Difference between revisions of "LibVLC SampleCode Qt"

From VideoLAN Wiki
Jump to navigation Jump to search
(Initial Release)
m (User request, +{{Outdated}})
 
(35 intermediate revisions by 15 users not shown)
Line 1: Line 1:
 +
{{Lowercase}}
 +
{{Example code|for=libVLC}}
 +
{{Outdated}}
 +
 
This sample code will render a video into a  Qt QWidget.  
 
This sample code will render a video into a  Qt QWidget.  
  
−
This was tested with vlc-0.9.9 and Qt 4.5.1 on WinXP.
+
This was tested with vlc-0.9.9 and Qt 4.5.1 on WinXP and Linux
 +
 
 +
This was tested with vlc-1.1.9 and Qt 4.7.2 and Ubuntu 11.04
 +
 
 +
== How to use? ==
 +
 
 +
 +
You need [[LibVLC|''libvlc headers'']] and ''Qt headers''.Take those 3 files, put them in a folder.
 +
Run
 +
qmake -project
 +
 
 +
Edit the .pro file and add
 +
LIBS += -L*path to vlc lib* #if you are at windows os
 +
LIBS += -lvlc
 +
 
 +
Run
 +
qmake
 +
and then
 +
make or mingw32-make under a Windows OS
 +
 
 +
 
 +
On win os you have to use the zip file. the lib and the header files are located in the sdk-folder.
 +
 
 +
== Notes ==
 +
 
 +
Depending on your distribution and the way you install Qt and Vlc it may be a good idea to reset the vlc's module cache:
 +
    sudo /usr/lib/vlc/vlc-cache-gen -f /usr/lib/vlc/plugins/
 +
or:
 +
  vlc --reset-plugins-cache
  
 +
== VLC 1.1.5 and Ubuntu Lucid ==
 +
[Rafael Capucho<rafael.capucho@gmail.com> 20120713] Modified to include properly QX11EmbedContainer header that was missing.- tested ok
 +
 +
[Ondrej Spilka 20101201] slightly modified for the modest versions...
 +
- X11 embed container have to be used, therefore QX11EmbedContainer rather than QFrame have to be used.- tested ok
 +
 +
 +
== Files ==
  
 
main.cpp:
 
main.cpp:
−
<pre>
+
<syntaxhighlight lang="cpp-qt">
 
/* libVLC and Qt sample code
 
/* libVLC and Qt sample code
 
  * Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 
  * Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
Line 18: Line 58:
 
     Player p;
 
     Player p;
 
     p.resize(640,480);
 
     p.resize(640,480);
−
     p.playFile("rtp://@:2626");
+
     p.playFile("rtp://@:2626"); // Replace with what you want to play
 
     p.show();
 
     p.show();
 
     return a.exec();
 
     return a.exec();
 
}
 
}
−
</pre>
+
</syntaxhighlight>
  
  
 
vlc_on_qt.h:
 
vlc_on_qt.h:
−
<pre>
+
<syntaxhighlight lang="cpp-qt">
 
/* libVLC and Qt sample code
 
/* libVLC and Qt sample code
 
  * Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 
  * Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
Line 36: Line 76:
  
 
#include <QWidget>
 
#include <QWidget>
 +
#include <QX11EmbedContainer>
  
−
class QProcess;
 
 
class QVBoxLayout;
 
class QVBoxLayout;
−
class QWidget;
 
−
class QSizePolicy;
 
 
class QPushButton;
 
class QPushButton;
−
class QTextEdit;
 
−
class QCloseEvent;
 
 
class QTimer;
 
class QTimer;
−
class QDebug;
 
 
class QFrame;
 
class QFrame;
 
class QSlider;
 
class QSlider;
Line 56: Line 91:
 
     QSlider *_positionSlider;
 
     QSlider *_positionSlider;
 
     QSlider *_volumeSlider;
 
     QSlider *_volumeSlider;
 +
    // [20101201 Ondra Spilka]
 +
    // on Linux/Ubuntu Lucid and VLC >= 1.0 (at least 1.1.5 was tested) XWindow handle have to be passed
 +
    // therefore QX11EmbedContainer have to be used instead of QFrame
 +
#ifdef Q_WS_X11   
 +
    QX11EmbedContainer *_videoWidget;
 +
#else
 
     QFrame *_videoWidget;
 
