for npapi put it in your plugins directory, like for pale moon: C:\Program Files\Pale Moon\browser\plugins
for activex do: regsvr32 bink2ax.ocx
if activex complains install cert.pfx in Trusted Root Certification Authorities, password is 123
if explorer complains, make sure it launches in 64 bit mode by HKEY_CURRENT_USER\SOFTWARE\Microsoft\Internet Explorer\Main and setting the DWORD TabProcGrowth to 0

Q: Why does this exist?
A: Summer break.

Q: Does this actually work?  
A: Works on my machine.

Q: Can you add a volume slider, a progress bar, or fullscreen?  
A: Make me.

Q: What's the use case for this?  
A: This is an exercise for the reader.

Q: I have more questions than answers.
A: maksw@maksw.pl

Q: Can I use this in production?
A: ...