点击上方“小白学视觉”，选择加"星标"或“置顶”
重磅干货，第一时间送达需求
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
运行效果
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：https://blog.csdn.net/qq21497936* 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_HOpenCVPlayerManager.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 = 1if(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 Matuchar *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 = 3else if(mat.type() == CV_8UC3){// Copy input Matconst uchar *pSrc = (const uchar*)mat.data;// Create QImage with same dimensions as input MatQImage 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 Matconst uchar *pSrc = (const uchar*)mat.data;// Create QImage with same dimensions as input MatQImage 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;
}槽点
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。
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