def _pad_added(self, element, pad):
        """The callback for GstElement's "pad-added" signal.
        """
        # Decoded data is ready. Connect up the decoder, finally.
        name = pad.query_caps(None).to_string()
        if name.startswith('audio/x-raw'):
            nextpad = self.conv.get_static_pad('sink')
            if not nextpad.is_linked():
                self._got_a_pad = True
                pad.link(nextpad)