     QFrame *_videoWidget;
 +
#endif 
 
     QTimer *poller;
 
     QTimer *poller;
 
     bool _isPlaying;
 
     bool _isPlaying;
Line 63: Line 105:
 
     libvlc_media_player_t *_mp;
 
     libvlc_media_player_t *_mp;
 
     libvlc_media_t *_m;
 
     libvlc_media_t *_m;
−
    libvlc_media_list_t *_ml;
 
−
    libvlc_media_list_player_t * _mlp;
 
  
 
public:
 
public:
Line 79: Line 119:
 
};
 
};
 
#endif
 
#endif
−
</pre>
+
</syntaxhighlight>
 +
 
 +
 
 +
vlc_on_qt.cpp:
 +
<syntaxhighlight lang="cpp-qt">
 +
/* libVLC and Qt sample code
 +
* Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 +
*/
 +
#include "vlc_on_qt.h"
 +
 
 +
#include <QX11EmbedContainer>
 +
#include <QVBoxLayout>
 +
#include <QPushButton>
 +
#include <QSlider>
 +
#include <QTimer>
 +
#include <QFrame>
 +
 
 +
Player::Player()
 +
: QWidget()
 +
{
 +
    //preparation of the vlc command
 +
    const char * const vlc_args[] = {
 +
              "--verbose=2", //be much more verbose then normal for debugging purpose
 +
              "--plugin-path=C:\\vlc-0.9.9-win32\\plugins\\" };
 +
 
 +
#ifdef Q_WS_X11   
 +
    _videoWidget=new QX11EmbedContainer(this);
 +
#else
 +
    _videoWidget=new QFrame(this);
 +
#endif 
 +
 
 +
    _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
 +
        //[20101201 Ondrej Spilka] obsolete call on libVLC >=1.1.5
 +
        //libvlc_media_player_set_drawable(_mp, _videoWidget->winId(), &_vlcexcep );
 +
        //libvlc_media_player_set_xwindow(_mp, _videoWidget->winId(), &_vlcexcep ); // for vlc 1.0
 +
 
 +
    /* again note X11 handle on Linux is needed
 +
        winID() returns X11 handle when QX11EmbedContainer us used */
 +
   
 +
        int windid = _videoWidget->winId();
 +
        libvlc_media_player_set_xwindow (mp, windid );
 +
 
 +
    #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);
 +
    }
 +
}
 +
</syntaxhighlight>
 +
 
 +
== VLC 1.2 and OpenSuse 11.3 ==
 +
[Rafael Capucho<rafael.capucho@gmail.com> 20120713] Modified to include properly QX11EmbedContainer header that was missing.- tested ok
 +
 
 +
[Jofre Guevara 20101215] Modifications of original template based on new VLC version.
 +
 
 +
[Ondrej Spilka 20101201] slightly modified for the modest versions...
 +
 
 +
== Files ==
 +
 
 +
main.cpp:
 +
<syntaxhighlight lang="cpp-qt">
 +
/* libVLC and Qt sample code
 +
* Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 +
*/�
 +
 
 +
#include "vlc_on_qt.h"
 +
#include <QtGui/QApplication>
 +
 
 +
int main(int argc, char *argv[])
 +
{
 +
    QApplication a(argc, argv);
 +
    Player p;
 +
    p.resize(640,480);
 +
    p.playFile("rtp://@:2626"); // Replace with what you want to play
 +
    p.show();
 +
    return a.exec();
 +
}
 +
</syntaxhighlight>
 +
 
 +
 
 +
vlc_on_qt.h:
 +
<syntaxhighlight lang="cpp-qt">
 +
/* libVLC and Qt sample code
 +
* Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 +
*/
 +
#ifndef VLC_ON_QT_H
 +
#define VLC_ON_QT_H
 +
 
