Decrease AudioBuffer chunking size, support more MP3 sample rates, lift MP3 encoder memory limit

Fix UrlSource single-byte buffer on Range Request HTTP 200

dev/convert.html

@@ -24,7 +24,7 @@
 			chunked: true,
 			chunkSize: 2**20
 		});
-		const outputFormat = new Mediabunny.Mp4OutputFormat({});
+		const outputFormat = new Mediabunny.Mp3OutputFormat({});
 
 		const button = document.createElement('button');
 		button.textContent = 'Cancel';
@@ -41,7 +41,7 @@
 				target
 			}),
 			audio: {
-				discard: true,
+				//discard: true,
 				//codec: 'opus',
 				//bitrate: 128000,
 				//numberOfChannels: 1,
@@ -94,8 +94,8 @@
 				//height: 100,
 			}),
 			trim: {
-				start: 0,
-				end: 20
+				//start: 0,
+				//end: 20
 			},
 		});
 		console.log(conversion);

docs/guide/media-sources.md

@@ -123,6 +123,7 @@ const sampleSource = new VideoSampleSource({
 });
 
 await sampleSource.add(videoSample);
+videoSample.close(); // If it's not needed anymore
 
 // You may optionally force samples to be encoded as key frames:
 await sampleSource.add(videoSample, { keyFrame: true });
@@ -285,6 +286,7 @@ const sampleSource = new AudioSampleSource({
 });
 
 await sampleSource.add(audioSample);
+audioSample.close(); // If it's not needed anymore
 ```
 
 ### `AudioBufferSource`

docs/index.md

@@ -94,6 +94,7 @@ const sponsors = {
 	],
 	individual: [
 		{ image: 'https://avatars.githubusercontent.com/u/84167135', name: 'Memenome', url: 'https://github.com/memenome' },
+		{ image: 'https://avatars.githubusercontent.com/u/5913254', name: 'Brandon McConnell', url: 'https://github.com/brandonmcconnell' },
 		{ image: 'https://avatars.githubusercontent.com/u/9549394', name: 'studnitz', url: 'https://github.com/studnitz' },
 		{ image: 'https://avatars.githubusercontent.com/u/30229596', name: 'Pablo Bonilla', url: 'https://github.com/devPablo' },
 		{ image: 'https://avatars.githubusercontent.com/u/58149663', name: 'H7GhosT', url: 'https://github.com/H7GhosT' },
@@ -339,7 +340,7 @@ await conversion.execute();
 		<div class="flex flex-wrap mt-1 justify-center">
 			<a v-for="sponsor in sponsors.individual" :href="sponsor.url" target="_blank" class="flex gap-1 w-24 flex-col items-center p-2 rounded-xl hover:bg-(--vp-c-gray-3) !text-(--vp-c-text-1) !no-underline">
 				<img :src="sponsor.image" class="size-8 rounded-full">
-				<p class="!my-0 !font-medium text-xs !leading-4">{{ sponsor.name }}</p>
+				<p class="!my-0 !font-medium text-xs !leading-4 text-center">{{ sponsor.name }}</p>
 			</a>
 		</div>
 	</template>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "mediabunny",
-  "version": "1.7.2",
+  "version": "1.8.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "mediabunny",
-      "version": "1.7.2",
+      "version": "1.8.0",
       "license": "MPL-2.0",
       "workspaces": [
         "packages/*"
@@ -5900,9 +5900,9 @@
       }
     },
     "node_modules/mediabunny": {
-      "version": "1.7.1",
-      "resolved": "https://registry.npmjs.org/mediabunny/-/mediabunny-1.7.1.tgz",
-      "integrity": "sha512-y9s+Vf6TLhXeVjvlJFSmHRrwUQi2CJCMhxthm6nfhBO1XHJhcOqNOxu4CjhYyjoWgVZB5pkPKyWgZxpPOZfglQ==",
+      "version": "1.7.6",
+      "resolved": "https://registry.npmjs.org/mediabunny/-/mediabunny-1.7.6.tgz",
+      "integrity": "sha512-PtWscl5vdsBYwtNSO0J21lAGUiweudmTmHabz4NWuQ+mAUvtG1ocupyYpT18IflteVtdtNMqxKKPPbvlcHuk0w==",
       "license": "MPL-2.0",
       "peer": true,
       "workspaces": [
@@ -9017,7 +9017,7 @@
     },
     "packages/mp3-encoder": {
       "name": "@mediabunny/mp3-encoder",
-      "version": "1.7.2",
+      "version": "1.8.0",
       "license": "MPL-2.0",
       "devDependencies": {
         "@types/emscripten": "^1.40.1"

package.json

@@ -1,7 +1,7 @@
 {
   "name": "mediabunny",
   "author": "Vanilagy",
-  "version": "1.7.2",
+  "version": "1.8.0",
   "description": "Pure TypeScript media toolkit for reading, writing, and converting media files, directly in the browser.",
   "type": "module",
   "workspaces": [

packages/mp3-encoder/README.md

@@ -108,7 +108,7 @@ For simplicity, all built WASM artifacts are included in the repo, since these r
 
 ### Prerequisites
 
-[Install Emscripten](https://emscripten.org/docs/getting_started/downloads.html). The recommended way is using the emsdk, which involves cloning a repo and running a few commands.
