Trying to play video/stream Fixing Error in QGraphicsVideoItem [SOLVED]

SGaist

Hi,

Line 10: You didn't give the type of player
Line 14: You didn't declare nor instantiate an object of class QGraphicsView named graphicsView

ion_knight

Like I said SGaist this is from the examples on Qt, as said before on line 10 have tried

VideoPlayer *player = new QMediaPlayer
got
C:\Qt\Qt5.1.0\5.1.0\msvc2010_opengl\examples\multimediawidgets\videographicsitem\main.cpp:50: error: C2440: 'initializing' : cannot convert from 'QMediaPlayer *' to 'VideoPlayer'
No constructor could take the source type, or constructor overload resolution was ambiguous
tried
QMediaPlayer *player =new QMediaPlayer
got
C:\Qt\Qt5.1.0\5.1.0\msvc2010_opengl\examples\multimediawidgets\videographicsitem\main.cpp:53: error: C2819: type 'QMediaPlayer' does not have an overloaded member 'operator ->'

neither worked

also tried
QGraphicsView graphicsView = new QGraphicsView;

All I want to do is test this example but have no idea what is missing does seem pretty rubbish that even the examples that Qt provide don't even compile.

Well found out what the problem was the example under the help section of Qt5.1 isn't correct googled the same page and it has different code tried the code listed on the site instead and it works.

http://qt-project.org/doc/qt-5.0/qtmultimedia/multimediawidgets-videographicsitem.html

However if anyone knows how to fix this code please let me know as the example above is alot easier to understand than the link above where i got the working code (using just a normal video file instead of an rtsp stream of course).

SGaist

@VideoPlayer *player = new QMediaPlayer; << VideoPlayer is a not the same as a QMediaPlayer@

Anyway, just keep the main from the example since you already modified openFile.

Or add a new function to MediaPlayer to open your network media.

Also note that
@
QString fileName = "rtsp://192.168.100.58:8554/stream";
if (!fileName.isEmpty()) {
mediaPlayer.setMedia(QUrl::fromLocalFile(fileName));

    playButton-&gt;setEnabled(true);
}

@

won't work as expected, you are not giving a local file name there

ion_knight

Yea don't really care about the rtsp section until i can get a normal video playing and get the code compiling. So using the default atm

QString fileName = QFileDialog::getOpenFileName(this, tr("Open Movie"),QDir::homePath());

So should line 10 be

QMediaPlayer *player = new QMediaPlayer;?

As already tried that to no luck , (ha but just tried that again found a typing error gotta love it).

So after fixing that this is now my current main.

@#include "videoplayer.h"

#include <QApplication>
#include <QGraphicsView>

int main(int argc, char **argv)
{
QApplication app(argc, argv);
//VideoPlayer player;
//QGraphicsView graphicsView;
QMediaPlayer *player = new QMediaPlayer;

QGraphicsVideoItem *item;
QGraphicsView *graphicsView;
player->setVideoOutput(item);
graphicsView->scene()->addItem(item);
graphicsView->show();

player->setMedia(QUrl("http://example.com/myclip4.ogv"));
player->play();

player->show();

return app.exec();

}@

but gettings these errors.

C:\Qt\Qt5.1.0\5.1.0\msvc2010_opengl\examples\multimediawidgets\videographicsitem\main.cpp:56: error: C2664: 'QGraphicsScene::addItem' : cannot convert parameter 1 from 'QGraphicsVideoItem *' to 'QGraphicsItem *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast

C:\Qt\Qt5.1.0\5.1.0\msvc2010_opengl\examples\multimediawidgets\videographicsitem\main.cpp:62: error: C2039: 'show' : is not a member of 'QMediaPlayer'

Think i understand how to fix the second error by changing player to graphicsView

e.g.

graphicsView->show();

instead of

player->show();

am i correct in thinking that ?