 +
#include <vlc/vlc.h>
 +
 
 +
#include <QX11EmbedContainer>
 +
#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;
 +
    // [20101215 JG]
 +
    // Tested on Linux OpenSuse and VLC 1.2.0. This version of VLC is not completely compatible with previous versions of VLC.
 +
    // [20101201 Ondra Spilka]
 +
    // on Linux/Ubuntu Lucid and VLC >= 1.0 (at least 1.1.5 was tested) XWindow handle have to be passed
 +
    // therefore QX11EmbedContainer have to be used instead of QFrame
 +
#ifdef Q_WS_X11
 +
    QX11EmbedContainer *_videoWidget;
 +
#else
 +
    QFrame *_videoWidget;
 +
#endif
 +
    // [20101215 JG] If KDE is used like unique desktop environment, only use QFrame *_videoWidget;
 +
    QTimer *poller;
 +
    bool _isPlaying;
 +
    //libvlc_exception_t _vlcexcep; // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    libvlc_instance_t *_vlcinstance;
 +
    libvlc_media_player_t *_mp;
 +
    libvlc_media_t *_m;
 +
 
 +
public:
 +
    Player();
 +
    ~Player();
 +
    //void raise(libvlc_exception_t * ex); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
 
 +
public slots:
 +
    void playFile(QString file);
 +
    void updateInterface();
 +
    void changeVolume(int newVolume);
 +
    void changePosition(int newPosition);
 +
 
 +
};
 +
#endif
 +
</syntaxhighlight>
 +
 
 +
 
 +
vlc_on_qt.cpp:
 +
<syntaxhighlight lang="cpp-qt">
 +
/* libVLC and Qt sample code
 +
* Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 +
*/
 +
#include "vlc_on_qt.h"
 +
 
 +
#include <QX11EmbedContainer>
 +
#include <QVBoxLayout>
 +
#include <QPushButton>
 +
#include <QSlider>
 +
#include <QTimer>
 +
#include <QFrame>
 +
 
 +
Player::Player()
 +
: QWidget()
 +
{
 +
    //preparation of the vlc command
 +
    const char * const vlc_args[] = {
 +
              "--verbose=2", //be much more verbose then normal for debugging purpose
 +
};
 +
 
 +
#ifdef Q_WS_X11
 +
    _videoWidget=new QX11EmbedContainer(this);
 +
#else
 +
    _videoWidget=new QFrame(this);
 +
#endif
 +
    // [20101215 JG] If KDE is used like unique desktop environment, only use _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); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
 
 +
    //create a new libvlc instance
 +
    _vlcinstance=libvlc_new(sizeof(vlc_args) / sizeof(vlc_args[0]), vlc_args);  //tricky calculation of the char space used
 +
    //_vlcinstance=libvlc_new(sizeof(vlc_args) / sizeof(vlc_args[0]), vlc_args,&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    //raise (&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
 
 +
    // Create a media player playing environement
 +
    _mp = libvlc_media_player_new (_vlcinstance);
 +
    //_mp = libvlc_media_player_new (_vlcinstance, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    //raise (&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
 
 +
    //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);
 +
    //libvlc_media_player_stop (_mp, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
 
 +
    /* Free the media_player */
 +
    libvlc_media_player_release (_mp);
 +
 
 +
    libvlc_release (_vlcinstance);
 +
    //raise (&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
}
 +
 
 +
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_path(_vlcinstance, file.toAscii());
 +
    //_m = libvlc_media_new (_vlcinstance, file.toAscii(), &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
 
 +
    libvlc_media_player_set_media (_mp, _m);
 +
    //libvlc_media_player_set_media (_mp, _m, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
 
 +
    // /!\ 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()));
 +
        //libvlc_media_player_set_drawable(_mp, reinterpret_cast<unsigned int>(_videoWidget->winId()), &_vlcexcep ); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
        //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());
 +
        //libvlc_media_player_set_drawable(_mp, _videoWidget->winId(), &_vlcexcep ); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
        //libvlc_media_player_set_agl (_mp, _videoWidget->winId(), &_vlcexcep); // for vlc 1.0
 +
    #else //Linux
 +
        //[20101201 Ondrej Spilka] obsolete call on libVLC >=1.1.5
 +
        //libvlc_media_player_set_drawable(_mp, _videoWidget->winId(), &_vlcexcep );
 +
        //libvlc_media_player_set_xwindow(_mp, _videoWidget->winId(), &_vlcexcep ); // for vlc 1.0
 +
 
 +
    /* again note X11 handle on Linux is needed
 +
        winID() returns X11 handle when QX11EmbedContainer us used */
 +
 
 +
        int windid = _videoWidget->winId();
 +
        libvlc_media_player_set_xwindow (_mp, windid );
 +
 
