Phonon: Difference between revisions

    From KDE TechBase
    (Python example)
    (improving the code)
    Line 23: Line 23:
    = Using the phonon API =
    = Using the phonon API =
    The following example is taken from http://www.englishbreakfastnetwork.org/apidocs/apidox-kde-4.0/kdelibs-apidocs/phonon/html/index.html. It lets you choose a multimedia file and tries to play it. To change the sound device that is used by default, use the command <tt>systemsettings</tt>.
    The following example is taken from http://www.englishbreakfastnetwork.org/apidocs/apidox-kde-4.0/kdelibs-apidocs/phonon/html/index.html. It lets you choose a multimedia file and tries to play it. To change the sound device that is used by default, use the command <tt>systemsettings</tt>.
    == CMakeLists.txt ==
    You need a file CMakeLists.txt to compile the software later:
    CMakeLists.txt
    project (tutorial2)
    find_package(KDE4 REQUIRED)
    include (KDE4Defaults)
    include_directories(${KDE4_INCLUDES})
    set(tutorial1_SRCS tutorial2.cpp)
    kde4_add_executable(tutorial2 ${tutorial1_SRCS})
    target_link_libraries(tutorial2 ${KDE4_KDEUI_LIBS} phonon)
    install(TARGETS tutorial2  ${INSTALL_TARGETS_DEFAULT_ARGS})


    == tutorial2.cpp ==
    == tutorial2.cpp ==
    Line 29: Line 41:
         Copyright (C) 2007 Matthias Kretz <[email protected]>
         Copyright (C) 2007 Matthias Kretz <[email protected]>
         adapted 2008 by Thorsten Staerk
         adapted 2008 by Thorsten Staerk
     
         Permission to use, copy, modify, and distribute this software
         Permission to use, copy, modify, and distribute this software
         and its documentation for any purpose and without fee is hereby
         and its documentation for any purpose and without fee is hereby
    Line 38: Line 50:
         advertising or publicity pertaining to distribution of the
         advertising or publicity pertaining to distribution of the
         software without specific, written prior permission.
         software without specific, written prior permission.
     
         The author disclaim all warranties with regard to this
         The author disclaim all warranties with regard to this
         software, including all implied warranties of merchantability
         software, including all implied warranties of merchantability
    Line 57: Line 69:
    #include <QtGui/QDirModel>
    #include <QtGui/QDirModel>
    #include <QtGui/QColumnView>
    #include <QtGui/QColumnView>
    #include <QUrl>


    class MainWindow : public QMainWindow
    class MainWindow : public QMainWindow
    Line 63: Line 76:
         public:
         public:
             MainWindow();
             MainWindow();
        private slots:
            void play(const QModelIndex &index);


         private:
         private:
             void delayedInit();
             Phonon::MediaObject *m_media;
     
            QColumnView m_fileView;
            QDirModel m_model;


            Phonon::MediaObject *m_media;
    };
    };


    MainWindow::MainWindow()
    MainWindow::MainWindow()
        : m_fileView(this),
        m_media(0)
    {
    {
        setCentralWidget(&m_fileView);
    Phonon::MediaObject* media = new Phonon::MediaObject(this);
        m_fileView.setModel(&m_model);
    connect(media, SIGNAL(finished()), SLOT(slotFinished()));
        m_fileView.setFrameStyle(QFrame::NoFrame);
    media->setCurrentSource(QUrl("/tmp/video.mpg"));
     
    media->play();
        connect(&m_fileView, SIGNAL(updatePreviewWidget(const QModelIndex &)), SLOT(play(const QModelIndex &)));
    }
     
    void MainWindow::play(const QModelIndex &index)
    {
        delayedInit();
        m_media->setCurrentSource(m_model.filePath(index));
        m_media->play();
    }
     
    void MainWindow::delayedInit()
    {
        if (!m_media) {
            m_media = new Phonon::MediaObject(this);
            Phonon::AudioOutput *audioOutput = new Phonon::AudioOutput(Phonon::MusicCategory, this);
            createPath(m_media, audioOutput);
        }
    }
    }


    Line 116: Line 103:


    == Compile and run it ==
    == Compile and run it ==
      moc tutorial2.cpp > tutorial2.moc
      cmake . && make && ./tutorial2
    g++ -o tutorial -lphonon tutorial2.cpp && ./tutorial
     
    Eventually add a "-I/usr/include/qt4" to tell q++ where to look for the header files.


