How to disable Phonon buffer ?

Hello,

I am using QT Phonon and FFserver to respecitvly display and stream a live video from a webcam.
My FFserver create an asf file (test.asf) on a http server running on computer A.
A Qt application (running on linux) get the test file and display it on screen.

If I start my QT Application at the time t=0s, during approximatively 3 seconds my VideoViewer will be a black rectangle, and then my camera stream will be displayed.
The image displayed is approximatively 3 seconds in the past...

That looks like if Phonon fill a buffer during 3 seconds, then start to display...

Why ? And how can I get disable the buffer ?

Here is my QT Code :

Code:

---

#include "A.h"
#include <QUrl>
using namespace Phonon;
 
A::A(QWidget *_parent)
:QWidget(_parent),
m_leftVP(NULL),
m_rightVP(NULL),
m_leftStream(NULL),
m_rightStream(NULL)
{
	m_leftVP = new VideoPlayer(Phonon::VideoCategory, this);
	sl_OnPlay();
}
 
A::~A(void)
{
	if(m_rightStream) delete m_rightStream;
	if(m_leftStream) delete m_leftStream;
}
 
void A::sl_OnPlay(void)
{
	QUrl leftFile("http://192.168.0.18:8090/test.asf");
	MediaSource src(leftFile);	
	m_leftVP->play(leftFile);
	m_leftVP->seek(m_leftVP->totalTime());
}

---

Here is my FFServer stream :

Code:

---

<Stream test.asf>
 Feed feed1.ffm
 Format asf
 VideoCodec msmpeg4v2
 VideoFrameRate 15
 VideoBufferSize 10
 VideoBitRate 200
 VideoQMin 1
 VideoQMax 5
 VideoSize 320x240
 PreRoll 0
 NoAudio
 VideoGopSize 12
 StartSendOnKey
 AVOptionsVideo flags +global_header
</Stream>

---

Cheers,

A.BARRAL