 +
    #endif
 +
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
 
 +
    /* Play */
 +
    libvlc_media_player_play (_mp);
 +
    //libvlc_media_player_play (_mp, &_vlcexcep ); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
 
 +
    _isPlaying=true;
 +
}
 +
 
 +
void Player::changeVolume(int newVolume)
 +
{
 +
    //libvlc_exception_clear(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    libvlc_audio_set_volume (_mp,newVolume);
 +
    //libvlc_audio_set_volume (_vlcinstance,newVolume , &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
}
 +
 
 +
void Player::changePosition(int newPosition)
 +
{
 +
    //libvlc_exception_clear(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    // It's possible that the vlc doesn't play anything
 +
    // so check before
 +
    libvlc_media_t *curMedia = libvlc_media_player_get_media (_mp);
 +
    //libvlc_media_t *curMedia = libvlc_media_player_get_media (_mp, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    //libvlc_exception_clear(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    if (curMedia == NULL)
 +
        return;
 +
 
 +
    float pos=(float)(newPosition)/(float)POSITION_RESOLUTION;
 +
    libvlc_media_player_set_position (_mp, pos);
 +
    //libvlc_media_player_set_position (_mp, pos, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
}
 +
 
 +
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);
 +
    //libvlc_media_t *curMedia = libvlc_media_player_get_media (_mp, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    //libvlc_exception_clear(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    if (curMedia == NULL)
 +
        return;
 +
 
 +
    float pos=libvlc_media_player_get_position (_mp);
 +
    //float pos=libvlc_media_player_get_position (_mp, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    int siderPos=(int)(pos*(float)(POSITION_RESOLUTION));
 +
    _positionSlider->setValue(siderPos);
 +
    int volume=libvlc_audio_get_volume (_mp);
 +
    //int volume=libvlc_audio_get_volume (_vlcinstance,&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
    _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);
 +
    }
 +
}*/  // [20101215 JG] Used for versions prior to VLC 1.2.0.
 +
</syntaxhighlight>
 +
 
 +
[[Category:libVLC]]
 +
[[Category:Qt]]

Latest revision as of 05:46, 17 March 2019

This page contains example code for libVLC.
This page is outdated and information might be incorrect.
Create an account to start editing, and then click here to update this article.

This sample code will render a video into a Qt QWidget.

This was tested with vlc-0.9.9 and Qt 4.5.1 on WinXP and Linux

This was tested with vlc-1.1.9 and Qt 4.7.2 and Ubuntu 11.04

How to use?

You need libvlc headers and Qt headers.Take those 3 files, put them in a folder. Run 

qmake -project

Edit the .pro file and add 

LIBS += -L*path to vlc lib* #if you are at windows os
LIBS += -lvlc

Run 

qmake

and then 

make or mingw32-make under a Windows OS


On win os you have to use the zip file. the lib and the header files are located in the sdk-folder.

Notes

Depending on your distribution and the way you install Qt and Vlc it may be a good idea to reset the vlc's module cache: 

   sudo /usr/lib/vlc/vlc-cache-gen -f /usr/lib/vlc/plugins/

or: 

  vlc --reset-plugins-cache

VLC 1.1.5 and Ubuntu Lucid

[Rafael Capucho<rafael.capucho@gmail.com> 20120713] Modified to include properly QX11EmbedContainer header that was missing.- tested ok

[Ondrej Spilka 20101201] slightly modified for the modest versions... - X11 embed container have to be used, therefore QX11EmbedContainer rather than QFrame have to be used.- tested ok


Files

main.cpp: 

/* libVLC and Qt sample code
 * Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 */

#include "vlc_on_qt.h"
#include <QtGui/QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Player p;
    p.resize(640,480);
    p.playFile("rtp://@:2626"); // Replace with what you want to play
    p.show();
    return a.exec();
}


vlc_on_qt.h: 

/* libVLC and Qt sample code
 * Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 */
#ifndef VLC_ON_QT_H
#define VLC_ON_QT_H

#include <vlc/vlc.h>

#include <QWidget>
#include <QX11EmbedContainer>

class QVBoxLayout;
class QPushButton;
class QTimer;
class QFrame;
class QSlider;

