Only perform source filter discovery once on connect

[GoogleCodeExporter]

Describe the issue you're having:
Some source filters (MS WM ASF Reader) send a new media type on every seek, and 
the extra effort trying to re-init the whole decoder can make it slower, and 
even cause deadlocks in some bad situations (because of the filter graph 
probing and a filter graph lock the WM ASF Reader seems to hold)

How can the issue be reproduced? Sample File?
Have to figure this out..

Implementation Notes:
A lot of the information needed when creating the decoder can be obtained once 
when a connection is established to the source filter, and doesn't need to be 
probed again later, because the filter graph doesn't change.

Original issue reported on code.google.com by h.lepp...@gmail.com on 21 Feb 2013 at 7:03

[GoogleCodeExporter]

This problem has been mostly solved by re-structuring the reconnection logic of 
the input pins.

Original comment by h.lepp...@gmail.com on 14 Dec 2014 at 10:44

• Changed state: Done