The sink will emit this signal as soon as it has gathered enough information from the video to configure a pipeline.
If the application wants to do some customized rendering, it can setup its pipeline after this signal is emitted. The application's
pipeline will typically either be a copy of the one returned by clutter_gst_video_sink_get_pipeline or it can be a completely
custom pipeline which is setup using clutter_gst_video_sink_setup_pipeline.
Note that it is an error to call either of those functions before this signal is emitted. The new_frame signal will only be emitted after the pipeline is ready so the application could also create its pipeline in the handler for that.