How to disable some DirectShow filters loading in DO only (not all system)? I tried to add their IDs to ignore_context_menus, but it did not help.
There's no way to do that unless the filters themselves provide a way (some do).
Note that on a 64-bit OS, Opus uses 64-bit components, while most video playback tools are 32-bit, so uninstalling or unregistering the 64-bit DLLs may work, unless you need them in other 64-bit apps.
(Some viewer plugins will still use 32-bit DLLs, though. Specifically ones which are used via the ActiveX plugin. Not the Movie plugin, though.)
Since I do not fully understand the question or Dopus, this response may be a non-sequitur.
Drac144
In thumbnails mode or when cursor is over the video file, DOpus loads available DS filters. All installed filters are working, but DOpus 11 very often terminates with error (0xC0000005, dopus_function etc.). I don't need to turn off filters in the whole system, I just wanted to DOpus doesn't load only the specified DS filters.
Installing more stable filters is another option. The FFDShow and MediaPlayerClassic-HomeCinema codec and filters have done me well over the years, although these days I don't seem to need to install them anymore as most video is in formats Windows can play out of the box.
There's a guide in the FAQs section with recommendations.
Yes, today I deleted jetaudio, all other DS filters, and install mpc-hc with lav filters. Maybe it will work stably.