Using DigiESP, make a new kernel and rootfs with apps project, then hit the configure button. Do a search for gstremer, it should appear under rootfs config, pre-built apps. And is selected by default.
If you need info on gstreamer,
Check in the help section of the DigiESP gui, under the Built in Applications and services you can find section 7.6.20 Gstreamer, more info can be found at http://gstreamer.freedesktop.org/
The Qt backend on Linux uses GStreamer you should have libgstreamer0.10_0.10 as the minimum with also plugins.