Sets the state of the element. This function will try to set the
requested state by going through all the intermediary states and calling
the class's state change function for each.
This function can return GST_STATE_CHANGE_ASYNC, in which case the
element will perform the remainder of the state change asynchronously in
another thread.
An application can use gst_element_get_state() to wait for the completion
of the state change or it can wait for a GST_MESSAGE_ASYNC_DONE or
GST_MESSAGE_STATE_CHANGED on the bus.
State changes to GST_STATE_READY or GST_STATE_NULL never return
GST_STATE_CHANGE_ASYNC.
Sets the state of the element. This function will try to set the requested state by going through all the intermediary states and calling the class's state change function for each. This function can return GST_STATE_CHANGE_ASYNC, in which case the element will perform the remainder of the state change asynchronously in another thread. An application can use gst_element_get_state() to wait for the completion of the state change or it can wait for a GST_MESSAGE_ASYNC_DONE or GST_MESSAGE_STATE_CHANGED on the bus. State changes to GST_STATE_READY or GST_STATE_NULL never return GST_STATE_CHANGE_ASYNC.