Method pullResampledFrames

src/audio_encoder.ts:516–568

(configId: number, draining: boolean = false)

	}

	private async pullResampledFrames(configId: number, draining: boolean = false) {
		assert(this.codecContext);
		assert(this.resampler);
		assert(this.dstFrame);

		const frameSize = this.codecContext.frameSize > 0
			? this.codecContext.frameSize
			: 1024; // Fallback for variable frame size codecs

		// When draining, we gotta pad with silence to reach a multiple of frameSize (except for AAC because it
		// sometimes caused a weird "Input contains (near) NaN/+-Inf" error and I wasn't sure why).
		if (draining && this.codecContext.frameSize > 0 && this.codecContext.codecId !== AV_CODEC_ID_AAC) {
			const remainder = this.resampledSampleCount % frameSize;

			if (remainder > 0) {
				const padSamples = frameSize - remainder;
				const padBuffers = this.createInputSilenceBuffers(padSamples);
				await this.resampler.convert(null, 0, padBuffers, padSamples);
				this.resampledSampleCount += padSamples;
			}
		}

		while (true) {
			const outputBuffers = this.createOutputBuffers(frameSize);
			const got = await this.resampler.convert(outputBuffers, frameSize, null, 0);

			if (draining ? got <= 0 : got < frameSize) {
				break;
			}

			// Set up the destination frame and copy data
			this.dstFrame.unref();
			this.dstFrame.format = this.codecContext.sampleFormat;
			this.dstFrame.channelLayout = this.codecContext.channelLayout;
			this.dstFrame.sampleRate = this.codecContext.sampleRate;
			this.dstFrame.nbSamples = got;
			this.dstFrame.allocBuffer();

			const concatenated = Buffer.concat(outputBuffers);
			this.dstFrame.fromBuffer(concatenated);

			this.dstFrame.pts = this.nextPts;
			const durationMicros = BigInt(Math.floor(1e6 * got / this.codecContext.sampleRate));
			this.dstFrame.duration = durationMicros;
			this.nextPts += durationMicros;

			await this.sendFrameAndReceivePackets(this.dstFrame, configId);

			if (draining && got < frameSize) {
				break;
			}
		}
	}

	/**
	 * Flushes all pending encode operations and waits for completion.