There was a known memory leak problem with older versions of the MPC-HC decoder (before rev 1024) - the SAF filter pack uses rev 1043 (because Hoborg thinks this is the best version so far).
I use build 1043 but will check without DXVA tonight to see if that changes anything. It doesn't really bother me, but I guess it could be a memory hog having 25 instances of Haali running...
I tested using ffdshow and coreAVC last night, but the problem persisted as long as I had Haali installed, DXVA or no DXVA. I can stop it from happening by enabling the Internal Matroska filter in MPC HC, AND blocking these External Filters:
Haali Media Splitter
Haali Matroska Muxer
Haali Media Splitter
I briefly see the Haali icon but it goes away again, and Graphstudio tells me that I'm using the Matroska filter. Uninstalling Haali gives really bad and choppy video.
The jungle of filters is hard to find the real path in