`
+							+ ` ${result.byteLength} bytes.`,
+						);
+					}
+
+					return result;
+				};
+
+				if (srcIsPlanar) {
+					if (destIsPlanar) {
+						// Only one source plane will be extracted, so let's fetch only that one
+						uint8Data = getDataPlaneValidated(planeIndex);
+						planeIndex = 0; // To fix the subsequent access
+					} else {
+						// Pack all planes tightly together
+						uint8Data = new Uint8Array(numFrames * srcBytesPerSample * numChannels);
+						for (let ch = 0; ch < numChannels; ch++) {
+							const planeData = getDataPlaneValidated(ch);
+							uint8Data.set(planeData, ch * numFrames * srcBytesPerSample);
+						}
+					}
+				} else {
+					uint8Data = getDataPlaneValidated(0); // That's the only plane there is
+				}
+			} else {
+				uint8Data = this._data;
+			}
+
+			const srcView = toDataView(uint8Data);
+
 			for (let i = 0; i < copyFrameCount; i++) {
 				if (destIsPlanar) {
 					const destOffset = i * destBytesPerSample;

test/node/server-extension.test.ts

@@ -3,13 +3,14 @@ import { registerMediabunnyServer } from '@mediabunny/server';
 import { Input } from '../../src/input.js';
 import { BufferSource, FilePathSource } from '../../src/source.js';
 import { ALL_FORMATS } from '../../src/input-format.js';
-import { assert, toUint8Array } from '../../src/misc.js';
-import { EncodedPacketSink, VideoSampleSink } from '../../src/media-sink.js';
+import { assert, last, toUint8Array } from '../../src/misc.js';
+import { AudioSampleSink, EncodedPacketSink, VideoSampleSink } from '../../src/media-sink.js';
 import { NodeAvVideoDecoder } from '../../packages/server/src/video-decoder.js';
 import { NodeAvVideoEncoder } from '../../packages/server/src/video-encoder.js';
 import { NodeAvAudioDecoder } from '../../packages/server/src/audio-decoder.js';
+import { NodeAvAudioEncoder } from '../../packages/server/src/audio-encoder.js';
 import { AudioSample, VideoSample } from '../../src/sample.js';
-import { buildVideoCodecString, VideoCodec } from '../../src/codec.js';
+import { AudioCodec, buildAudioCodecString, buildVideoCodecString, VideoCodec } from '../../src/codec.js';
 import { EncodedPacket } from '../../src/packet.js';
 import {
 	AvcNalUnitType,
@@ -24,6 +25,7 @@ import { Mp4OutputFormat } from '../../src/output-format.js';
 import { BufferTarget } from '../../src/target.js';
 import { Conversion } from '../../src/conversion.js';
 import { NodeAvFrameVideoSampleResource } from '../../packages/server/src/video-sample.js';
+import { NodeAvFrameAudioSampleResource } from '../../packages/server/src/audio-sample.js';
 
 beforeAll(() => {
 	registerMediabunnyServer();
@@ -600,7 +602,7 @@ describe('Video', async () => {
 		using sample = await sink.getSample(0);
 		assert(sample);
 
-		expect(sample.getUnderlyingData()).toBeInstanceOf(NodeAvFrameVideoSampleResource);
+		expect(sample._data).toBeInstanceOf(NodeAvFrameVideoSampleResource);
 		expect(sample.format).toBe('I420');
 		expect(sample.codedWidth).toBe(1920);
 		expect(sample.codedHeight).toBe(1080);
@@ -736,7 +738,6 @@ describe('Video', async () => {
 	});
 });
 
-/*
 describe('Audio', async () => {
 	test('Decoder lifecycle', async () => {
 		using input = new Input({
@@ -807,5 +808,515 @@ describe('Audio', async () => {
 
 		await decoder.close();
 	});
+
+	test('Encoder lifecycle', async () => {
+		const encoder = new NodeAvAudioEncoder();
+		// @ts-expect-error Readonly
+		encoder.codec = 'aac';
+		// @ts-expect-error Readonly
+		encoder.config = {
+			codec: buildAudioCodecString('aac', 2, 48000),
+			numberOfChannels: 2,
+			sampleRate: 48000,
+			bitrate: 128000,
+		} satisfies AudioEncoderConfig;
+
+		let packetCount = 0;
+
+		// @ts-expect-error Readonly
