马上工作需要做视频软件了,所以准备学习QT来开发,为什么选择QT呢,因为他优点多多(不说了自己网上g一下 )
随着高清的不断普及,所有视频软件都向高清这个方向而前进,其中有一款开源跨平台的播放器vlc的特性和功能都是非
常的好,所以想准备学习vlc的源码来看看,在看他源码的时候,发现他还有一个可供开发人员调用的libvlc 媒体库可用(GPL),而vlc本身使用的GUI就是QT。
好了不多说了
先装好QT SDK,然后把环境变量设置一下(不会去G!)
然后把vlc库加入到mingw里面
先复制vlc-include.rar解压出来的头文件到Qt\2009.04\mingw\include里面
在把vlc-lib.rar解压出来的文件放到C:\vlc-lib
我们在 Qt Creator 里面建立一个空的QT项目
新建一个Player类 ,会多出player.cpp,player.h 修改成如下
player.cpp
/* * Flie Name player.cpp */ #include "player.h" #include <QVBoxLayout> #include <QPushButton> #include <QSlider> #include <QTimer> #include <QFrame> Player::Player() : QWidget() { //preparation of the vlc command const char * const vlc_args[] = { "-I", "dummy", /* Don't use any interface */ "--ignore-config", /* Don't use VLC's config */ "--extraintf=logger", //log anything "--verbose=2", //be much more verbose then normal for debugging purpose "--plugin-path=C:\\vlc-0.9.9-win32\\plugins\\" }; _videoWidget=new QFrame(this); _volumeSlider=new QSlider(Qt::Horizontal,this); _volumeSlider->setMaximum(100); //the volume is between 0 and 100 _volumeSlider->setToolTip("Audio slider"); // Note: if you use streaming, there is no ability to use the position slider _positionSlider=new QSlider(Qt::Horizontal,this); _positionSlider->setMaximum(POSITION_RESOLUTION); QVBoxLayout *layout = new QVBoxLayout; layout->addWidget(_videoWidget); layout->addWidget(_positionSlider); layout->addWidget(_volumeSlider); setLayout(layout); _isPlaying=false; poller=new QTimer(this); //Initialize an instance of vlc //a structure for the exception is neede for this initalization libvlc_exception_init(&_vlcexcep); //create a new libvlc instance _vlcinstance=libvlc_new(sizeof(vlc_args) / sizeof(vlc_args[0]), vlc_args,&_vlcexcep); //tricky calculation of the char space used raise (&_vlcexcep); // Create a media player playing environement _mp = libvlc_media_player_new (_vlcinstance, &_vlcexcep); raise (&_vlcexcep); //connect the two sliders to the corresponding slots (uses Qt's signal / slots technology) connect(poller, SIGNAL(timeout()), this, SLOT(updateInterface())); connect(_positionSlider, SIGNAL(sliderMoved(int)), this, SLOT(changePosition(int))); connect(_volumeSlider, SIGNAL(sliderMoved(int)), this, SLOT(changeVolume(int))); poller->start(100); //start timer to trigger every 100 ms the updateInterface slot } //desctructor Player::~Player() { /* Stop playing */ libvlc_media_player_stop (_mp, &_vlcexcep); /* Free the media_player */ libvlc_media_player_release (_mp); libvlc_release (_vlcinstance); raise (&_vlcexcep); } void Player::playFile(QString file) { //the file has to be in one of the following formats /perhaps a little bit outdated) /* [file://]filename Plain media file http://ip:port/file HTTP URL ftp://ip:port/file FTP URL mms://ip:port/file MMS URL screen:// Screen capture [dvd://][device][@raw_device] DVD device [vcd://][device] VCD device [cdda://][device] Audio CD device udp:[[<source address>]@[<bind address>][:<bind port>]] */ /* Create a new LibVLC media descriptor */ _m = libvlc_media_new (_vlcinstance, file.toAscii(), &_vlcexcep); raise(&_vlcexcep); libvlc_media_player_set_media (_mp, _m, &_vlcexcep); raise(&_vlcexcep); // /!\ Please note /!