I'm trying to get the Firefox Extension "Video Download Helper" (VDH) to convert and record videos. The suggested way of doing this is to install a precompiled version of libav called "Convert Helper" from the VDH Homepage.
I'm not willing to do that for various reasons.¹
So I want to install libav on my Windows 7 (x64) system and point the addon to the right .exe/.dll/whatever it needs. There is an option to enter a "converter path" manually in the settings, although it does not work for me - probably because I'm not entering the correct path. The entered path just disappears after I click on the "Recheck converter" button. (I'm not really sure if the corresponding field is even made for input. You can see a picture of the settings page here in the "Using conversion rules" section.)
The question is: How do I install libav correctly?
libav provides Windows builds in the download section, but I don't know where to put the extracted files or how to make the Firefox addon recognize the installation. Do I just throw the .dlls and .exes in the System32 folder or probably somewhere in the system's $PATH variable? Is there any other way?
Any ideas are much appreciated.
¹One of them is that they want me to pay for a completely free codec to avoid watermarks which is (a part of) why they appear on libav's Hall of Shame (remark (3/29/2016): the Hall of Shame is removed until further notice). On Linux there's no problem whatsoever (see installation instructions for Linux). Another reason is the fact that I want to have some level of control about what's installed on my system and that "ConverterHelper.exe" obviously is not just a compiled version of the libav codec.