If you don't use CoreCCParser, you can keep to '0'
Or any other "random" DS filter that might inject itself inbetween ffdshow video decoder and TsReader. It would be possible to traverse all the filters from TsReader video output pin to EVR/VMR video input pin and remove the registry hack. I would say it would be worth as it would save the error reports we are getting because of the broken ffdshow.
...ffdshow really should fix up their broken timestamp handling