gstreamer configuration

[prkhr4u]

I want to run gstreamer APIs in QT.
I have successfully installed gstreamer sdk and am able to run its tutorial using gcc.
I have configured the QT and set all the environment variables in QT project settings.
My pro file is as follows:

QT       += core gui
 
TARGET = streaming
TEMPLATE = app
 
 
SOURCES += main.cpp\
        mainwindow.cpp
 
HEADERS  += mainwindow.h
 
FORMS    += mainwindow.ui
 
unix {
    CONFIG += link_pkgconfig
    PKGCONFIG += gstreamer-0.10
}

QT       += core gui

TARGET = streaming
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp

HEADERS  += mainwindow.h

FORMS    += mainwindow.ui

unix {
    CONFIG += link_pkgconfig
    PKGCONFIG += gstreamer-0.10
}

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However when i build,it is giving an error like:

Project ERROR: Package gstreamer-0.10 not found

Project ERROR: Package gstreamer-0.10 not found

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I guess I am missing some configuration settings.
Pl help
P.S.: using ubuntu 12.04