Qt5 multimedia - mjpeg support

vwinnie

Hi all,

i'm trying to capture mjpeg stream arriving from a ip camera and display the "video" using QMediaPlayer and QVideoWidget.
The code is very basic:
@
mediaPlayer = new QMediaPlayer;
connect(mediaPlayer, SIGNAL(mediaStatusChanged(QMediaPlayer::MediaStatus)), this, SLOT(currentMediaStatus(QMediaPlayer::MediaStatus)));
mediaPlayer->setMedia(QUrl("http://security.camera.local/mjpg/video.mjpg"));
mediaPlayer->setVideoOutput(videoWidget);
videoWidget->show();
mediaPlayer->play();
@

Unfortunately the one and only status i can receive is QMediaPlayer::LoadingMedia with QMediaPlayer::StoppedState .
The videoWidget doesn't display anything.

Does QMediaPlayer support mjpeg at all?
Although i do not receive neither QMediaPlayer::InvalidMedia status nor any other error.
Of course i could use QDesktopServices to display the stream with a web browser but i'd prefer using my own video widget...

Env: Qt5.0.1 mingw47, Windows7 x64

Thanks:
Rudolf

noah.k

Hello,

I am facing the same problem but I get an error when loading the ip camera stream http://../mjpeg.cgi
-->"Error: Failed to load source."

You need to add an error handler in your code in order to get this error message:
connect(mediaPlayer, SIGNAL(error(QMediaPlayer::Error)), this, SLOT(handleError()));

In handleError method you can get the error message by this call -> mediaPlayer->errorString()

You said:
"Of course i could use QDesktopServices to display the stream with a web browser but i’d prefer using my own video widget…"
Could you be more explicit about this solution, please ? I am really interested.

Thanks.

Noah

noah.k

You need to add an error handler in your code in order to get this error message:
@connect(mediaPlayer, SIGNAL(error(QMediaPlayer::Error)), this, SLOT(handleError()));@

vwinnie

Hi Noah,

thanks for your reply!
QMediaPlayer has a static member hasSupport. I called it with the appropriate mime type (video/x-motion-jpeg) to determine whether it is supported or not.
The function returned the QMultimedia::MaybeSupported enum which is quite funny...

I'll check the error signal tomorrow.

QDesktopServices offers methods for accessing common desktop services on different desktop environments.
The static bool QDesktopServices::openUrl(const QUrl& url) method will open your http://../mjpeg.cgi with your default web browser.

Rudolf

noah.k

Hi Rudolf,

Take a look at "this":http://code.google.com/p/qimagegrabber/ project.

vwinnie

Appears promising...

Unfortunately now i have to go one step further. The app must support rtsp streams as well so i try to use "vlc-qt":http://qt-apps.org/content/show.php?content=133649 now