+		encoder.onPacket = (packet: EncodedPacket, meta: EncodedAudioChunkMetadata) => {
+			expect(packet.duration).toBe(1024 / 48000);
+			expect(packet.type).toBe('key');
+
+			if (packetCount === 0) {
+				expect(packet.timestamp).toBe(0);
+
+				expect(meta.decoderConfig).toBeDefined();
+				expect(meta.decoderConfig!.codec).toBe('mp4a.40.2');
+				expect(meta.decoderConfig!.numberOfChannels).toBe(2);
+				expect(meta.decoderConfig!.sampleRate).toBe(48000);
+				expect(meta.decoderConfig?.description).toBeDefined();
+			}
+
+			packetCount++;
+		};
+
+		await encoder.init();
+
+		const data = createF32SineWave(48000, 2, 2);
+		using sample1 = new AudioSample({
+			data,
+			format: 'f32',
+			timestamp: 0,
+			numberOfChannels: 2,
+			sampleRate: 48000,
+		});
+		await encoder.encode(sample1);
+
+		await encoder.flush();
+
+		const minPacketCount = 2 * 48000 / 1024;
+		expect(packetCount).toBeGreaterThan(minPacketCount);
+
+		packetCount = 0;
+
+		using sample2 = new AudioSample({
+			data,
+			format: 'f32',
+			timestamp: 0,
+			numberOfChannels: 2,
+			sampleRate: 48000,
+		});
+		await encoder.encode(sample2);
+
+		await encoder.flush();
+
+		expect(packetCount).toBeGreaterThan(minPacketCount);
+
+		await encoder.close();
+	});
+
+	const createF32SineWave = (sampleRate: number, channels: number, durationSeconds: number) => {
+		const totalFrames = sampleRate * durationSeconds;
+		const data = new Float32Array(totalFrames * channels);
+
+		for (let i = 0; i < totalFrames; i++) {
+			const value = Math.sin(2 * Math.PI * 440 * i / sampleRate);
+			for (let ch = 0; ch < channels; ch++) {
+				data[i * channels + ch] = value;
+			}
+		}
+
+		return data;
+	};
+
+	test('AAC encode & decode, AAC format', async () => {
+		await encodeDecodeTest('aac', {
+			// @ts-expect-error Fucky type
+			aac: { format: 'aac' },
+		}, async (packet, meta, i) => {
+			expect(packet.type).toBe('key');
+			expect(packet.duration).toBe(1024 / 48000);
+
+			if (i === 0) {
+				expect(meta.decoderConfig).toBeDefined();
+				expect(meta.decoderConfig!.codec).toBe('mp4a.40.2');
+				expect(meta.decoderConfig!.numberOfChannels).toBe(2);
+				expect(meta.decoderConfig!.sampleRate).toBe(48000);
+				expect(meta.decoderConfig!.description).toBeDefined();
+			}
+		}, async (sample) => {
+			expect(sample.duration).toBe(1024 / 48000);
+			expect(sample.numberOfChannels).toBe(2);
+			expect(sample.sampleRate).toBe(48000);
+		});
+	});
+
+	test('AAC encode & decode, ADTS format', async () => {
+		await encodeDecodeTest('aac', {
+			// @ts-expect-error Fucky type
+			aac: { format: 'adts' },
+		}, async (packet, meta, i) => {
+			expect(packet.type).toBe('key');
+			expect(packet.duration).toBe(1024 / 48000);
+			expect(packet.data[0]).toBe(0xff);
+
+			if (i === 0) {
+				expect(meta.decoderConfig).toBeDefined();
+				expect(meta.decoderConfig!.codec).toBe('mp4a.40.2');
+				expect(meta.decoderConfig!.numberOfChannels).toBe(2);
+				expect(meta.decoderConfig!.sampleRate).toBe(48000);
+				expect(meta.decoderConfig!.description).toBeUndefined();
+			}
+		}, async (sample) => {
+			expect(sample.duration).toBe(1024 / 48000);
+			expect(sample.numberOfChannels).toBe(2);
+			expect(sample.sampleRate).toBe(48000);
+		});
+	});
+
+	test('Opus encode & decode', async () => {
+		await encodeDecodeTest('opus', {}, async (packet, meta, i, n) => {
+			expect(packet.type).toBe('key');
+
+			if (i < n - 1) {
+				expect(packet.duration).toBe(0.02);
+			}
+
+			if (i === 0) {
+				expect(meta.decoderConfig).toBeDefined();
+				expect(meta.decoderConfig!.codec).toBe('opus');
+				expect(meta.decoderConfig!.numberOfChannels).toBe(2);
+				expect(meta.decoderConfig!.sampleRate).toBe(48000);
