DTS-HD

Need help understanding DTS Master Audio. I have a Samsung BD-F5900 Blu-ray player attached to a Yamaha RX-V475 via HDMI. I have the audio on the Blu-ray player set to output unprocessed bitstream but when I play a movie, the receiver only displays DTS and not DTS MA. Is this because the receiver is only 5.1 channel and am I really getting the full lossless audio provided by DTS MA? Aside from the extra channel audio, should I set the player to output PCM and will I be getting higher audio by setting it to PCM?

- K. Mastrogiovanni
Galt, CA