I asked this one on the IRC channel, but did not get an answer and so I am re-asking the question here:

"I have changed the rate of the pipeline by calling gst_element_seek (apPipeline, 2.0, GST_FORMAT_TIME, GST_SEEK_FLAG_NONE, GST_SEEK_TYPE_NONE, GST_CLOCK_TIME_NONE, GST_SEEK_TYPE_NONE, GST_CLOCK_TIME_NONE); so that the pipeline runs twice and fast.  With this said, I was wondering whose responsibility should it be in the pipeline to send a new segment with the rate update if no actual seek was performed?"

It is my understanding that the element performing the seek (e.g. qtdemux) should send the new segment, but in this case there's no actual seek being performed - just a rate change.  Hence, my question.