Big realtime playback refactor

- Added Worker- or AudioContext-based fallbacks in case MediaStreamTrackProcessor is not available
- Fixed fMP4-streamed files not playing in Safari
- Added better error handling for MediaStream sources
- Improved the live recording example to be more robust

src/sample.ts

@@ -1063,6 +1063,58 @@ export class AudioSample {
 		// eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
 		(this.timestamp as number) = newTimestamp;
 	}
+
+	/**
+	 * Creates AudioSamples from an AudioBuffer, starting at the given timestamp. 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 = 64 * 1024 * 1024;
+
+		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 AudioData 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),
+					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 => {