红胖子(红模仿)的博文大全：开发技术集合（包含Qt实用技术、树莓派、三维、OpenCV、OpenGL、ffmpeg、OSG、单片机、软硬结合等等）
需求使用OpenCV库的视频播放器(支持播放器操作，如暂停、恢复、停止、时间、进度条拽托等)。
原理
使用OpenCV打开视频文件，获取总帧数，根据当前帧数，刷新当前时间戳与预期的时间间隔，调用槽函数动态刷新播放内容。
注意
当前只测试了avi文件。
相关博客
《OpenCV开发笔记（四）：OpenCV图片和视频数据的读取与存储》
《项目实战：Qt+OpenCV操作摄像头拍照、调节参数和视频录制》
《项目实战：Qt+OpenCV视频播放器(支持播放器操作，如暂停、恢复、停止、时间、进度条拽托等)》
《Qt实用技巧：使用QMediaPlayer和Windows自带组件播放swf、rmvb、mpg、mp4等视频文件》
《Qt实用技巧：使用QMediaPlayer播放mp4文件》
Demo：OpenCVPlayer v1.0.0
运行效果
下载地址
CSDN：javascript:void(0)
核心类代码
OpenCVPlayerManager.h
#ifndef OPENCVPLAYERMANAGER_H
#define OPENCVPLAYERMANAGER_H
/************************************************************\
* 控件名称： OpenCVPlayerManager，OpenCV管理类
* 控件描述：
* 1.OpenCV打开视频文件
* 2.播放器操作：播放、暂停、停止
* 3.播放时显示：当前时间、总时间
* 4.设置当前播放的时间点
*
* 作者：红模仿 联系方式：QQ21497936
* 博客地址：javascript:void(0)
* 日期 版本 描述
* 2019年11月25日 v1.0.0 opencv打开文件
\************************************************************/
#include <QObject>
#include <QImage>
#include <QTimer>
#include <QElapsedTimer>
// opencv
#include "opencv/highgui.h"
#include "opencv/cxcore.h"
#include "opencv2/core/core.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/opencv.hpp"
class OpenCVPlayerManager : public QObject
{
Q_OBJECT
public:
enum PLAY_STATE {
PLAY_STATE_PLAYING,
PLAY_STATE_PAUSE,
PLAY_STATE_STOP
};
public:
explicit OpenCVPlayerManager(QObject *parent = 0);
~OpenCVPlayerManager();
public:
QString getWindowTitle() const;
public:
void setWindowTitle(const QString &windowTitle);
signals:
void signal_captureOneFrame(cv::Mat mat); // 接收图像后抛出信号
void signal_playStateChanged(OpenCVPlayerManager::PLAY_STATE playState);
// 播放器状态
void signal_durationChanged(qint64 duration); // 视频总长度
void signal_positionChanged(qint64 position); // 当前位置
public:
bool startPlay(QString filePath, int width = 480, int height = 320);
void pause(); // 暂停
void resume(); // 恢复播放
void stopPlay(); // 停止播放
void setPosition(qint64 position); // 切换到播放位置
public slots:
bool slot_start(); // 开启线程
bool stop(); // 关闭线程
protected slots:
void slot_captrueFrame(); // 消息循环获取图像
void slot_stopPlay(); // 停止播放
void slot_setPosition(qint64 position);
public:
static QImage cvMat2QImage(const cv::Mat &mat);
private:
cv::VideoCapture *_pVideoCapture; // 播放文件实例
QString _filePath; // 播放文件路径
bool _running; // 线程是否运行
int _totalFrames; // 总帧数
int _fps; // 每秒帧数
int _currentFrame; // 当前帧数
int _width; // 高度
int _height; // 宽度
QElapsedTimer _elapsedTimer; // 计时器
qint64 _pauseMs; // 暂停的毫秒
qint64 _duration; // 视频总长度(毫秒)
PLAY_STATE _playState; // 播放器状态
int _position; // 改变到的播放位置
bool _setPostion; // 播放位置修改标志
private:
QString _windowTitle;
};
#endif // OPENCVPLAYERMANAGER_H
OpenCVPlayerManager.cpp
#include "OpenCVPlayerManager.h"
#include <QDebug>
OpenCVPlayerManager::OpenCVPlayerManager(QObject *parent)
: QObject(parent),
_pVideoCapture(0),
_totalFrames(0),
_currentFrame(0),
_playState(PLAY_STATE_STOP),
_pauseMs(0),
_duration(0)
{
QString version = "v1.0.0";