+[Install Emscripten](https://emscripten.org/docs/getting_started/downloads.html). The recommended way is using the emsdk, which involves cloning a repo and running a few commands. The following commands assume Emscripten is sourced in.
 
 ### Compiling LAME:
 
@@ -139,6 +139,7 @@ emcc src/lame-bridge.c build/libmp3lame.a \
     -s MODULARIZE=1 \
     -s EXPORT_ES6=1 \
     -s SINGLE_FILE=1 \
+    -s ALLOW_MEMORY_GROWTH=1 \
     -s ENVIRONMENT=web,worker \
     -s EXPORTED_RUNTIME_METHODS=cwrap,HEAPU8 \
     -s EXPORTED_FUNCTIONS=_malloc,_free \

packages/mp3-encoder/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@mediabunny/mp3-encoder",
   "author": "Vanilagy",
-  "version": "1.7.2",
+  "version": "1.8.0",
   "description": "MP3 encoder extension for Mediabunny, based on LAME.",
   "main": "./dist/bundles/mediabunny-mp3-encoder.mjs",
   "module": "./dist/bundles/mediabunny-mp3-encoder.mjs",

packages/mp3-encoder/src/index.ts

@@ -7,7 +7,7 @@
  */
 
 import { CustomAudioEncoder, AudioCodec, AudioSample, EncodedPacket, registerEncoder } from 'mediabunny';
-import { FRAME_HEADER_SIZE, readFrameHeader } from '../../../shared/mp3-misc';
+import { FRAME_HEADER_SIZE, readFrameHeader, SAMPLING_RATES } from '../../../shared/mp3-misc';
 import type { WorkerCommand, WorkerResponse, WorkerResponseData } from './shared';
 // @ts-expect-error An esbuild plugin handles this, TypeScript doesn't need to understand
 import createWorker from './encode.worker';
@@ -28,7 +28,7 @@ class Mp3Encoder extends CustomAudioEncoder {
 	static override supports(codec: AudioCodec, config: AudioDecoderConfig): boolean {
 		return codec === 'mp3'
 			&& (config.numberOfChannels === 1 || config.numberOfChannels === 2)
-			&& (config.sampleRate === 32000 || config.sampleRate === 44100 || config.sampleRate === 48000);
+			&& Object.values(SAMPLING_RATES).some(x => x.includes(config.sampleRate));
 	}
 
 	async init() {

src/conversion.ts

@@ -671,7 +671,7 @@ export class Conversion {
 						}
 
 						let adjustedSampleTimestamp = Math.max(timestamp - this._startTimestamp, 0);
-						lastCanvasEndTimestamp = timestamp + duration;
+						lastCanvasEndTimestamp = adjustedSampleTimestamp + duration;
 
 						if (frameRate !== undefined) {
 							// Logic for skipping/repeating frames when a frame rate is set
@@ -757,7 +757,7 @@ export class Conversion {
 						}
 
 						let adjustedSampleTimestamp = Math.max(sample.timestamp - this._startTimestamp, 0);
-						lastSampleEndTimestamp = sample.timestamp + sample.duration;
+						lastSampleEndTimestamp = adjustedSampleTimestamp + sample.duration;
 
 						if (frameRate !== undefined) {
 							// Logic for skipping/repeating frames when a frame rate is set

src/input-format.ts

@@ -10,7 +10,7 @@ import { Demuxer } from './demuxer';
 import { Input } from './input';
 import { IsobmffDemuxer } from './isobmff/isobmff-demuxer';
 import { IsobmffReader } from './isobmff/isobmff-reader';
-import { EBMLId, EBMLReader } from './matroska/ebml';
+import { EBMLId, EBMLReader, MIN_HEADER_SIZE } from './matroska/ebml';
 import { MatroskaDemuxer } from './matroska/matroska-demuxer';
 import { Mp3Demuxer } from './mp3/mp3-demuxer';
 import { FRAME_HEADER_SIZE } from '../shared/mp3-misc';
@@ -106,6 +106,10 @@ export class QuickTimeInputFormat extends IsobmffInputFormat {
 	}
 }
 
+function foo() {
+	return 5;
+}
+
 /**
  * Matroska file format.
