I have a Denon 4300 connected to a Trek tuner TUNVR1 connected by HDMI. The tuner says it is putting out Dolby digital. The input on the Denon is set for an HDMI only input (no other audio source is listed as connected). The on screen info from the Denon shows the input info pcm stereo. How do I get the Denon to detect the audio input from the trek as Dolby digital.