+				expect(meta.decoderConfig!.description).toBeDefined();
+				expect([...toUint8Array(meta.decoderConfig!.description!).slice(0, 8)]).toEqual([
+					// OpusHead
+					0x4f, 0x70, 0x75, 0x73, 0x48, 0x65, 0x61, 0x64,
+				]);
+			}
+		}, async (sample, i, n) => {
+			expect(sample.numberOfChannels).toBe(2);
+			expect(sample.sampleRate).toBe(48000);
+
+			if (i > 0 && i < n - 1) {
+				expect(sample.duration).toBe(0.02);
+			}
+		});
+	});
+
+	test('MP3 encode & decode', async () => {
+		await encodeDecodeTest('mp3', {}, async (packet, meta, i, n) => {
+			expect(packet.type).toBe('key');
+
+			if (i < n - 1) {
+				expect(packet.duration).toBe(1152 / 48000);
+			}
+
+			if (i === 0) {
+				expect(meta.decoderConfig).toBeDefined();
+				expect(meta.decoderConfig!.codec).toBe('mp3');
+				expect(meta.decoderConfig!.numberOfChannels).toBe(2);
+				expect(meta.decoderConfig!.sampleRate).toBe(48000);
+				expect(meta.decoderConfig!.description).toBeUndefined();
+			}
+		}, async (sample) => {
+			expect(sample.numberOfChannels).toBe(2);
+			expect(sample.sampleRate).toBe(48000);
+			expect(sample.duration).toBe(1152 / 48000);
+		});
+	});
+
+	test('Vorbis encode & decode', async () => {
+		await encodeDecodeTest('vorbis', {}, async (packet, meta, i) => {
+			expect(packet.type).toBe('key');
+
+			if (i === 0) {
+				expect(meta.decoderConfig).toBeDefined();
+				expect(meta.decoderConfig!.codec).toBe('vorbis');
+				expect(meta.decoderConfig!.numberOfChannels).toBe(2);
+				expect(meta.decoderConfig!.sampleRate).toBe(48000);
+				expect(meta.decoderConfig!.description).toBeDefined();
+				expect(toUint8Array(meta.decoderConfig!.description!)[0]).toBe(2); // "Xiph extradata format"
+			}
+		}, async (sample) => {
+			expect(sample.numberOfChannels).toBe(2);
+			expect(sample.sampleRate).toBe(48000);
+		});
+	});
+
+	test('FLAC encode & decode', async () => {
+		await encodeDecodeTest('flac', {}, async (packet, meta, i) => {
+			expect(packet.type).toBe('key');
+			expect(packet.duration).toBe(0.096);
+
+			if (i === 0) {
+				expect(meta.decoderConfig).toBeDefined();
+				expect(meta.decoderConfig!.codec).toBe('flac');
+				expect(meta.decoderConfig!.numberOfChannels).toBe(2);
+				expect(meta.decoderConfig!.sampleRate).toBe(48000);
+				expect(meta.decoderConfig!.description).toBeDefined();
+				expect([...toUint8Array(meta.decoderConfig!.description!).slice(0, 4)]).toEqual([
+					// fLaC
+					0x66, 0x4c, 0x61, 0x43,
+				]);
+			}
+		}, async (sample) => {
+			expect(sample.numberOfChannels).toBe(2);
+			expect(sample.sampleRate).toBe(48000);
+			expect(sample.duration).toBe(0.096);
+		});
+	});
+
+	test('AC-3 encode & decode', async () => {
+		await encodeDecodeTest('ac3', {}, async (packet, meta, i) => {
+			expect(packet.type).toBe('key');
+			expect(packet.duration).toBe(0.032);
+
+			if (i === 0) {
+				expect(meta.decoderConfig).toBeDefined();
+				expect(meta.decoderConfig!.codec).toBe('ac-3');
+				expect(meta.decoderConfig!.numberOfChannels).toBe(2);
+				expect(meta.decoderConfig!.sampleRate).toBe(48000);
+				expect(meta.decoderConfig!.description).toBeUndefined();
+			}
+		}, async (sample) => {
+			expect(sample.numberOfChannels).toBe(2);
+			expect(sample.sampleRate).toBe(48000);
+			expect(sample.duration).toBe(0.032);
+		});
+	});
+
+	test('E-AC-3 encode & decode', async () => {
+		await encodeDecodeTest('eac3', {}, async (packet, meta, i) => {
+			expect(packet.type).toBe('key');
+			expect(packet.duration).toBe(0.032);
+
+			if (i === 0) {
+				expect(meta.decoderConfig).toBeDefined();
+				expect(meta.decoderConfig!.codec).toBe('ec-3');
+				expect(meta.decoderConfig!.numberOfChannels).toBe(2);
