Difference between revisions of "Development/Tutorials/Phonon/Introduction"

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(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 <kretz@kde.org>
 
     Copyright (C) 2007 Matthias Kretz <kretz@kde.org>
 
     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 14:43, 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.

Contents

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 <kretz@kde.org>
     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

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