Nikolay Sivov (@nsivov) commented about dlls/mf/session.c:
switch (event_type) { case MESourceSeeked:
seeking = TRUE; case MESourceStarted:
I'd like to suggest a cosmetic change here - set "seeking" once, before event type switch as "event_type == .. || event_type == ..", that would be easier to follow.
Also, commit message says the opposite to what this change is doing - if MFT_MESSAGE_NOTIFY_START_OF_STREAM could be called starting or restarting a transform, you're skipping it now when seeking.