But with the first error not really sure how to proceed, as no idea how you would typecast
'QGraphicsVideoItem *' to 'QGraphicsItem *'

is it something like

addItem(QGraphicsVideoItem(*item);?

If anyone has a link of how to do this type of typecasting that would be great.

ion_knight

Ok broke down my player and think I have the most basic QMediaPlayer possible. The audio of this file plays from the console but the video doesn't the file type is .mov (h.264). Is there something that I am missing ?

main.cpp
@#include <QCoreApplication>
#include <QMediaPlayer>
#include <QFileInfo>

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QMediaPlayer media;
const QString file = "C:/Users/nick/Downloads/big_buck_bunny_1080p_h264.mov";
QUrl url(QFileInfo(file).absoluteFilePath());
media.setMedia(url);
media.play();
return a.exec();
}@

SGaist

You're creating a QCoreApplication, which means no GUI. Create QApplication and you should be good.

ion_knight

Well i think I am getting there (but changing it to a GUI application doesn't seemed to of changed anything) but I'm presuming by pushing the file into a surface now it should play ? (windows error below related to not having a surface set up for the media file ?).

However the linux version just looks like i need to have the correct URI path (or do i need the URI and to push it to a surface ?). How should i be defining a path in linux to a file like "file://home/ion/Downloads/big_buck_bunny.mov"? Cause at the moment all i get is the errors listed below.

Cheers for help so far.

Windows Error:

no videoWindowControl or videoRendererControl, unable to add output node for video data

Linux Errors:

GStreamer; Unable to pause - "/home/ion/Qt_practice/build-test-Desktop_Qt_5_1_0_GCC_64bit-Debug/big_buck_bunny_480p_h264.mov"
GStreamer; Unable to play - "/home/ion/Qt_practice/build-test-Desktop_Qt_5_1_0_GCC_64bit-Debug/big_buck_bunny_480p_h264.mov"
Error: "Invalid URI "/home/ion/Qt_practice/build-test-Desktop_Qt_5_1_0_GCC_64bit-Debug/big_buck_bunny_480p_h264.mov"."

@#include "mainwindow.h"
#include <QApplication>
#include <QMediaPlayer>
#include <QFileInfo>
#include <QDebug>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
QMediaPlayer media;
const QString file = "big_buck_bunny_480p_h264.mov";
QUrl url(QFileInfo(file).absoluteFilePath());
qDebug() << url << endl;
media.setMedia(url);
media.play();
w.show();

return a.exec&#40;&#41;;

}
@

Ha well i think I am getting closer hopefully this should be the last post :P.

SGaist

Do you have the same error using

@QUrl url = QUrl::fromLocalFile(QFileInfo(file).absoluteFilePath());@

?

ion_knight

Lol well that sorted that linux problem feel a bit foolish now (note to self don't watch a video when it's in a foreign language just asking for trouble) . Now both the linux and the Windows version are doing the exact same only difference is the error output.

Both playing audio but no video. Do i need a Abstract Video surface or ?
Linux:

OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x1b800a0

OpenGL Warning: Retry with 0x8002 returned 0 visuals

OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x1b800a0

OpenGL Warning: Retry with 0x8002 returned 0 visuals

OpenGL Warning: glXGetFBConfigAttrib for 0x1b800a0, failed to get XVisualInfo

over and over

Windows:

no videoWindowControl or videoRendererControl, unable to add output node for video data

but yea still get the same error on the windows side. Also just so your aware running the linux machine in a VM.

SGaist

A QVideoWidget should do it

ion_knight

Ha yea What i ended up using in the end below is the updated code using QGraphicsView or QVideoWidget. Ha now all i need to do is figure out how to apply this to an RTSP stream but thats for another day :D. Cheers SGaist been very helpful.