_windowTitle = QString("OpenCVPlayer %1(红模仿-红胖子 QQ21497936 博客地址: blog.csdn.net/qq21497936").arg(version);
}
OpenCVPlayerManager::~OpenCVPlayerManager()
{
}
bool OpenCVPlayerManager::startPlay(QString filePath, int width, int height)
{
// 状态判断
switch (_playState)
{
case PLAY_STATE_PAUSE:
resume();
case PLAY_STATE_PLAYING:
return true;
break;
case PLAY_STATE_STOP:
break;
default:
break;
}
if(!_pVideoCapture->open(filePath.toStdString()))
{
qDebug() << __FILE__ << __LINE__ << "Failed to start video :" << filePath;
return false;
}
_width = width;
_height = height;
_pVideoCapture->set(CV_CAP_PROP_FRAME_WIDTH, _width);
_pVideoCapture->set(CV_CAP_PROP_FRAME_HEIGHT, _height);
_width = _pVideoCapture->get(CV_CAP_PROP_FRAME_WIDTH);
_height = _pVideoCapture->get(CV_CAP_PROP_FRAME_HEIGHT);
_fps = _pVideoCapture->get(CV_CAP_PROP_FPS);
_totalFrames = _pVideoCapture->get(CV_CAP_PROP_FRAME_COUNT);
qDebug() << __FILE__ << __LINE__ << "width =" << width;
qDebug() << __FILE__ << __LINE__ << "height =" << height;
qDebug() << __FILE__ << __LINE__ << "_width =" << _width;
qDebug() << __FILE__ << __LINE__ << "_height =" << _height;
qDebug() << __FILE__ << __LINE__ << "_fps =" << _fps;
qDebug() << __FILE__ << __LINE__ << "_totalFrames =" << _totalFrames;
_currentFrame = 0;
_pauseMs = 0;
QTimer::singleShot(0, this, SLOT(slot_captrueFrame()));
_elapsedTimer.start();
_playState = PLAY_STATE_PLAYING;
emit signal_playStateChanged(_playState);
_duration = (_totalFrames - 1) * (1000.0f / _fps);
emit signal_durationChanged(_duration);
return true;
}
void OpenCVPlayerManager::pause()
{
// 状态判断
switch (_playState)
{
case PLAY_STATE_PAUSE:
case PLAY_STATE_STOP:
return;
break;
case PLAY_STATE_PLAYING:
break;
default:
break;
}
_playState = PLAY_STATE_PAUSE;
emit signal_playStateChanged(_playState);
}
void OpenCVPlayerManager::resume()
{
// 状态判断
switch (_playState)
{
case PLAY_STATE_PLAYING:
case PLAY_STATE_STOP:
return;
break;
case PLAY_STATE_PAUSE:
break;
default:
break;
}
QTimer::singleShot(0, this, SLOT(slot_captrueFrame()));
_elapsedTimer.start();
_playState = PLAY_STATE_PLAYING;
emit signal_playStateChanged(_playState);
}
void OpenCVPlayerManager::stopPlay()
{
// 状态判断
switch (_playState)
{
case PLAY_STATE_STOP:
return;
break;
case PLAY_STATE_PAUSE:
case PLAY_STATE_PLAYING:
break;
default:
break;
}
QTimer::singleShot(0, this, SLOT(slot_stopPlay()));
}
void OpenCVPlayerManager::setPosition(qint64 position)
{
QMetaObject::invokeMethod(this, "slot_setPosition", Q_ARG(qint64, position));
}
void OpenCVPlayerManager::slot_setPosition(qint64 position)
{
// 当前帧数
_currentFrame = position / (1000.0f / _fps);
_pauseMs = _currentFrame * (1000.0f / _fps);
_pVideoCapture->set(CV_CAP_PROP_POS_FRAMES, _currentFrame);
_elapsedTimer.start();
qDebug() << __FILE__ << __LINE__
<< _currentFrame << ":" << _totalFrames << ":" << _pauseMs;
}
bool OpenCVPlayerManager::slot_start()
{
_pVideoCapture = new cv::VideoCapture;
_running = true;
}
bool OpenCVPlayerManager::stop()
