how to get Cuda to work on conversations?

Hi guys, im no programer nor dev. I am simply a home user who convert video files for iwn usage.
So i use an app called WinAvi aio Converter, i have a gtx 980Ti.
If Cuda is Enabled in WinAvi, then converting a 1.5gb mkv file to Mp4 would usualy be done within 8-12 min.
These days, non of the converting siftwares out there, can find the Cuda Engine to work with, its like thers no Cuda.
This is resulting with conversation of 30-45min INSTEAD 8-12min.
Please guys i need this to work.
Im sorry if i dident use the right words of you dev’ and programers. Im no pro, all i know its called cuda, and without it my life is a mess.
Help please.
Thank you