libopenshot/src/Qt/AudioPlaybackThread.cpp

/**
 * @file
 * @brief Source file for AudioPlaybackThread class
 * @author Duzy Chan <code@duzy.info>
 * @author Jonathan Thomas <jonathan@openshot.org> *
 *
 * @ref License
 */

// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later

#include "AudioPlaybackThread.h"
#include "Settings.h"

#include "../ReaderBase.h"
#include "../RendererBase.h"
#include "../AudioReaderSource.h"
#include "../AudioDevices.h"
#include "../Settings.h"

#include <thread>    // for std::this_thread::sleep_for
#include <chrono>    // for std::chrono::milliseconds

using namespace juce;

namespace openshot
{

	// Global reference to device manager
	AudioDeviceManagerSingleton *AudioDeviceManagerSingleton::m_pInstance = NULL;

	// Create or Get an instance of the device manager singleton
	AudioDeviceManagerSingleton *AudioDeviceManagerSingleton::Instance()
	{
		if (!m_pInstance) {
			// Create the actual instance of device manager only once
			m_pInstance = new AudioDeviceManagerSingleton;
			auto* mgr = &m_pInstance->audioDeviceManager;

			// Get preferred audio device name and type (if any)
			auto selected_device = juce::String(
				Settings::Instance()->PLAYBACK_AUDIO_DEVICE_NAME);
			auto selected_type = juce::String(
				Settings::Instance()->PLAYBACK_AUDIO_DEVICE_TYPE);

			if (selected_type.isEmpty() && !selected_device.isEmpty()) {
				// Look up type for the selected device
				for (const auto t : mgr->getAvailableDeviceTypes()) {
					for (const auto n : t->getDeviceNames()) {
						if (selected_device.trim().equalsIgnoreCase(n.trim())) {
							selected_type = t->getTypeName();
							break;
						}
					}
					if(!selected_type.isEmpty())
						break;
				}
			}

			if (!selected_type.isEmpty())
				m_pInstance->audioDeviceManager.setCurrentAudioDeviceType(selected_type, true);

			// Initialize audio device only 1 time
			juce::String audio_error = m_pInstance->audioDeviceManager.initialise (
				0,       // number of input channels
				2,       // number of output channels
				nullptr, // no XML settings..
				true,    // select default device on failure
				selected_device // preferredDefaultDeviceName
			);

			// Persist any errors detected
			if (audio_error.isNotEmpty()) {
				m_pInstance->initialise_error = audio_error.toStdString();
			} else {
				m_pInstance->initialise_error = "";
			}
		}

		return m_pInstance;
	}

    // Close audio device
    void AudioDeviceManagerSingleton::CloseAudioDevice()
    {
        // Close Audio Device
        audioDeviceManager.closeAudioDevice();
        audioDeviceManager.removeAllChangeListeners();
        audioDeviceManager.dispatchPendingMessages();
    }

    // Constructor
    AudioPlaybackThread::AudioPlaybackThread()
	: juce::Thread("audio-playback")
	, player()
	, transport()
	, mixer()
	, source(NULL)
	, sampleRate(0.0)
	, numChannels(0)
    , buffer_size(12000)
    , is_playing(false)
	, time_thread("audio-buffer")
    {
	}

    // Destructor
    AudioPlaybackThread::~AudioPlaybackThread()
    {
    }

    // Set the reader object
    void AudioPlaybackThread::Reader(openshot::ReaderBase *reader) {
		if (source)
			source->Reader(reader);
		else {
			// Create new audio source reader
			source = new AudioReaderSource(reader, 1, buffer_size);
			source->setLooping(true); // prevent this source from terminating when it reaches the end
		}

		// Set local vars
		sampleRate = reader->info.sample_rate;
		numChannels = reader->info.channels;

		// TODO: Update transport or audio source's sample rate, incase the sample rate
		// is different than the original Reader

		// Mark as 'playing'
		Play();
	}

    // Get the current frame object (which is filling the buffer)
    std::shared_ptr<openshot::Frame> AudioPlaybackThread::getFrame()
    {
	if (source) return source->getFrame();
	return std::shared_ptr<openshot::Frame>();
    }

    // Get the currently playing frame number
    int64_t AudioPlaybackThread::getCurrentFramePosition()
    {
	return source ? source->getEstimatedFrame() : 0;
    }

	// Seek the audio thread
	void AudioPlaybackThread::Seek(int64_t new_position)
	{
		source->Seek(new_position);
	}

	// Play the audio
	void AudioPlaybackThread::Play() {
		// Start playing
		is_playing = true;
	}

	// Stop the audio
	void AudioPlaybackThread::Stop() {
		// Stop playing
		is_playing = false;
	}

	// Start audio thread
    void AudioPlaybackThread::run()
    {
    	while (!threadShouldExit())
    	{
    		if (source && !transport.isPlaying() && is_playing) {

    			// Start new audio device (or get existing one)
    			// Add callback
				AudioDeviceManagerSingleton::Instance()->audioDeviceManager.addAudioCallback(&player);

    			// Create TimeSliceThread for audio buffering
				time_thread.startThread();

    			// Connect source to transport
    			transport.setSource(
    			    source,
    			    buffer_size, // tells it to buffer this many samples ahead
    			    &time_thread,
    			    sampleRate,
    			    numChannels);
    			transport.setPosition(0);
    			transport.setGain(1.0);

    			// Connect transport to mixer and player
    			mixer.addInputSource(&transport, false);
    			player.setSource(&mixer);

    			// Start the transport
    			transport.start();

    			while (!threadShouldExit() && transport.isPlaying() && is_playing)
					std::this_thread::sleep_for(std::chrono::milliseconds(2));

				// Stop audio and shutdown transport
				Stop();
				transport.stop();

				// Kill previous audio
				transport.setSource(NULL);

				player.setSource(NULL);
				AudioDeviceManagerSingleton::Instance()->audioDeviceManager.removeAudioCallback(&player);

				// Remove source
				delete source;
				source = NULL;

				// Stop time slice thread
				time_thread.stopThread(-1);
    		}
    	}

    }
}