'Configure the supplied source for use.
Should be called whenever we get a new appsrc.'

def configure(self, source):

    source.set_property(u'caps', self._caps)
    source.set_property(u'format', 'time')
    source.set_property(u'stream-type', 'seekable')
    source.set_property(u'max-bytes', (1 << 20))
    source.set_property(u'min-percent', 50)
    if self._need_data_callback:
        self._signals.connect(source, u'need-data', self._on_signal, self._need_data_callback)
    if self._seek_data_callback:
        self._signals.connect(source, u'seek-data', self._on_signal, self._seek_data_callback)
    if self._enough_data_callback:
        self._signals.connect(source, u'enough-data', self._on_signal, None, self._enough_data_callback)
    self._source = source
