VideoCacheThread.cpp

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/**
 * @file
 * @brief Source file for VideoCacheThread class
 * @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/VideoCacheThread.h"

namespace openshot
{
        // Constructor
        VideoCacheThread::VideoCacheThread()
        : Thread("video-cache"), speed(1), is_playing(false), position(1)
        , reader(NULL), max_frames(OPEN_MP_NUM_PROCESSORS * 2), current_display_frame(1)
    {
    }

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

    // Get the currently playing frame number (if any)
    int VideoCacheThread::getCurrentFramePosition()
    {
        if (frame)
                return frame->number;
        else
                return 0;
    }

    // Set the currently playing frame number (if any)
    void VideoCacheThread::setCurrentFramePosition(int current_frame_number)
    {
        current_display_frame = current_frame_number;
    }

        // Seek the audio thread
        void VideoCacheThread::Seek(int new_position)
        {
                position = new_position;
        }

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

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

    // Start the thread
    void VideoCacheThread::run()
    {
        while (!threadShouldExit() && is_playing) {

                // Calculate sleep time for frame rate
                double frame_time = (1000.0 / reader->info.fps.ToDouble());

            // Cache frames before the other threads need them
            // Cache frames up to the max frames
            while (speed == 1 && (position - current_display_frame) < max_frames)
            {
                // Only cache up till the max_frames amount... then sleep
                        try
                        {
                                if (reader)
                                        // Force the frame to be generated
                                        reader->GetFrame(position);

                        }
                        catch (const OutOfBoundsFrame & e)
                        {
                                // Ignore out of bounds frame exceptions
                        }

                // Increment frame number
                position++;
            }

                // Sleep for 1 frame length
                sleep(frame_time);
        }

        return;
    }
}