Class AudioEncoderPolyfill

src/audio_encoder.ts:61–695

 * Corresponds to the WebCodecs AudioEncoder API.
 */
export class AudioEncoderPolyfill extends EventTarget {
	private init: AudioEncoderInit;
	private config: AudioEncoderConfig | null = null;
	private codecContext: CodecContext | null = null;
	private mutex = new AsyncMutex();
	private frame: Frame;
	private packet: Packet;
	private _encodeQueueSize = 0;
	private currentConfigId = 0;
	private chunkOutputted = false;
	private chunkTimestampOffset = 0;
	private pendingFlushResolvers: Array<{ resolve: () => void; reject: (e: unknown) => void }> = [];
	private resampler: SoftwareResampleContext | null = null;
	private lastResamplerKey: string | null = null;
	private dstFrame: Frame | null = null;
	private nextPts: bigint = 0n;
	private aacAudioSpecificConfig: AacAudioSpecificConfig | null = null;
	private resampledSampleCount: number = 0;

	private _state: AudioEncoder['state'] = 'unconfigured';
	/**
	 * The current state of the encoder: "unconfigured", "configured", or "closed".
	 */
	get state() {
		return this._state;
	}

	/**
	 * The number of pending encode operations.
	 */
	get encodeQueueSize() {
		return this._encodeQueueSize;
	}

	/**
	 * Event handler called when an encode operation completes and leaves the queue.
	 */
	ondequeue: ((this: AudioEncoder, ev: Event) => unknown) | null = null;

	/**
	 * Creates a new AudioEncoder.
	 */
	constructor(init: AudioEncoderInit) {
		super();

		if (!init.output || !init.error) {
			throw new TypeError('AudioEncoderInit requires \'output\' and \'error\' callbacks.');
		}

		this.init = init;
		this.frame = new Frame();
		this.frame.alloc();
		this.packet = new Packet();
		this.packet.alloc();
	}

	private static createCodecContext(config: AudioEncoderConfig) {
		const inferred = inferCodecFromCodecString(config.codec);