#define POSITION_RESOLUTION 10000

class Player : public QWidget
{
    Q_OBJECT
    QSlider *_positionSlider;
    QSlider *_volumeSlider;
    // [20101201 Ondra Spilka] 
    // on Linux/Ubuntu Lucid and VLC >= 1.0 (at least 1.1.5 was tested) XWindow handle have to be passed
    // therefore QX11EmbedContainer have to be used instead of QFrame
#ifdef Q_WS_X11    
    QX11EmbedContainer *_videoWidget;
#else
    QFrame *_videoWidget;
#endif   
    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


vlc_on_qt.cpp: 

/* libVLC and Qt sample code
 * Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 */
#include "vlc_on_qt.h"

#include <QX11EmbedContainer>
#include <QVBoxLayout>
#include <QPushButton>
#include <QSlider>
#include <QTimer>
#include <QFrame>

Player::Player()
: QWidget()
{
    //preparation of the vlc command
    const char * const vlc_args[] = {
              "--verbose=2", //be much more verbose then normal for debugging purpose
              "--plugin-path=C:\\vlc-0.9.9-win32\\plugins\\" };

#ifdef Q_WS_X11    
    _videoWidget=new QX11EmbedContainer(this);
#else
    _videoWidget=new QFrame(this);
#endif   

    _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
        //[20101201 Ondrej Spilka] obsolete call on libVLC >=1.1.5 
        //libvlc_media_player_set_drawable(_mp, _videoWidget->winId(), &_vlcexcep );
        //libvlc_media_player_set_xwindow(_mp, _videoWidget->winId(), &_vlcexcep ); // for vlc 1.0

     /* again note X11 handle on Linux is needed
        winID() returns X11 handle when QX11EmbedContainer us used */
     
        int windid = _videoWidget->winId();
        libvlc_media_player_set_xwindow (mp, windid );

    #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);
    }
}

VLC 1.2 and OpenSuse 11.3

[Rafael Capucho<rafael.capucho@gmail.com> 20120713] Modified to include properly QX11EmbedContainer header that was missing.- tested ok

[Jofre Guevara 20101215] Modifications of original template based on new VLC version.

[Ondrej Spilka 20101201] slightly modified for the modest versions...

Files

main.cpp: 

/* libVLC and Qt sample code
 * Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 */�

#include "vlc_on_qt.h"
#include <QtGui/QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Player p;
    p.resize(640,480);
    p.playFile("rtp://@:2626"); // Replace with what you want to play
    p.show();
    return a.exec();
}


vlc_on_qt.h: 

/* libVLC and Qt sample code
 * Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 */
#ifndef VLC_ON_QT_H
#define VLC_ON_QT_H

#include <vlc/vlc.h>

#include <QX11EmbedContainer>
#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;
    // [20101215 JG]
    // Tested on Linux OpenSuse and VLC 1.2.0. This version of VLC is not completely compatible with previous versions of VLC.
    // [20101201 Ondra Spilka]
    // on Linux/Ubuntu Lucid and VLC >= 1.0 (at least 1.1.5 was tested) XWindow handle have to be passed
    // therefore QX11EmbedContainer have to be used instead of QFrame
#ifdef Q_WS_X11
    QX11EmbedContainer *_videoWidget;
#else
    QFrame *_videoWidget;
#endif
    // [20101215 JG] If KDE is used like unique desktop environment, only use QFrame *_videoWidget;
    QTimer *poller;
    bool _isPlaying;
    //libvlc_exception_t _vlcexcep; // [20101215 JG] Used for versions prior to VLC 1.2.0.
    libvlc_instance_t *_vlcinstance;
    libvlc_media_player_t *_mp;
    libvlc_media_t *_m;

public:
    Player();
    ~Player();
    //void raise(libvlc_exception_t * ex); // [20101215 JG] Used for versions prior to VLC 1.2.0.

public slots:
    void playFile(QString file);
    void updateInterface();
    void changeVolume(int newVolume);
    void changePosition(int newPosition);

};
#endif


vlc_on_qt.cpp: 

/* libVLC and Qt sample code
 * Copyright © 2009 Alexander Maringer <maringer@maringer-it.de>
 */
#include "vlc_on_qt.h"

#include <QX11EmbedContainer>
#include <QVBoxLayout>
#include <QPushButton>
#include <QSlider>
#include <QTimer>
#include <QFrame>

Player::Player()
: QWidget()
{
    //preparation of the vlc command
    const char * const vlc_args[] = {
              "--verbose=2", //be much more verbose then normal for debugging purpose
 };

#ifdef Q_WS_X11
    _videoWidget=new QX11EmbedContainer(this);
#else
    _videoWidget=new QFrame(this);
#endif
    // [20101215 JG] If KDE is used like unique desktop environment, only use _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); // [20101215 JG] Used for versions prior to VLC 1.2.0.