\ // // passing the widget to the lib shows vlc at which position it should show up // vlc automatically resizes the video to the ´given size of the widget // and it even resizes it, if the size changes at the playing /* Get our media instance to use our window */ #if defined(Q_OS_WIN) libvlc_media_player_set_drawable(_mp, reinterpret_cast<unsigned int>(_videoWidget->winId()), &_vlcexcep ); //libvlc_media_player_set_hwnd(_mp, _videoWidget->winId(), &_vlcexcep ); // for vlc 1.0 #elif defined(Q_OS_MAC) libvlc_media_player_set_drawable(_mp, _videoWidget->winId(), &_vlcexcep ); //libvlc_media_player_set_agl (_mp, _videoWidget->winId(), &_vlcexcep); // for vlc 1.0 #else //Linux libvlc_media_player_set_drawable(_mp, _videoWidget->winId(), &_vlcexcep ); //libvlc_media_player_set_xwindow(_mp, _videoWidget->winId(), &_vlcexcep ); // for vlc 1.0 #endif raise(&_vlcexcep); /* Play */ libvlc_media_player_play (_mp, &_vlcexcep ); raise(&_vlcexcep); _isPlaying=true; } void Player::changeVolume(int newVolume) { libvlc_exception_clear(&_vlcexcep); libvlc_audio_set_volume (_vlcinstance,newVolume , &_vlcexcep); raise(&_vlcexcep); } void Player::changePosition(int newPosition) { libvlc_exception_clear(&_vlcexcep); // It's possible that the vlc doesn't play anything // so check before libvlc_media_t *curMedia = libvlc_media_player_get_media (_mp, &_vlcexcep); libvlc_exception_clear(&_vlcexcep); if (curMedia == NULL) return; float pos=(float)(newPosition)/(float)POSITION_RESOLUTION; libvlc_media_player_set_position (_mp, pos, &_vlcexcep); raise(&_vlcexcep); } void Player::updateInterface() { if(!_isPlaying) return; // It's possible that the vlc doesn't play anything // so check before libvlc_media_t *curMedia = libvlc_media_player_get_media (_mp, &_vlcexcep); libvlc_exception_clear(&_vlcexcep); if (curMedia == NULL) return; float pos=libvlc_media_player_get_position (_mp, &_vlcexcep); int siderPos=(int)(pos*(float)(POSITION_RESOLUTION)); _positionSlider->setValue(siderPos); int volume=libvlc_audio_get_volume (_vlcinstance,&_vlcexcep); _volumeSlider->setValue(volume); } void Player::raise(libvlc_exception_t * ex) { if (libvlc_exception_raised (ex)) { fprintf (stderr, "error: %s\n", libvlc_exception_get_message(ex)); exit (-1); } }
player.h
/* libVLC and Qt sample code * Copyright © 2009 Alexander Maringer <[email protected]> */ #ifndef VLC_ON_QT_H #define VLC_ON_QT_H #include <vlc/vlc.h> #include <QWidget> class QVBoxLayout; class QPushButton; class QTimer; class QFrame; class QSlider; #define POSITION_RESOLUTION 10000 class Player : public QWidget { Q_OBJECT QSlider *_positionSlider; QSlider *_volumeSlider; QFrame *_videoWidget; QTimer *poller; bool _isPlaying; libvlc_exception_t _vlcexcep; libvlc_instance_t *_vlcinstance; libvlc_media_player_t *_mp; libvlc_media_t *_m; public: Player(); ~Player(); void raise(libvlc_exception_t * ex); public slots: void playFile(QString file); void updateInterface(); void changeVolume(int newVolume); void changePosition(int newPosition); }; #endif
在新建立一个main.cpp 修改成如下
#include <QtGui/QApplication> #include "player.h" int main(int argc, char *argv[]) { QApplication a(argc, argv); Player p; p.resize(640,480); p.playFile("#填写你要播的文件路径#"); p.show(); return a.exec(); }
然后我们修改 .pro文件 成如下
TARGET = test1 TEMPLATE = app LIBS += -L'C:\vlc-lib' LIBS += -lvlc SOURCES += player.cpp \ main.cpp HEADERS += player.h
然后运行qmake
然后就可以编译了
编译成功以后想要运行,还必须把C:\vlc-lib里面的libvlc.dll,和libvlccore.dll拷贝到生成exe的目录里面才能运行
现在在qt creator里面就可以运行了(单独运行还需要其它dll)
haha