+				expect(meta.decoderConfig!.sampleRate).toBe(48000);
+				expect(meta.decoderConfig!.description).toBeUndefined();
+			}
+		}, async (sample) => {
+			expect(sample.numberOfChannels).toBe(2);
+			expect(sample.sampleRate).toBe(48000);
+			expect(sample.duration).toBe(0.032);
+		});
+	});
+
+	const encodeDecodeTest = async (
+		codec: AudioCodec,
+		extraConfig: Partial<AudioEncoderConfig>,
+		onPacket: (packet: EncodedPacket, meta: EncodedAudioChunkMetadata, i: number, n: number) => Promise<void>,
+		onSample: (sample: AudioSample, i: number, n: number) => Promise<void>,
+	) => {
+		const sampleRate = 48000;
+		const numberOfChannels = 2;
+
+		const encoder = new NodeAvAudioEncoder();
+		// @ts-expect-error Readonly
+		encoder.codec = codec;
+		// @ts-expect-error Readonly
+		encoder.config = {
+			codec: buildAudioCodecString(codec, numberOfChannels, sampleRate),
+			numberOfChannels,
+			sampleRate,
+			bitrate: 128000,
+			...extraConfig,
+		} satisfies AudioEncoderConfig;
+
+		const packets: EncodedPacket[] = [];
+		const metas: EncodedAudioChunkMetadata[] = [];
+
+		// @ts-expect-error Readonly
+		encoder.onPacket = (packet: EncodedPacket, meta: EncodedAudioChunkMetadata) => {
+			packets.push(packet);
+			metas.push(meta);
+		};
+
+		await encoder.init();
+
+		const data = createF32SineWave(sampleRate, numberOfChannels, 2);
+		using inputSample = new AudioSample({
+			data,
+			format: 'f32',
+			timestamp: 0,
+			numberOfChannels,
+			sampleRate,
+		});
+		await encoder.encode(inputSample);
+
+		await encoder.flush();
+
+		for (let i = 0; i < packets.length; i++) {
+			await onPacket(packets[i]!, metas[i]!, i, packets.length);
+		}
+
+		const decoder = new NodeAvAudioDecoder();
+		// @ts-expect-error Readonly
+		decoder.codec = codec;
+		// @ts-expect-error Readonly
+		decoder.config = metas[0]!.decoderConfig!;
+
+		const decodedSamples: AudioSample[] = [];
+
+		// @ts-expect-error Readonly
+		decoder.onSample = (sample: AudioSample) => {
+			decodedSamples.push(sample);
+		};
+
+		await decoder.init();
+
+		for (const packet of packets) {
+			await decoder.decode(packet);
+		}
+
+		await decoder.flush();
+
+		expect(decodedSamples.length).toBeGreaterThan(0);
+		expect(last(decodedSamples)!.timestamp + last(decodedSamples)!.duration).toBeGreaterThanOrEqual(2);
+
+		for (let i = 0; i < decodedSamples.length; i++) {
+			await onSample(decodedSamples[i]!, i, decodedSamples.length);
+		}
+
+		const signalChunks: Float32Array[] = [];
+
+		for (const sample of decodedSamples) {
+			const buf = new Float32Array(new ArrayBuffer(sample.allocationSize({
+				format: 'f32-planar', planeIndex: 0,
+			})));
+			sample.copyTo(buf, { format: 'f32-planar', planeIndex: 0 });
+			signalChunks.push(buf);
+
+			sample.close();
+		}
+
+		const totalSize = signalChunks.reduce((sum, chunk) => sum + chunk.length, 0);
+		const signal = new Float32Array(totalSize);
+		let offset = 0;
+		for (const chunk of signalChunks) {
+			signal.set(chunk, offset);
+			offset += chunk.length;
+		}
+
+		const score = sine440Score(signal, sampleRate, 440);
+		expect(score).toBeGreaterThan(0.98);
+
+		await encoder.close();
+		await decoder.close();
+	};
+
+	const sine440Score = (x: Float32Array, sampleRate: number, freq: number) => {
+		const w = 2 * Math.PI * freq / sampleRate;
+
+		let ss = 0, cc = 0, sc = 0;
+		let xs = 0, xc = 0;
+		let xx = 0;
+
+		for (let n = 0; n < x.length; n++) {
+			const s = Math.sin(w * n);
+			const c = Math.cos(w * n);
+
+			ss += s * s;
+			cc += c * c;
+			sc += s * c;
+
+			xs += x[n]! * s;
+			xc += x[n]! * c;
+			xx += x[n]! * x[n]!;
+		}
+
+		const det = ss * cc - sc * sc;
+
+		const a = (xs * cc - xc * sc) / det;
+		const b = (xc * ss - xs * sc) / det;