  * @public
@@ -120,6 +124,12 @@ export class MatroskaInputFormat extends InputFormat {
 
 		const ebmlReader = new EBMLReader(input._mainReader);
 		const varIntSize = ebmlReader.readVarIntSize();
+		if (varIntSize === null) {
+			return false;
+		}
+
+		foo();
+
 		if (varIntSize < 1 || varIntSize > 8) {
 			return false;
 		}
@@ -135,8 +145,11 @@ export class MatroskaInputFormat extends InputFormat {
 		}
 
 		const startPos = ebmlReader.pos;
-		while (ebmlReader.pos < startPos + dataSize) {
-			const { id, size } = ebmlReader.readElementHeader();
+		while (ebmlReader.pos <= startPos + dataSize - MIN_HEADER_SIZE) {
+			const header = ebmlReader.readElementHeader();
+			if (!header) break;
+
+			const { id, size } = header;
 			const dataStartPos = ebmlReader.pos;
 			if (size === null) return false;
 

src/matroska/ebml.ts

@@ -379,7 +379,7 @@ export class EBMLWriter {
 
 const MAX_VAR_INT_SIZE = 8;
 export const MIN_HEADER_SIZE = 2; // 1-byte ID and 1-byte size
-export const MAX_HEADER_SIZE = 4 + MAX_VAR_INT_SIZE; // 4-byte ID and 8-byte size
+export const MAX_HEADER_SIZE = 2 * MAX_VAR_INT_SIZE; // 8-byte ID and 8-byte size
 
 export class EBMLReader {
 	pos = 0;
@@ -411,9 +411,13 @@ export class EBMLReader {
 		const { view, offset } = this.reader.getViewAndOffset(this.pos, this.pos + 1);
 		const firstByte = view.getUint8(offset);
 
+		if (firstByte === 0) {
+			return null; // Invalid VINT
+		}
+
 		let width = 1;
 		let mask = 0x80;
-		while ((firstByte & mask) === 0 && width < 8) {
+		while ((firstByte & mask) === 0) {
 			width++;
 			mask >>= 1;
 		}
@@ -426,10 +430,14 @@ export class EBMLReader {
 		const { view, offset } = this.reader.getViewAndOffset(this.pos, this.pos + 1);
 		const firstByte = view.getUint8(offset);
 
+		if (firstByte === 0) {
+			return null; // Invalid VINT
+		}
+
 		// Find the position of VINT_MARKER, which determines the width
 		let width = 1;
 		let mask = 1 << 7;
-		while ((firstByte & mask) === 0 && width < MAX_VAR_INT_SIZE) {
+		while ((firstByte & mask) === 0) {
 			width++;
 			mask >>= 1;
 		}
@@ -509,8 +517,11 @@ export class EBMLReader {
 
 	readElementId() {
 		const size = this.readVarIntSize();
-		const id = this.readUnsignedInt(size);
+		if (size === null) {
+			return null;
+		}
 
+		const id = this.readUnsignedInt(size);
 		return id;
 	}
 
@@ -538,6 +549,10 @@ export class EBMLReader {
 
 	readElementHeader() {
 		const id = this.readElementId();
+		if (id === null) {
+			return null;
+		}
+
 		const size = this.readElementSize();
 
 		return { id, size };
@@ -548,13 +563,17 @@ export class EBMLReader {
 		const loadChunkSize = 2 ** 20; // 1 MiB
 		const idsSet = new Set(ids);
 
-		while (this.pos < until - MAX_HEADER_SIZE) {
-			if (!this.reader.rangeIsLoaded(this.pos, this.pos + MAX_HEADER_SIZE)) {
+		while (this.pos <= until - MIN_HEADER_SIZE) {
+			if (!this.reader.rangeIsLoaded(this.pos, Math.min(this.pos + MAX_HEADER_SIZE, until))) {
 				await this.reader.loadRange(this.pos, Math.min(this.pos + loadChunkSize, until));
 			}
 
 			const elementStartPos = this.pos;
 			const elementHeader = this.readElementHeader();
+			if (!elementHeader) {
+				break;
+			}
+
 			if (idsSet.has(elementHeader.id)) {
 				return elementStartPos;
 			}

src/matroska/matroska-demuxer.ts

@@ -239,6 +239,10 @@ export class MatroskaDemuxer extends Demuxer {
 				);
 
 				const header = this.metadataReader.readElementHeader();
+				if (!header) {
+					break; // Zero padding at the end of the file triggers this, for example
+				}
+
 				const id = header.id;
 				let size = header.size;
