MakeMKV comes with two versions of ffmpeg. Look in the MakeMKV folder and you'll see them as mmffmpeg.exe and mmffmpeg64.exe. Use the appropriate one for your version of Windows.
You'll also need a DTS decoder from Arcsoft TMT 5 or PowerDVD. The one I used from TMT 5 is named dtsdecoderdll.dll. There is a trial available for TMT5 that you can download.
You'll need to open the Advanced tab in Preferences to apply these of course.