First of all the DVD has to be a dts DVD and this is NOT determined by the credits. The credits just mean that at some point (probably when the movie was in the theater) it was available in dts. The DVD will say dts in a red box somewhere either on the front or back, also you can go to www.dtsonline.com to check all the DVDsavailable in dts. Second, assuming the DVD is recorded in dts, you need to select dts from the dvd menu. Sometimes this is hidden somewhere and you might need to look for it. It may be in an "audio" section, may be in the "extras" section, but most likely it's in the "languages" section. You would select "English dts" and play the movie and your source should switch to dts.