Method encodeInternal

src/audio_encoder.ts:334–431

(clonedData: AudioData)

	}

	private async encodeInternal(clonedData: AudioData) {
		const currentConfigId = this.currentConfigId;

		using lock = this.mutex.lock();
		await lock.ready; // Unconditional await here to queue a microtask

		if (this.currentConfigId !== currentConfigId) {
			clonedData.close();
			return;
		}

		// Spec: Decrement [[encodeQueueSize]] and run the Schedule Dequeue Event algorithm.
		this.decrementQueue();

		try {
			assert(this.codecContext);

			if (clonedData instanceof AudioDataPolyfill && clonedData._data instanceof Frame) {
				const otherFrame = clonedData._data;
				this.frame.ref(otherFrame);
			} else {
				// Copy audio data from AudioData to FFmpeg Frame
				const format = fromAudioSampleFormat(clonedData.format!);
				this.frame.format = format;
				this.frame.nbSamples = clonedData.numberOfFrames;
				this.frame.sampleRate = clonedData.sampleRate;
				this.frame.channelLayout = getChannelLayout(clonedData.numberOfChannels);
				this.frame.pts = BigInt(clonedData.timestamp);
				this.frame.duration = BigInt(clonedData.duration);

				// Allocate buffer and copy data
				this.frame.allocBuffer();

				// Copy data from AudioData to frame buffer
				const size = clonedData.allocationSize({ planeIndex: 0 });
				const buffer = Buffer.alloc(size);
				clonedData.copyTo(buffer, { planeIndex: 0 });
				this.frame.fromBuffer(buffer);
			}
		} finally {
			clonedData.close();
		}

		// 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 SoftwareResampleContext();
			}

			const key = `${this.frame.sampleRate}:${this.frame.channels}:${this.frame.format}`;