[gst-devel] Using Qt screen output from a gstreamer plugin

Wolfson, Alexander alexander.wolfson at intel.com
Thu Jun 22 17:21:26 CEST 2006

Hi all,

Using Qt screen output from a gstreamer plugin was probably discussed
before, but I was not able to find a small example.
There are planty of big KDE projects that use gstreamer, but I am afraid
that it will take forever to understand what is going on there.

We have a Qtopia application which calls a gstreamer application to play
video on XScale powered device.
The only problem is the last sink. Because the original App that owns
the screen is Qtopia app I thought that it is a good idea to write a Qt
based image sink for gstreamer. I wrote it using a generating from
template mechanism. Unfortunately the only template available was for
filter so I tried to convert the generated code to sink plugin.

I have 

extern "C" void gstQtShowBuffer( unsigned char * buf, unsigned int
function inside of my Qt programm.

inside of gst_qtimagesink_chain() in my plugin I put
gstQtShowBuffer(GST_BUFFER_DATA(buf), GST_BUFFER_SIZE(buf))

now when I look at 

>GST_DEBUG="*:3" gst-inspect
 shows that gstQtShowBuffer symbol is not found

So I guess I have to split my Qt application into main part and .so
.so part will have only gstQtShowBuffer related code.

I am anticipated a lot of problems, because I don't have experience
neither with Qt nor with gstreamer.

I am pretty sure that people already did it thousands time before, but
was not able to find a small example.

Could somebody show me an existing example of writing to Qt screen from
gstreamer plugin?
It is probably a part of more general issue of mixing gstreamer and Qt

Thanks a lot in advance,


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