This page should guide the developer to a build environment.
If kdenlive crashes on startup (e.g. in QtCreator) and shows a message like:
kdenlive(24309) KXMLGUIClient::setXMLFile: cannot find .rc file "kdenliveui.rc" for component "kdenlive"
then you have to ensure the .rc file is found. If CMake is configured to install Kdenlive to /usr/local, the .rc file is put there, but when kdenlive is then run from the build directory, the KXMLGUIClient will not search there. Solution: Set the environment variable KDEDIRS to $KDEDIRS:/usr/local.
You can get more information about the paths that are checked by running kdenlive like this:
strace build/src/kdenlive 2>&1 | grep kdenliveui.rc