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

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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.
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{{Infobox tutorial|time=20 min|distribution=SUSE Linux 11.4|type=Howto|happyreaders=2|unhappyreaders=0}}
 
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You can get help on #phonon on irc.freenode.org.
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----
+
  
 
= Introduction =
 
= Introduction =
''Confident Index =0''
 
 
The following is based on the documentation available here
 
[http://www.englishbreakfastnetwork.org/apidocs/apidox-kde-4.0/kdelibs-apidocs/phonon/html/index.html Phonon API].
 
 
 
By getting involved with Phonon, you can choose between three different main tasks.
 
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.  
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* '''Using the Phonon API''', which allows you to develop your own multimedia application. '''This is discussed here.'''
  
* '''Hacking the Phonon library''', (try to develop more this topic).
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* '''Hacking the Phonon library'''.
  
 
* '''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.
 
* '''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 =
 
= 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>.
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The following example lets you select a music file and plays it. To change the sound device that is used by default, use the command <tt>systemsettings</tt>.
  
== tutorial2.cpp ==
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== CMakeLists.txt ==
 +
You need a file CMakeLists.txt to compile the software later:
 +
project (tutorial2)
 +
find_package(KDE4 REQUIRED)
 +
include (KDE4Defaults)
 +
include_directories(${KDE4_INCLUDES})
 +
set(tutorial1_SRCS main.cpp)
 +
kde4_add_executable(tutorial2 ${tutorial1_SRCS})
 +
target_link_libraries(tutorial2 ${KDE4_KDEUI_LIBS} phonon)
 +
install(TARGETS tutorial2  ${INSTALL_TARGETS_DEFAULT_ARGS})
 +
 
 +
== main.cpp ==
 
<pre>
 
<pre>
/*  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/mediaobject.h>
#include <phonon/path.h>
 
 
#include <phonon/audiooutput.h>
 
#include <phonon/audiooutput.h>
  
 +
#include <QFileDialog>
 
#include <QtGui/QApplication>
 
#include <QtGui/QApplication>
 
#include <QtGui/QMainWindow>
 
#include <QtGui/QMainWindow>
#include <QtGui/QDirModel>
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#include <QUrl>
#include <QtGui/QColumnView>
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class MainWindow : public QMainWindow
 
class MainWindow : public QMainWindow
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     public:
 
     public:
 
         MainWindow();
 
         MainWindow();
 
    private slots:
 
        void play(const QModelIndex &index);
 
 
    private:
 
        void delayedInit();
 
 
        QColumnView m_fileView;
 
        QDirModel m_model;
 
 
        Phonon::MediaObject *m_media;
 
 
};
 
};
  
 
MainWindow::MainWindow()
 
MainWindow::MainWindow()
    : m_fileView(this),
 
    m_media(0)
 
 
{
 
{
     setCentralWidget(&m_fileView);
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     Phonon::MediaObject* media = new Phonon::MediaObject(this);
    m_fileView.setModel(&m_model);
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    Phonon::createPath(media, new Phonon::AudioOutput(Phonon::MusicCategory, this));
    m_fileView.setFrameStyle(QFrame::NoFrame);
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    media->setCurrentSource(QFileDialog::getOpenFileName(0,QString("Select a file to play"),QString()));
 
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     media->play();
    connect(&m_fileView, SIGNAL(updatePreviewWidget(const QModelIndex &)), SLOT(play(const QModelIndex &)));
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}
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void MainWindow::play(const QModelIndex &index)
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{
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    delayedInit();
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    m_media->setCurrentSource(m_model.filePath(index));
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    m_media->play();
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}
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void MainWindow::delayedInit()
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{
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    if (!m_media) {
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        m_media = new Phonon::MediaObject(this);
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        Phonon::AudioOutput *audioOutput = new Phonon::AudioOutput(Phonon::MusicCategory, this);
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        createPath(m_media, audioOutput);
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     }
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}
 
}
  
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}
 
}
  
#include "tutorial2.moc"
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#include "main.moc"
 
</pre>
 
</pre>
  
 
== Compile and run it ==
 
== Compile and run it ==
  moc tutorial2.cpp > tutorial2.moc
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  cmake . && make && ./tutorial2
g++ -o tutorial -lphonon tutorial2.cpp && ./tutorial
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 +
= Getting more help =
 +
To talk among phonon experts, point your irc client to the server irc.freenode.org, channel #phonon.
 +
 
 +
= See also =
 +
* [[Development/Tutorials/Phonon/Introduction/Python]] - same example in Python
  
 
[[Category:KDE4]]
 
[[Category:KDE4]]
 
[[Category:Phonon]]
 
[[Category:Phonon]]
 +
[[Category:Tutorial]]

Revision as of 09:33, 26 September 2011


Tutorial Factbox
Time to replay 20 min
Example Distro SUSE Linux 11.4
Type Howto
Happy readers 2
Unhappy readers 0

Contents

Introduction

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. This is discussed here.
  • Hacking the Phonon library.
  • 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.

Using the phonon API

The following example lets you select a music file and plays 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:

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

main.cpp

#include <phonon/mediaobject.h>
#include <phonon/audiooutput.h>

#include <QFileDialog>
#include <QtGui/QApplication>
#include <QtGui/QMainWindow>
#include <QUrl>

class MainWindow : public QMainWindow
{
    Q_OBJECT
    public:
        MainWindow();
};

MainWindow::MainWindow()
{
    Phonon::MediaObject* media = new Phonon::MediaObject(this);
    Phonon::createPath(media, new Phonon::AudioOutput(Phonon::MusicCategory, this));
    media->setCurrentSource(QFileDialog::getOpenFileName(0,QString("Select a file to play"),QString()));
    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 "main.moc"

Compile and run it

cmake . && make && ./tutorial2

Getting more help

To talk among phonon experts, point your irc client to the server irc.freenode.org, channel #phonon.

See also


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