libopenshot/src/Qt/AudioPlaybackThread.cpp

/**
 * @file
 * @brief Source file for AudioPlaybackThread class
 * @author Duzy Chan <code@duzy.info>
 * @author Jonathan Thomas <jonathan@openshot.org> *
 *
 * @section LICENSE
 *
 * Copyright (c) 2008-2014 OpenShot Studios, LLC
 * <http://www.openshotstudios.com/>. This file is part of
 * OpenShot Library (libopenshot), an open-source project dedicated to
 * delivering high quality video editing and animation solutions to the
 * world. For more information visit <http://www.openshot.org/>.
 *
 * OpenShot Library (libopenshot) is free software: you can redistribute it
 * and/or modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * OpenShot Library (libopenshot) is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
 */

#include "../../include/Qt/AudioPlaybackThread.h"

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(int numChannels)
	{
		if (!m_pInstance) {
			// Create the actual instance of device manager only once
			m_pInstance = new AudioDeviceManagerSingleton;

			// Initialize audio device only 1 time
            m_pInstance->audioDeviceManager.initialise (
					0, /* number of input channels */
                    numChannels, /* number of output channels */
					0, /* no XML settings.. */
					true  /* select default device on failure */);
		}

		return m_pInstance;
	}

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

    // Constructor
    AudioPlaybackThread::AudioPlaybackThread()
	: 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(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<Frame> AudioPlaybackThread::getFrame()
    {
	if (source) return source->getFrame();
	return std::shared_ptr<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(numChannels)->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)
					usleep(2500);

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

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

				player.setSource(NULL);
				AudioDeviceManagerSingleton::Instance(0)->audioDeviceManager.removeAudioCallback(&player);

				// Remove source
				delete source;
				source = NULL;

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

    }
}