Method openStream

src/rtaudio.cpp:138–202

	}

	void openStream() {
		// Open new device
		if (deviceInfo.outputChannels == 0 && deviceInfo.inputChannels == 0) {
			throw Exception("RtAudio %s device %d has 0 inputs and 0 outputs", driver->getName().c_str(), deviceId);
		}

		inputParameters = RtAudio::StreamParameters();
		inputParameters.deviceId = deviceId;
		inputParameters.nChannels = deviceInfo.inputChannels;
		inputParameters.firstChannel = 0;

		outputParameters = RtAudio::StreamParameters();
		outputParameters.deviceId = deviceId;
		outputParameters.nChannels = deviceInfo.outputChannels;
		outputParameters.firstChannel = 0;

		options = RtAudio::StreamOptions();
		// options.flags |= RTAUDIO_MINIMIZE_LATENCY;
		options.flags |= RTAUDIO_SCHEDULE_REALTIME;
		options.numberOfBuffers = 2;
		options.streamName = "VCV Rack";

		int32_t closestSampleRate = deviceInfo.preferredSampleRate;
		if (sampleRate > 0) {
			// Find the closest sample rate to the requested one.
			for (int32_t sr : deviceInfo.sampleRates) {
				if (std::fabs(sr - sampleRate) < std::fabs(closestSampleRate - sampleRate)) {
					closestSampleRate = sr;
				}
			}
		}

		if (blockSize <= 0) {
			// DirectSound should use a higher default block size
			if (driver->api == RtAudio::WINDOWS_DS)
				blockSize = 1024;
			else
				blockSize = 256;
		}

		INFO("Opening RtAudio %s device %d: %s (%d in, %d out, %d sample rate, %d block size)", driver->getName().c_str(), deviceId, deviceInfo.name.c_str(), inputParameters.nChannels, outputParameters.nChannels, closestSampleRate, blockSize);
		if (rtAudio->openStream(
			outputParameters.nChannels > 0 ? &outputParameters : NULL,
			inputParameters.nChannels > 0 ? &inputParameters : NULL,
			RTAUDIO_FLOAT32, closestSampleRate, (unsigned int*) &blockSize,
			&rtAudioCallback, this, &options)) {
			throw Exception("Failed to open RtAudio %s device %d", driver->getName().c_str(), deviceId);
		}

		try {
			INFO("Starting RtAudio %s device %d", driver->getName().c_str(), deviceId);
			if (rtAudio->startStream()) {
				throw Exception("Failed to start RtAudio %s device %d", driver->getName().c_str(), deviceId);
			}

			// Update sample rate to actual value
			sampleRate = rtAudio->getStreamSampleRate();