 				const startPos = this.metadataReader.pos;
@@ -318,14 +322,19 @@ export class MatroskaDemuxer extends Demuxer {
 		);
 
 		let clusterEncountered = false;
-		while (this.metadataReader.pos < this.currentSegment.elementEndPos) {
+		while (this.metadataReader.pos <= this.currentSegment.elementEndPos - MIN_HEADER_SIZE) {
 			await this.metadataReader.reader.loadRange(
 				this.metadataReader.pos,
 				this.metadataReader.pos + MAX_HEADER_SIZE,
 			);
 
 			const elementStartPos = this.metadataReader.pos;
-			const { id, size } = this.metadataReader.readElementHeader();
+			const header = this.metadataReader.readElementHeader();
+			if (!header) {
+				break;
+			}
+
+			const { id, size } = header;
 			const dataStartPos = this.metadataReader.pos;
 
 			const metadataElementIndex = METADATA_ELEMENTS.findIndex(x => x.id === id);
@@ -392,7 +401,10 @@ export class MatroskaDemuxer extends Demuxer {
 				this.metadataReader.pos,
 				this.metadataReader.pos + 2 ** 12, // Load a larger range, assuming the correct element will be there
 			);
-			const { id, size } = this.metadataReader.readElementHeader();
+			const header = this.metadataReader.readElementHeader();
+			if (!header) continue;
+
+			const { id, size } = header;
 			if (id !== target.id) continue;
 
 			assertDefinedSize(size);
@@ -469,6 +481,8 @@ export class MatroskaDemuxer extends Demuxer {
 
 		const elementStartPos = this.metadataReader.pos;
 		const elementHeader = this.metadataReader.readElementHeader();
+		assert(elementHeader);
+
 		const id = elementHeader.id;
 		let size = elementHeader.size;
 		const dataStartPos = this.metadataReader.pos;
@@ -720,12 +734,20 @@ export class MatroskaDemuxer extends Demuxer {
 		const startIndex = reader.pos;
 
 		while (reader.pos - startIndex <= totalSize - MIN_HEADER_SIZE) {
-			this.traverseElement(reader);
+			const foundElement = this.traverseElement(reader);
+			if (!foundElement) {
+				break;
+			}
 		}
 	}
 
-	traverseElement(reader: EBMLReader) {
-		const { id, size } = reader.readElementHeader();
+	traverseElement(reader: EBMLReader): boolean {
+		const header = reader.readElementHeader();
+		if (!header) {
+			return false;
+		}
+
+		const { id, size } = header;
 		const dataStartPos = reader.pos;
 		assertDefinedSize(size);
 
@@ -1113,6 +1135,8 @@ export class MatroskaDemuxer extends Demuxer {
 				if (!this.currentCluster) break;
 
 				const trackNumber = reader.readVarInt();
+				if (trackNumber === null) break;
+
 				const relativeTimestamp = reader.readS16();
 
 				const flags = reader.readU8();
@@ -1148,6 +1172,8 @@ export class MatroskaDemuxer extends Demuxer {
 				if (!this.currentCluster) break;
 
 				const trackNumber = reader.readVarInt();
+				if (trackNumber === null) break;
+
 				const relativeTimestamp = reader.readS16();
 
 				const flags = reader.readU8();
@@ -1184,6 +1210,7 @@ export class MatroskaDemuxer extends Demuxer {
 		}
 
 		reader.pos = dataStartPos + size;
+		return true;
 	}
 }
 
@@ -1562,7 +1589,7 @@ abstract class MatroskaTrackBacking implements InputTrackBacking {
 				}
 			}
 
-			while (metadataReader.pos < segment.elementEndPos) {
+			while (metadataReader.pos <= segment.elementEndPos - MIN_HEADER_SIZE) {
 				if (prevCluster) {
 					const trackData = prevCluster.trackData.get(this.internalTrack.id);
 					if (trackData && trackData.startTimestamp > latestTimestamp) {
@@ -1582,6 +1609,10 @@ abstract class MatroskaTrackBacking implements InputTrackBacking {
 				await metadataReader.reader.loadRange(metadataReader.pos, metadataReader.pos + MAX_HEADER_SIZE);
 				const elementStartPos = metadataReader.pos;
