intervideosrc/intervideosink: cannot change channel while in playing state

Submitted by lou..@..il.com

Link to original bug (#722877)

Description

Once the intervideosrc and intervideosink elements are in the playing state, changing the channel property does not have any effect on their behavior. The elements must be moved to null and then back to playing for the channel behavior to change.

Version: 1.2.0