@#include "mainwindow.h"
#include <QApplication>
#include <QMediaPlayer>
#include <QFileInfo>
#include <QDebug>
#include <QVideoWidget>
#include <QGraphicsView>
#include <QGraphicsVideoItem>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;

QMediaPlayer *player = new QMediaPlayer;
 player->setMedia(QUrl::fromLocalFile&#40;"C:/Users/nick/Downloads/big_buck_bunny_1080p_h264.mov"&#41;&#41;;
 QVideoWidget *videoWidget = new QVideoWidget;
 w.setCentralWidget(videoWidget&#41;; // if w is a QMainWindow
 player->setVideoOutput(videoWidget);
 player->play();

/*
QGraphicsView *graphicsView = new QGraphicsView;
w.setCentralWidget(graphicsView); // w = QMainWindow
QGraphicsScene *scene = new QGraphicsScene;
QMediaPlayer *player = new QMediaPlayer;
QGraphicsVideoItem *item = new QGraphicsVideoItem;

graphicsView->setScene(scene);
player->setVideoOutput(item);

graphicsView->scene()->addItem(item);
//player->setMedia(QUrl::fromLocalFile&#40;"C:/Users/nick/Downloads/big_buck_bunny_1080p_h264.mov"&#41;&#41;;
player->setMedia(QUrl("rtsp://localhost:8554/stream"&#41;);
player->play();*/

w.show();

return a.exec(&#41;;

}@

Btw when should I be using either? because currently just tempted to do all video output using videowidget as it looks the simpliest, is there any situation when i should use Graphics View or QAbstractVideoSurface over VideoWidget?

SGaist

For your tests, you should keep using the QVideoWidget. Once you have everything working, you can start playing with QGraphicsView and friends

ion_knight

Doesn't really answer my question but ah well setting it to solved.

SGaist

Did you meant: In which case should I use QVideoWidget and in which one QGraphicsView ?

ion_knight

Yea can't seemed to find a good example of their usage. Also would you know why QVideoWidget doesn't work on linux with that code but graphicsview does?

@#include "mainwindow.h"
#include <QApplication>
#include <QMediaPlayer>
#include <QFileInfo>
#include <QDebug>
#include <QVideoWidget>
#include <QGraphicsView>
#include <QGraphicsVideoItem>

int main(int argc, char argv[])
{
QApplication a(argc, argv);
MainWindow w;
/ QMediaPlayer *player = new QMediaPlayer;
const QString file = "big_buck_bunny_480p_h264.mov";
QUrl url = QUrl::fromLocalFile(QFileInfo(file).absoluteFilePath());
player->setMedia(url);
QVideoWidget videoWidget = new QVideoWidget;
w.setCentralWidget(videoWidget); // if w is a QMainWindow
player->setVideoOutput(videoWidget);
player->play();/

 QGraphicsView *graphicsView = new QGraphicsView;
 w.setCentralWidget(graphicsView); // w = QMainWindow
 QGraphicsScene *scene       = new QGraphicsScene;
 QMediaPlayer *player        = new QMediaPlayer;
 QGraphicsVideoItem *item    = new QGraphicsVideoItem;

 graphicsView->setScene(scene);
 player->setVideoOutput(item);
 const QString file = "big_buck_bunny_480p_h264.mov";
 QUrl url = QUrl::fromLocalFile&#40;QFileInfo(file&#41;.absoluteFilePath(&#41;&#41;;
 graphicsView->scene(&#41;->addItem(item);
 player->setMedia(url);
 //player->setMedia(QUrl("rtsp://localhost:8554/stream"));
 player->play();
      qDebug() << url << endl;
w.show();
return a.exec&#40;&#41;;

}
@

The weird thing is linux says that it "Failed to start video surface" yet the video still plays bit random (but crashes after a while sometimes). (mind you probably a good idea to just create a new post to answer this question).

SGaist

The only good answer is: it really depends on the application you are writing (I know might not sound helpful) If you are not doing anything special that would require a QGraphicsView then go for the widget.

As for your last question, you could directly try to see the "bug report system":http://bugreports.qt-project.org/issues and check whether it's a known issue