    [[Category:KDE4]]
    [[Category:KDE4]]
    [[Category:Phonon]]
    [[Category:Phonon]]

    Revision as of 13:43, 15 August 2010

    In order to make the revision process clear, I introduce a confident index, "0" means nobody except me has reviewed the text. I please the reviewers to increment the counter to prove the validity of the tutorials.

    You can get help on #phonon on irc.freenode.org.


    See Development/Tutorials/Phonon/Introduction/Python for the same example in Python.

    Introduction

    Confident Index =1

    The following is based on the documentation available here Phonon API.

    By getting involved with Phonon, you can choose between three different main tasks.

    • Using the Phonon API, which allows you to develop your own multimedia application. In fact any application which needs sound can take benefits from the phonon API. In the tutorials showing the API we will learn how to set up the development environment with kdevelop 3.4.
    • Hacking the Phonon library, (try to develop more this topic).
    • Writing Phonon backend, this consists in writing interfaces that allows Phonon to use different sound/video engine. This usually requires good skills and knowledge of the engine you interface with.

    Beginners will probably be more interested by the first task.

    Using the phonon API

    The following example is taken from http://www.englishbreakfastnetwork.org/apidocs/apidox-kde-4.0/kdelibs-apidocs/phonon/html/index.html. It lets you choose a multimedia file and tries to play it. To change the sound device that is used by default, use the command systemsettings.

    CMakeLists.txt

    You need a file CMakeLists.txt to compile the software later:

    CMakeLists.txt
    project (tutorial2)
    find_package(KDE4 REQUIRED)
    include (KDE4Defaults)
    include_directories(${KDE4_INCLUDES})
    set(tutorial1_SRCS tutorial2.cpp)
    kde4_add_executable(tutorial2 ${tutorial1_SRCS})
    target_link_libraries(tutorial2 ${KDE4_KDEUI_LIBS} phonon)
    install(TARGETS tutorial2  ${INSTALL_TARGETS_DEFAULT_ARGS})
    

    tutorial2.cpp

    /*   This file is part of the KDE project
         Copyright (C) 2007 Matthias Kretz <[email protected]>
         adapted 2008 by Thorsten Staerk
    
         Permission to use, copy, modify, and distribute this software
         and its documentation for any purpose and without fee is hereby
         granted, provided that the above copyright notice appear in all
         copies and that both that the copyright notice and this
         permission notice and warranty disclaimer appear in supporting
         documentation, and that the name of the author not be used in
         advertising or publicity pertaining to distribution of the
         software without specific, written prior permission.
    
         The author disclaim all warranties with regard to this
         software, including all implied warranties of merchantability
         and fitness.  In no event shall the author be liable for any
         special, indirect or consequential damages or any damages
         whatsoever resulting from loss of use, data or profits, whether
         in an action of contract, negligence or other tortious action,
         arising out of or in connection with the use or performance of
         this software.
    */
    
    #include <phonon/mediaobject.h>
    #include <phonon/path.h>
    #include <phonon/audiooutput.h>
    
    #include <QtGui/QApplication>
    #include <QtGui/QMainWindow>
    #include <QtGui/QDirModel>
    #include <QtGui/QColumnView>
    #include <QUrl>
    
    class MainWindow : public QMainWindow
    {
        Q_OBJECT
        public:
            MainWindow();
    
        private:
            Phonon::MediaObject *m_media;
    
    };
    
    MainWindow::MainWindow()
    {
     Phonon::MediaObject* media = new Phonon::MediaObject(this);
     connect(media, SIGNAL(finished()), SLOT(slotFinished()));
     media->setCurrentSource(QUrl("/tmp/video.mpg"));
     media->play();
    }
    
    int main(int argc, char **argv)
    {
        QApplication app(argc, argv);
        QApplication::setApplicationName("Phonon Tutorial 2");
        MainWindow mw;
        mw.show();
        return app.exec();
    }
    
    #include "tutorial2.moc"
    

    Compile and run it

    cmake . && make && ./tutorial2