gistfile1.py

#!/usr/bin/env python

# See https://github.com/Elleo/gst-opencv/blob/master/examples/python/facedetect.py
# See also http://blog.mikeasoft.com/2010/06/17/gstreamer-opencv-plugins-on-the-nokia-n900/

import pygst
pygst.require("0.10")
import gst
import gtk

class FaceDetect:

    def __init__(self):
        pipe = """autovideosrc ! decodebin ! ffmpegcolorspace ! facedetect profile=/usr/share/OpenCV/haarcascades/haarcascade_frontalface_default.xml ! fakesink"""
        self.pipeline = gst.parse_launch(pipe)

        self.bus = self.pipeline.get_bus()
        self.bus.add_signal_watch()
        self.bus.connect("message::element", self.bus_message)

        self.pipeline.set_state(gst.STATE_PLAYING)

    def bus_message(self, bus, message):
        st = message.structure
        if st.get_name() == "face":
            print "Face found at %d,%d with dimensions %dx%d" % (st["x"], st["y"], st["width"], st["height"])

if __name__ == "__main__":
    f = FaceDetect()
    gtk.main()