{
if(_running)
{
_running = false;
delete _pVideoCapture;
_pVideoCapture = 0;
}
}
void OpenCVPlayerManager::slot_captrueFrame()
{
if(!_running)
{
return;
}
if(_pVideoCapture->isOpened())
{
// 没有下一帧，表示播放结束
if(_currentFrame >= _totalFrames)
{
_playState = PLAY_STATE_STOP;
emit signal_playStateChanged(_playState);
cv::Mat mat(_height, _width, CV_8UC3, cv::Scalar(0, 0, 0));
emit signal_captureOneFrame(mat);
return;
}
cv::Mat mat;
*_pVideoCapture >> mat;
emit signal_captureOneFrame(mat);
if(_currentFrame % _fps == 0)
{
emit signal_positionChanged(_currentFrame * (1000.0f / _fps));
}
_currentFrame++;
int nowTime;
switch (_playState)
{
case PLAY_STATE_STOP:
case PLAY_STATE_PAUSE:
_pauseMs = _currentFrame * (1000.0 / _fps);
break;
case PLAY_STATE_PLAYING:
nowTime = _elapsedTimer.elapsed();
if((_currentFrame * (1000.0 / _fps) - (nowTime + _pauseMs) < 0))
{
QTimer::singleShot(0, this, SLOT(slot_captrueFrame()));
}else{
QTimer::singleShot(_currentFrame * (1000.0 / _fps)
- (nowTime + _pauseMs), this, SLOT(slot_captrueFrame()));
}
break;
default:
break;
}
}
}
void OpenCVPlayerManager::slot_stopPlay()
{
if(_pVideoCapture->isOpened())
{
_playState = PLAY_STATE_STOP;
_pVideoCapture->release();
cv::Mat mat(_width, _height, CV_8UC3, cv::Scalar(0, 0, 0));
emit signal_captureOneFrame(mat);
_currentFrame = 0;
emit signal_positionChanged(0);
_duration = 0;
emit signal_durationChanged(_duration);
}
}
QImage OpenCVPlayerManager::cvMat2QImage(const cv::Mat &mat)
{
// 8-bits unsigned, NO. OF CHANNELS = 1
if(mat.type() == CV_8UC1)
{
QImage image(mat.cols, mat.rows, QImage::Format_Indexed8);
// Set the color table (used to translate colour indexes to qRgb values)
image.setColorCount(256);
for(int i = 0; i < 256; i++)
{
image.setColor(i, qRgb(i, i, i));
}
// Copy input Mat
uchar *pSrc = mat.data;
for(int row = 0; row < mat.rows; row ++)
{
uchar *pDest = image.scanLine(row);
memcpy(pDest, pSrc, mat.cols);
pSrc += mat.step;
}
return image;
}
// 8-bits unsigned, NO. OF CHANNELS = 3
else if(mat.type() == CV_8UC3)
{
// Copy input Mat
const uchar *pSrc = (const uchar*)mat.data;
// Create QImage with same dimensions as input Mat
QImage image(pSrc, mat.cols, mat.rows, mat.step, QImage::Format_RGB888);
QImage image2 = image.rgbSwapped();
return image2;
}
else if(mat.type() == CV_8UC4)
{
qDebug() << "CV_8UC4";
// Copy input Mat
const uchar *pSrc = (const uchar*)mat.data;
// Create QImage with same dimensions as input Mat
QImage image(pSrc, mat.cols, mat.rows, mat.step, QImage::Format_ARGB32);
// return image.copy();
return image;
}
else
{
qDebug() << "ERROR: Mat could not be converted to QImage.";
QImage image;
return image;
}
}
QString OpenCVPlayerManager::getWindowTitle() const
{
return _windowTitle;
}
void OpenCVPlayerManager::setWindowTitle(const QString &windowTitle)
{
_windowTitle = windowTitle;
}
入坑
入坑一：调整播放位置时，宕机
原因：
直接主线程操作设置当前帧的位置，同时子线程也却在读取，OpenCV内部没有错异步处理。
解决方法：
先调用设置位置，然后槽调用，将设置位置放置到子线程当中去。