+
+		let fitEnergy = 0;
+
+		for (let n = 0; n < x.length; n++) {
+			const y = a * Math.sin(w * n) + b * Math.cos(w * n);
+			fitEnergy += y * y;
+		}
+
+		const score = fitEnergy / xx;
+		return score;
+	};
+
+	test('AAC conversion roundtrip', { timeout: 10_000 }, async () => {
+		await conversionRoundtrip('aac');
+	});
+
+	test('Opus conversion roundtrip', { timeout: 10_000 }, async () => {
+		await conversionRoundtrip('opus');
+	});
+
+	test('MP3 conversion roundtrip', { timeout: 10_000 }, async () => {
+		await conversionRoundtrip('mp3');
+	});
+
+	test('Vorbis conversion roundtrip', { timeout: 10_000 }, async () => {
+		await conversionRoundtrip('vorbis');
+	});
+
+	test('FLAC conversion roundtrip', { timeout: 10_000 }, async () => {
+		await conversionRoundtrip('flac');
+	});
+
+	test('AC-3 conversion roundtrip', { timeout: 10_000 }, async () => {
+		await conversionRoundtrip('ac3');
+	});
+
+	test('E-AC-3 conversion roundtrip', { timeout: 10_000 }, async () => {
+		await conversionRoundtrip('eac3');
+	});
+
+	const conversionRoundtrip = async (codec: AudioCodec) => {
+		using input = new Input({
+			source: new FilePathSource('./test/public/trim-buck-bunny-ffmpeg.ts'),
+			formats: ALL_FORMATS,
+		});
+
+		const output = new Output({
+			format: new Mp4OutputFormat(),
+			target: new BufferTarget(),
+		});
+
+		const inputTrack = await input.getPrimaryAudioTrack();
+		assert(inputTrack);
+
+		const conversion = await Conversion.init({
+			input,
+			output,
+			video: {
+				discard: true,
+			}, audio: {
+				codec,
+				forceTranscode: true,
+			},
+			trim: {
+				start: 0,
+			},
+		});
+		await conversion.execute();
+
+		using newInput = new Input({
+			source: new BufferSource(output.target.buffer!),
+			formats: ALL_FORMATS,
+		});
+
+		const newInputTrack = await newInput.getPrimaryAudioTrack();
+		assert(newInputTrack);
+
+		expect(await newInputTrack.getCodec()).toBe(codec);
+		expect(await newInputTrack.computeDuration()).toBeCloseTo(await inputTrack.computeDuration(), 0);
+
+		const sink = new AudioSampleSink(newInputTrack);
+
+		let sampleCount = 0;
+		for await (using sample of sink.samples()) {
+			expect([await inputTrack.getNumberOfChannels(), 2].includes(sample.numberOfChannels)).toBe(true);
+			expect(sample.sampleRate).toBe(await inputTrack.getSampleRate());
+
+			sampleCount++;
+		}
+
+		expect(sampleCount).toBeGreaterThan(0);
+	};
+
+	test('Custom AudioSample resource', async () => {
+		using input = new Input({
+			source: new FilePathSource('./test/public/trim-buck-bunny-ffmpeg.ts'),
+			formats: ALL_FORMATS,
+		});
+
+		const audioTrack = await input.getPrimaryAudioTrack();
+		assert(audioTrack);
+
+		const sink = new AudioSampleSink(audioTrack);
+		using sample = await sink.getSample(await audioTrack.getFirstTimestamp());
+		assert(sample);
+
+		expect(sample._data).toBeInstanceOf(NodeAvFrameAudioSampleResource);
+		expect(sample.format).toBe('f32-planar');
+		expect(sample.numberOfChannels).toBe(6);
+		expect(sample.sampleRate).toBe(48000);
+		expect(sample.timestamp).toBe(await audioTrack.getFirstTimestamp());
+		expect(sample.duration).toBe(1024 / 48000);
+		expect(sample.numberOfFrames).toBe(1024);
+
+		const size = sample.allocationSize({ planeIndex: 0 });
+		expect(size).toBe(1024 * Float32Array.BYTES_PER_ELEMENT);
+
+		// Test a bunch of copyTo()s:
+		const buf = new ArrayBuffer(1e6);
+		sample.copyTo(buf, { planeIndex: 0 });
+		sample.copyTo(buf, { planeIndex: 1 });
+		sample.copyTo(buf, { planeIndex: 2 });
+		sample.copyTo(buf, { planeIndex: 3 });
+		sample.copyTo(buf, { planeIndex: 4 });
+		sample.copyTo(buf, { planeIndex: 5 });
+		sample.copyTo(buf, { format: 'f32', planeIndex: 0 });
+	});
 });
-*/