I sent you an email. You must first get the dll file by buying Arcsoft TMT, for example.
Then:
Just put this into one of the folders. I'd recommend the system folders (check whether you have a 32 bit or 64 bit version of Windows). That's it. May be advisable to restart your PC if it doesn't work in decoding immediately.
Also, note that the dll file is not required if you want your receiver to do the decoding. Of course, you need a receiver that has HDMI and can handle this. This option is called Bitstreaming, and can be set in options>video>Bitstreaming.