 				const elementHeader = metadataReader.readElementHeader();
+				if (!elementHeader) {
+					break;
+				}
+
 				const id = elementHeader.id;
 				let size = elementHeader.size;
 				const dataStartPos = metadataReader.pos;

src/media-source.ts

@@ -323,17 +323,17 @@ class VideoEncoderWrapper {
 
 			if (this.customEncoder) {
 				this.customEncoderQueueSize++;
-				const promise = this.customEncoderCallSerializer
-					.call(() => this.customEncoder!.encode(videoSample, finalEncodeOptions))
-					.then(() => {
-						this.customEncoderQueueSize--;
 
-						if (shouldClose) {
-							videoSample.close();
-						}
-					})
-					.catch((error: Error) => {
-						this.encoderError ??= error;
+				// We clone the sample so it cannot be closed on us from the outside before it reaches the encoder
+				const clonedSample = videoSample.clone();
+
+				const promise = this.customEncoderCallSerializer
+					.call(() => this.customEncoder!.encode(clonedSample, finalEncodeOptions))
+					.then(() => this.customEncoderQueueSize--)
+					.catch((error: Error) => this.encoderError ??= error)
+					.finally(() => {
+						clonedSample.close();
+						// `videoSample` gets closed in the finally block at the end of the method
 					});
 
 				if (this.customEncoderQueueSize >= 4) {
@@ -440,6 +440,7 @@ class VideoEncoderWrapper {
 						void this.muxer!.addEncodedVideoPacket(this.source._connectedTrack!, packet, meta);
 					},
 					error: (error) => {
+						error.stack = new Error().stack; // Provide a more useful stack trace
 						this.encoderError ??= error;
 					},
 				});
@@ -483,7 +484,6 @@ class VideoEncoderWrapper {
 
 	checkForEncoderError() {
 		if (this.encoderError) {
-			this.encoderError.stack = new Error().stack; // Provide a more useful stack trace
 			throw this.encoderError;
 		}
 	}
@@ -939,17 +939,17 @@ class AudioEncoderWrapper {
 
 			if (this.customEncoder) {
 				this.customEncoderQueueSize++;
-				const promise = this.customEncoderCallSerializer
-					.call(() => this.customEncoder!.encode(audioSample))
-					.then(() => {
-						this.customEncoderQueueSize--;
 
-						if (shouldClose) {
-							audioSample.close();
-						}
-					})
-					.catch((error: Error) => {
-						this.encoderError ??= error;
+				// We clone the sample so it cannot be closed on us from the outside before it reaches the encoder
+				const clonedSample = audioSample.clone();
+
+				const promise = this.customEncoderCallSerializer
+					.call(() => this.customEncoder!.encode(clonedSample))
+					.then(() => this.customEncoderQueueSize--)
+					.catch((error: Error) => this.encoderError ??= error)
+					.finally(() => {
+						clonedSample.close();
+						// `audioSample` gets closed in the finally block at the end of the method
 					});
 
 				if (this.customEncoderQueueSize >= 4) {
@@ -1128,6 +1128,7 @@ class AudioEncoderWrapper {
 						void this.muxer!.addEncodedAudioPacket(this.source._connectedTrack!, packet, meta);
 					},
 					error: (error) => {
+						error.stack = new Error().stack; // Provide a more useful stack trace
 						this.encoderError ??= error;
 					},
 				});
@@ -1266,7 +1267,6 @@ class AudioEncoderWrapper {
 
 	checkForEncoderError() {
 		if (this.encoderError) {
-			this.encoderError.stack = new Error().stack; // Provide a more useful stack trace
 			throw this.encoderError;
 		}
 	}
@@ -1334,16 +1334,17 @@ export class AudioBufferSource extends AudioSource {
 	 * @returns A Promise that resolves once the output is ready to receive more samples. You should await this Promise
 	 * to respect writer and encoder backpressure.
