Problem with the QWidget::winId() method

[yellowmat]

Hi everybody,

As explain in the title, I (think I) have a problem with the QWidget::winId() method return value.

I am using mplayer to play movies in my application. I use the -wid argument to tell mplayer into which widget to display. I can hear sound but I can't see the video.

I did the followings tests :
* I try to run, in the command line, mplayer with the name of a movie file as the only argument ... it works fine because a window opens, and I can see the movie
* I try to do the same in my application, adding the -wid argument with the widget id ... I can hear sounds but can't see anything
* I use a specific background color for my widget in order to be sure it is shown when I request mplayer to play the movie ... I can see a square, with the specific background color where the movie (the widget itself) is supposed to be played so the widget is well shown

So, I don't understand why I can't see the movie.

Here is the code of my widget :
.h

#ifndef _WIDGET_VIDEO_H
#define _WIDGET_VIDEO_H
 
#include <qwidget.h>
 
class QString;
class QProcess;
 
class CWidgetVideo : public QWidget
{
public:
	CWidgetVideo(QWidget* parent=0, const char* name=0);
	~WidgetVideo();
 
public:
	void StartVideo(const QString& video);
	void StopVideo();
 
private:
	QProcess*	m_pProcessVideo;
};
#endif

#ifndef _WIDGET_VIDEO_H
#define _WIDGET_VIDEO_H

#include <qwidget.h>

class QString;
class QProcess;

class CWidgetVideo : public QWidget
{
public:
	CWidgetVideo(QWidget* parent=0, const char* name=0);
	~WidgetVideo();

public:
	void StartVideo(const QString& video);
	void StopVideo();

private:
	QProcess*	m_pProcessVideo;
};
#endif

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.cpp

#include "WidgetVideo.h"
#include <qapplication.h>
#include <qstring.h>
#include <qprocess.h>
 
CWidgetVideo::CWidgetVideo(QWidget* parent/*=0*/, const char* name/*=0*/):
QWidget(parent, name),
m_pProcessVideo(0)
{
}
 
CWidgetVideo::~CWidgetVideo()
{
	StopVideo();
}
 
void CWidgetVideo::StartVideo(const QString& video)
{
	setBackgroundColor(QColor(255, 0, 255));
 
	if( m_pProcessVideo )
		StopVideo();
 
	m_pProcessVideo = new QProcess( this );
 
	m_pProcessVideo->addArgument("C:\\MPLAYER\\mplayer.exe");
	m_pProcessVideo->addArgument("-wid");
	m_pProcessVideo->addArgument(QString::number((int)winId()));
	m_pProcessVideo->addArgument(video);
 
	if( !m_pProcessVideo->start() )
		qDebug("Impossible to start");
}
 
void CWidgetVideo::StopVideo()
{
	if( m_pProcessVideo )
	{
		m_pProcessVideo->tryTerminate();
 
		delete m_pProcessVideo;
		m_pProcessVideo = 0;
	}
}

#include "WidgetVideo.h"
#include <qapplication.h>
#include <qstring.h>
#include <qprocess.h>

CWidgetVideo::CWidgetVideo(QWidget* parent/*=0*/, const char* name/*=0*/):
QWidget(parent, name),
m_pProcessVideo(0)
{
}

CWidgetVideo::~CWidgetVideo()
{
	StopVideo();
}

void CWidgetVideo::StartVideo(const QString& video)
{
	setBackgroundColor(QColor(255, 0, 255));

	if( m_pProcessVideo )
		StopVideo();

	m_pProcessVideo = new QProcess( this );

	m_pProcessVideo->addArgument("C:\\MPLAYER\\mplayer.exe");
	m_pProcessVideo->addArgument("-wid");
	m_pProcessVideo->addArgument(QString::number((int)winId()));
	m_pProcessVideo->addArgument(video);

	if( !m_pProcessVideo->start() )
		qDebug("Impossible to start");
}

void CWidgetVideo::StopVideo()
{
	if( m_pProcessVideo )
	{
		m_pProcessVideo->tryTerminate();

		delete m_pProcessVideo;
		m_pProcessVideo = 0;
	}
}

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Finally the main application source code :

void TestMPlayerDialog::init()
{
	m_pPlayer = 0;
}
 
 
void TestMPlayerDialog::starting()
{
	QString directory = QDir::currentDirPath() + "/";
	QString video = QFileDialog::getOpenFileName(directory, "Video (*.avi *.wmv *.mpeg *.mov)", this, "", "");
 
	if( video != "" )
	{
		if( m_pPlayer )
		{
			delete m_pPlayer;
			m_pPlayer = 0;
		}
 
		m_pPlayer = new CWidgetVideo(this, "Player");
 
		m_pPlayer->setGeometry(10, 120, 320, 240);
		m_pPlayer->StartVideo(video);
		m_pPlayer->show();
	}
}
 
 
void TestMPlayerDialog::stopping()
{
	if( m_pPlayer )
	{
		m_pPlayer->StopVideo();
		m_pPlayer->hide();
 
		delete m_pPlayer;
		m_pPlayer = 0;
	}
}

void TestMPlayerDialog::init()
{
	m_pPlayer = 0;
}


void TestMPlayerDialog::starting()
{
	QString directory = QDir::currentDirPath() + "/";
	QString video = QFileDialog::getOpenFileName(directory, "Video (*.avi *.wmv *.mpeg *.mov)", this, "", "");

	if( video != "" )
	{
		if( m_pPlayer )
		{
			delete m_pPlayer;
			m_pPlayer = 0;
		}

		m_pPlayer = new CWidgetVideo(this, "Player");

		m_pPlayer->setGeometry(10, 120, 320, 240);
		m_pPlayer->StartVideo(video);
		m_pPlayer->show();
	}
}


void TestMPlayerDialog::stopping()
{
	if( m_pPlayer )
	{
		m_pPlayer->StopVideo();
		m_pPlayer->hide();

		delete m_pPlayer;
		m_pPlayer = 0;
	}
}

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starting and stopping are two slots called when buttons start and stop are pressed.

I hope someone could help me, thantks in advance.

[wysota]

You need to force OpenGL or DirectX output. Try adding a -vo gl2 (or -vo directx) option to mplayer.

[yellowmat]

I have already tryed with those two options without success :
* No sound and no video when forcing output to OpenGL
* No video when forving output to DirectX

It is strange because ... I'm not sure of that ... but the same application played video with success under Windows2000, but as I said, I'm not sure of that point.

[yellowmat]

I works now, since I tell mplayer to use directx as you advise me but I also specify the noaccel argument because it is the source of my problem ... I found it into the pages of mplayer.

Thanks for your help.

[MrShahi]

yes its is the problem of winId() because in window os QWidget->winId() return H_WND which makes problem to embed the mplayer within QWidget.....
I have the same problem. If any one can solve this problem please do it fast .I need your help..........
thanx in advance

[MrShahi]

hello guys .....I have solved this problem .........you can embed mplayer within QWidget in window o.s .
Simply use the -vo option with directx:noaccel ........
this is solution..............