[Interest] QtQuick and Video

Robert Voinea rvoinea at gmail.com
Mon Nov 5 12:54:57 CET 2012


Has anyone tried the QtQuick 1.0/1.1 and Video combination?

I have to implement a simple interface for several video streaming sources in 
QML (one video "window" and several buttons that change the video source) and 
I don't seem to get it right.

I am using ubuntu 12.10.

QtMultimediaKit is installed, and phonon-backend-vlc... and phonon-backend-
gstreamer. In system settings I have set vlc as the preffered phonon 
backend... But it get this on the console when I try to load a simple video 
(captured with VLC from my laptop's webcam):
	(test:11708): GStreamer-CRITICAL **: gst_object_ref: assertion `object != 
NULL' failed
	(test:11708): GStreamer-CRITICAL **: gst_object_ref: assertion `object != 
NULL' failed
	(test:11708): GStreamer-CRITICAL **: gst_element_set_state: assertion 
`GST_IS_ELEMENT (element)' failed
Apparently phonon ignores the vlc backend and always uses gstreamer.
(any ideea how can I force phonon to use the vlc backend instead of 
At this point I don't use streams... but a single file (OGG/Theora).
This is my test file: 

import Qt 4.7
import QtMultimediaKit 1.1
	id: rootWindow
	width: 1024
	height: 768
		id: video
		width: 640
		height: 480
			centerIn: parent
		fillMode: Video.PreserveAspectFit
		source: 'test.ogv'

I have tried with both gstreamer and vlc backends. I don't care which one I 
have to use as long as I can set the source as an URL... 

At the moment I am considering writing my own QML element that displays a 
video stream using (probably) the native vlc API... or something like this:

Thank you in advance! :)

Robert Voinea
Software Engineer
+4 0740 467 262

Don't take life too seriously. You'll never get out of it alive.
(Elbert Hubbard)

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