PlayerPrivate.cpp
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/**
* @file
* @brief Source file for PlayerPrivate class
* @author Duzy Chan <code@duzy.info>
* @author Jonathan Thomas <jonathan@openshot.org>
*
* @ref License
*/
/* LICENSE
*
* Copyright (c) 2008-2019 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/PlayerPrivate.h"
namespace openshot
{
// Constructor
PlayerPrivate::PlayerPrivate(openshot::RendererBase *rb)
: renderer(rb), Thread("player"), video_position(1), audio_position(0)
, audioPlayback(new openshot::AudioPlaybackThread())
, videoPlayback(new openshot::VideoPlaybackThread(rb))
, videoCache(new openshot::VideoCacheThread())
, speed(1), reader(NULL), last_video_position(1)
{ }
// Destructor
PlayerPrivate::~PlayerPrivate()
{
stopPlayback(1000);
delete audioPlayback;
delete videoCache;
delete videoPlayback;
}
// Start thread
void PlayerPrivate::run()
{
// bail if no reader set
if (!reader)
return;
// Start the threads
if (reader->info.has_audio)
audioPlayback->startThread(8);
if (reader->info.has_video) {
videoCache->startThread(2);
videoPlayback->startThread(4);
}
while (!threadShouldExit()) {
// Calculate the milliseconds a single frame should stay on the screen
double frame_time = (1000.0 / reader->info.fps.ToDouble());
// Get the start time (to track how long a frame takes to render)
const Time t1 = Time::getCurrentTime();
// Get the current video frame (if it's different)
frame = getFrame();
// Experimental Pausing Code (if frame has not changed)
if ((speed == 0 && video_position == last_video_position) || (video_position > reader->info.video_length)) {
speed = 0;
sleep(frame_time);
continue;
}
// Set the video frame on the video thread and render frame
videoPlayback->frame = frame;
videoPlayback->render.signal();
// Keep track of the last displayed frame
last_video_position = video_position;
// How many frames ahead or behind is the video thread?
int64_t video_frame_diff = 0;
if (reader->info.has_audio && reader->info.has_video) {
if (speed != 1)
// Set audio frame again (since we are not in normal speed, and not paused)
audioPlayback->Seek(video_position);
// Only calculate this if a reader contains both an audio and video thread
audio_position = audioPlayback->getCurrentFramePosition();
video_frame_diff = video_position - audio_position;
}
// Get the end time (to track how long a frame takes to render)
const Time t2 = Time::getCurrentTime();
// Determine how many milliseconds it took to render the frame
int64_t render_time = t2.toMilliseconds() - t1.toMilliseconds();
// Calculate the amount of time to sleep (by subtracting the render time)
int sleep_time = int(frame_time - render_time);
// Debug
ZmqLogger::Instance()->AppendDebugMethod("PlayerPrivate::run (determine sleep)", "video_frame_diff", video_frame_diff, "video_position", video_position, "audio_position", audio_position, "speed", speed, "render_time", render_time, "sleep_time", sleep_time);
// Adjust drift (if more than a few frames off between audio and video)
if (video_frame_diff > 0 && reader->info.has_audio && reader->info.has_video)
// Since the audio and video threads are running independently, they will quickly get out of sync.
// To fix this, we calculate how far ahead or behind the video frame is, and adjust the amount of time
// the frame is displayed on the screen (i.e. the sleep time). If a frame is ahead of the audio,
// we sleep for longer. If a frame is behind the audio, we sleep less (or not at all), in order for
// the video to catch up.
sleep_time += (video_frame_diff * (1000.0 / reader->info.fps.ToDouble()));
else if (video_frame_diff < -10 && reader->info.has_audio && reader->info.has_video) {
// Skip frame(s) to catch up to the audio (if more than 10 frames behind)
video_position += abs(video_frame_diff) / 2; // Seek forward 1/2 the difference
sleep_time = 0; // Don't sleep now... immediately go to next position
}
// Sleep (leaving the video frame on the screen for the correct amount of time)
if (sleep_time > 0) usleep(sleep_time * 1000);
}
}
// Get the next displayed frame (based on speed and direction)
std::shared_ptr<openshot::Frame> PlayerPrivate::getFrame()
{
try {
// Get the next frame (based on speed)
if (video_position + speed >= 1 && video_position + speed <= reader->info.video_length)
video_position = video_position + speed;
if (frame && frame->number == video_position && video_position == last_video_position) {
// return cached frame
return frame;
}
else
{
// Update cache on which frame was retrieved
videoCache->setCurrentFramePosition(video_position);
// return frame from reader
return reader->GetFrame(video_position);
}
} catch (const ReaderClosed & e) {
// ...
} catch (const TooManySeeks & e) {
// ...
} catch (const OutOfBoundsFrame & e) {
// ...
}
return std::shared_ptr<openshot::Frame>();
}
// Start video/audio playback
bool PlayerPrivate::startPlayback()
{
if (video_position < 0) return false;
stopPlayback(-1);
startThread(1);
return true;
}
// Stop video/audio playback
void PlayerPrivate::stopPlayback(int timeOutMilliseconds)
{
if (isThreadRunning()) stopThread(timeOutMilliseconds);
if (audioPlayback->isThreadRunning() && reader->info.has_audio) audioPlayback->stopThread(timeOutMilliseconds);
if (videoCache->isThreadRunning() && reader->info.has_video) videoCache->stopThread(timeOutMilliseconds);
if (videoPlayback->isThreadRunning() && reader->info.has_video) videoPlayback->stopThread(timeOutMilliseconds);
}
}
openshot::RendererBase
This is the base class of all Renderers in libopenshot.
Definition: RendererBase.h:49
openshot
This namespace is the default namespace for all code in the openshot library.
Definition: AudioBufferSource.h:39