If BS.Player's accompanying program "codecmanager.exe" finds some of its preferred codecs/filters are already installed on your system, it will not also install them locally as BS.Player will then use the system's filters/codecs.
If you want to know which filters/codecs BS.Player is actually using for playback of any specific file, just load that file and then look under
(rightclick >) Options > Filters > Advanced
There you will be able to find the codecs/filters which are actually used by BS.Player for that specific file.
When you click on the small [+]-signs in front of the filters/codecs shown, further information (and access) to those filters becomes accessible.
(Note: do not forget to also click on "source", as that may reveal usefull info too).
Note: codecmanager.exe and BS.Player's "Filter management" (under rightclick > Options > Preferences > Filter management) are two separate things. The first is an auxiliary program to check if BS.Player's preferred codecs/filters are installed and up-to-date (
and if not installed it will install 'internally' if permitted by you and/or if not up-to-date it will show you). The second one is BS.Player's in-built filtermanager, allowing you to e.g. change filter-priority or to blacklist certain (system's) filters for use by BS.Player (e.g. if that filter causes problems).
When a filter is blacklisted by you in BS.Player's Filter management, BS.Player will - as a rule - automatically search and find another (combination) of splitter/filters/codecs to play the file.