Phonon - audio-output-problem and high latency

[nearlyNERD]

Hey,

after many problems, I get phonon "working":

When I click on an area, a 1-second-sound should be played.

My problem is, that I get this warnings and a big latency (1 second or something like this), before playing the sound:

WARNING: Phonon needs QCoreApplication::applicationName to be set to export audio output names through the DBUS interface 
Qt Application(5432) Phonon::KdePlatformPlugin::createBackend: using backend:  "Xine"

WARNING: Phonon needs QCoreApplication::applicationName to be set to export audio output names through the DBUS interface 
Qt Application(5432) Phonon::KdePlatformPlugin::createBackend: using backend:  "Xine"

To copy to clipboard, switch view to plain text mode 

My Phonon-specific code is this:

#include <phonon/audiooutput.h>
#include <phonon/path.h>
#include <phonon/mediaobject.h>
#include <phonon/backendcapabilities.h>
 
// .....
 
    Phonon::MediaObject *music =
         Phonon::createPlayer(Phonon::MusicCategory,
                              Phonon::MediaSource("/home/fabi/Desktop/MobileDrumKit/MobileDrumKit/data/Music/15575_lewis_crash_bell.wav"));
     music->play();

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

// .....

    Phonon::MediaObject *music =
         Phonon::createPlayer(Phonon::MusicCategory,
                              Phonon::MediaSource("/home/fabi/Desktop/MobileDrumKit/MobileDrumKit/data/Music/15575_lewis_crash_bell.wav"));
     music->play();

To copy to clipboard, switch view to plain text mode 

I also tried to do this :

QList<Phonon::AudioOutputDevice> audioOutputDevices =
    Phonon::BackendCapabilities::availableAudioOutputDevices();
    Phonon::AudioOutput *audioOutput = new Phonon::AudioOutput;
 
    audioOutput->setOutputDevice(audioOutputDevices[0]);

QList<Phonon::AudioOutputDevice> audioOutputDevices =
    Phonon::BackendCapabilities::availableAudioOutputDevices();
    Phonon::AudioOutput *audioOutput = new Phonon::AudioOutput;

    audioOutput->setOutputDevice(audioOutputDevices[0]);

To copy to clipboard, switch view to plain text mode 

but no luck...

Thanks in advance.

Also, I want to know, how big the latency between clicking and hear the sound is usually.

[nearlyNERD]

Isn't there anybody out, who knows, why I have these problems?

[Nickolay]

I also have this big latency, but only before first click! Seems on first click phonon loads all it's dlls,
and next clicks play immediately.
Who knows maybe is any possibility to "pre-initialize" phonon on start of application?

[viniciusjl]

Just for documentation, the link http://www.tuxradar.com/content/code...e-media-player has a solution for this problem:

The error you describe is because Phonon is expecting the application to have a name defined through the Qt framework. This can be solved by adding:

a.setApplicationName( "Mu" );

to the 'main.cpp' file, just below the 'QApplication a(argc, argv)' line.