Phonon: Difference between revisions

From KDE TechBase
m (→‎Make And Run: fix naming)
(36 intermediate revisions by 4 users not shown)
Line 1: Line 1:
These tutorials are now under construction, please be patient. 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.
If you are a Phonon developer and you realize errors, you're missing some details or a whole chapter. Please feel free to complete the followings.
You can get help on #phonon on irc.freenode.org.
----
= 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.  
* '''Using the Phonon API''', which allows you to develop your own multimedia application. '''This is discussed here.'''
 
* '''Hacking the Phonon library'''.
* '''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.
* '''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.
=Abstract=
 
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>.
= 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.
 
== tutorial2.cpp ==
<pre>
/*  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.
*/


=The Code=
All the code we need will be in one file, <tt>main.cpp</tt>. Create that file with the code below:
<syntaxhighlight lang="cpp-qt">
#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>
#include <QUrl>
#include <QtGui/QColumnView>


class MainWindow : public QMainWindow
class MainWindow : public QMainWindow
Line 62: Line 24:
     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);
     Phonon::MediaObject* media = new Phonon::MediaObject(this);
    m_fileView.setModel(&m_model);
    Phonon::createPath(media, new Phonon::AudioOutput(Phonon::MusicCategory, this));
    m_fileView.setFrameStyle(QFrame::NoFrame);
    media->setCurrentSource(QFileDialog::getOpenFileName(0,QString("Select a file to play"),QString()));
 
     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 111: Line 43:
}
}


#include "tutorial2.moc"
#include "main.moc"
</pre>
</syntaxhighlight>
 
=Build=
As usual, we use CMake for build operations:
 
== CMakeLists.txt ==
You need a file CMakeLists.txt to compile the software:
<syntaxhighlight lang="cmake">
project (phonon_tutorial1)
find_package(KDE4 REQUIRED)
include (KDE4Defaults)
include_directories(${KDE4_INCLUDES})
set(phonon_tutorial1_SRCS main.cpp)
kde4_add_executable(phonon_tutorial1 ${phonon_tutorial1_SRCS})
target_link_libraries(phonon_tutorial1 ${KDE4_KDEUI_LIBS} ${PHONON_LIBS})
install(TARGETS phonon_tutorial1  ${INSTALL_TARGETS_DEFAULT_ARGS})
</syntaxhighlight>
 
==Make And Run==
<syntaxhighlight lang="bash">
cmake . && make && ./phonon_tutorial1
</syntaxhighlight>
 
= Getting More Help =
To talk among phonon experts, point your irc client to the server irc.freenode.org, channel #phonon.


== Compile and run it ==
= See Also =
moc tutorial2.cpp > tutorial2.moc
* [[Development/Tutorials/Phonon/Introduction/Python]] - same example in Python
g++ -o tutorial -lphonon tutorial2.cpp && ./tutorial


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

Revision as of 23:16, 10 May 2013

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.

Abstract

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.

The Code

All the code we need will be in one file, main.cpp. Create that file with the code below: 

#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"

Build

As usual, we use CMake for build operations:

CMakeLists.txt

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

project (phonon_tutorial1)
find_package(KDE4 REQUIRED)
include (KDE4Defaults)
include_directories(${KDE4_INCLUDES})
set(phonon_tutorial1_SRCS main.cpp)
kde4_add_executable(phonon_tutorial1 ${phonon_tutorial1_SRCS})
target_link_libraries(phonon_tutorial1 ${KDE4_KDEUI_LIBS} ${PHONON_LIBS})
install(TARGETS phonon_tutorial1  ${INSTALL_TARGETS_DEFAULT_ARGS})

Make And Run

cmake . && make && ./phonon_tutorial1

Getting More Help

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

See Also

Retrieved from "https://techbase.kde.org/index.php?title=Phonon&oldid=79296"