    //create a new libvlc instance
    _vlcinstance=libvlc_new(sizeof(vlc_args) / sizeof(vlc_args[0]), vlc_args);  //tricky calculation of the char space used
    //_vlcinstance=libvlc_new(sizeof(vlc_args) / sizeof(vlc_args[0]), vlc_args,&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    //raise (&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.

    // Create a media player playing environement
    _mp = libvlc_media_player_new (_vlcinstance);
    //_mp = libvlc_media_player_new (_vlcinstance, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    //raise (&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.

    //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);
    //libvlc_media_player_stop (_mp, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.

    /* Free the media_player */
    libvlc_media_player_release (_mp);

    libvlc_release (_vlcinstance);
    //raise (&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
}

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_path(_vlcinstance, file.toAscii());
    //_m = libvlc_media_new (_vlcinstance, file.toAscii(), &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.

    libvlc_media_player_set_media (_mp, _m);
    //libvlc_media_player_set_media (_mp, _m, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.

    // /!\ 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()));
        //libvlc_media_player_set_drawable(_mp, reinterpret_cast<unsigned int>(_videoWidget->winId()), &_vlcexcep ); // [20101215 JG] Used for versions prior to VLC 1.2.0.
        //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());
        //libvlc_media_player_set_drawable(_mp, _videoWidget->winId(), &_vlcexcep ); // [20101215 JG] Used for versions prior to VLC 1.2.0.
        //libvlc_media_player_set_agl (_mp, _videoWidget->winId(), &_vlcexcep); // for vlc 1.0
    #else //Linux
        //[20101201 Ondrej Spilka] obsolete call on libVLC >=1.1.5
        //libvlc_media_player_set_drawable(_mp, _videoWidget->winId(), &_vlcexcep );
        //libvlc_media_player_set_xwindow(_mp, _videoWidget->winId(), &_vlcexcep ); // for vlc 1.0

     /* again note X11 handle on Linux is needed
        winID() returns X11 handle when QX11EmbedContainer us used */

        int windid = _videoWidget->winId();
        libvlc_media_player_set_xwindow (_mp, windid );

    #endif
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.

    /* Play */
    libvlc_media_player_play (_mp);
    //libvlc_media_player_play (_mp, &_vlcexcep ); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.

    _isPlaying=true;
}

void Player::changeVolume(int newVolume)
{
    //libvlc_exception_clear(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    libvlc_audio_set_volume (_mp,newVolume);
    //libvlc_audio_set_volume (_vlcinstance,newVolume , &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
}

void Player::changePosition(int newPosition)
{
    //libvlc_exception_clear(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    // It's possible that the vlc doesn't play anything
    // so check before
    libvlc_media_t *curMedia = libvlc_media_player_get_media (_mp);
    //libvlc_media_t *curMedia = libvlc_media_player_get_media (_mp, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    //libvlc_exception_clear(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    if (curMedia == NULL)
        return;

    float pos=(float)(newPosition)/(float)POSITION_RESOLUTION;
    libvlc_media_player_set_position (_mp, pos);
    //libvlc_media_player_set_position (_mp, pos, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    //raise(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
}

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);
    //libvlc_media_t *curMedia = libvlc_media_player_get_media (_mp, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    //libvlc_exception_clear(&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    if (curMedia == NULL)
        return;

    float pos=libvlc_media_player_get_position (_mp);
    //float pos=libvlc_media_player_get_position (_mp, &_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    int siderPos=(int)(pos*(float)(POSITION_RESOLUTION));
    _positionSlider->setValue(siderPos);
    int volume=libvlc_audio_get_volume (_mp);
    //int volume=libvlc_audio_get_volume (_vlcinstance,&_vlcexcep); // [20101215 JG] Used for versions prior to VLC 1.2.0.
    _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);
    }
}*/  // [20101215 JG] Used for versions prior to VLC 1.2.0.
Retrieved from "https://wiki.videolan.org/index.php?title=LibVLC_SampleCode_Qt&oldid=59853"