 	 */
-	add(audioBuffer: AudioBuffer) {
+	async add(audioBuffer: AudioBuffer) {
 		if (!(audioBuffer instanceof AudioBuffer)) {
 			throw new TypeError('audioBuffer must be an AudioBuffer.');
 		}
 
-		const audioSamples = AudioSample.fromAudioBuffer(audioBuffer, this._accumulatedTime);
-		const promises = audioSamples.map(sample => this._encoder.add(sample, true));
-
+		const iterator = AudioSample._fromAudioBuffer(audioBuffer, this._accumulatedTime);
 		this._accumulatedTime += audioBuffer.duration;
-		return Promise.all(promises);
+
+		for (const audioSample of iterator) {
+			await this._encoder.add(audioSample, true);
+		}
 	}
 
 	/** @internal */
@@ -1466,10 +1467,10 @@ export class MediaStreamAudioTrackSource extends AudioSource {
 			let totalDuration = 0;
 
 			this._scriptProcessorNode.onaudioprocess = (event) => {
-				const audioSamples = AudioSample.fromAudioBuffer(event.inputBuffer, totalDuration);
+				const iterator = AudioSample._fromAudioBuffer(event.inputBuffer, totalDuration);
 				totalDuration += event.inputBuffer.duration;
 
-				for (const audioSample of audioSamples) {
+				for (const audioSample of iterator) {
 					if (!audioReceived) {
 						audioReceived = true;
 

src/sample.ts

@@ -1067,6 +1067,49 @@ export class AudioSample {
 		(this.timestamp as number) = newTimestamp;
 	}
 
+	/** @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.
@@ -1076,7 +1119,7 @@ export class AudioSample {
 			throw new TypeError('audioBuffer must be an AudioBuffer.');
 		}
 
-		const MAX_FLOAT_COUNT = 64 * 1024 * 1024;
+		const MAX_FLOAT_COUNT = 48000 * 5; // 5 seconds of mono 48 kHz audio per sample
 
 		const numberOfChannels = audioBuffer.numberOfChannels;
 		const sampleRate = audioBuffer.sampleRate;
@@ -1088,14 +1131,14 @@ export class AudioSample {
 
 		const result: AudioSample[] = [];
 
-		// Create AudioData in a chunked fashion so we don't create huge Float32Arrays
+		// 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 * framesToCopy + framesToCopy),
+					chunkData.subarray(channel * framesToCopy, (channel + 1) * framesToCopy),
 					channel,
 					currentRelativeFrame,
 				);

src/source.ts

@@ -314,7 +314,11 @@ export class UrlSource extends Source {
 		} else if (rangeResponse.status === 200) {
 			// The server just returned the whole thing
 			this._fullData = await rangeResponse.arrayBuffer();
-			return this._fullData.byteLength;
+			if (this._fullData.byteLength !== 1) {
+				return this._fullData.byteLength;
+			} else {
+				// The server responded with 200, but returned only the requested range, so skip the response
+			}
 		}
 
 		// If the range request didn't provide the size, make a full GET request