I recently bought a UBP-X800 blu-ray player. It is connected to my Samsung 4K TV through a HDMI cable and my TV is connected to 5.1 channel sound system through an Optical cable. I am able to stream movies and other internet content from my TV and a Roku connected to my TV in 5.1 surround sound. But the videos played in Sony player is only 2.1 channel sound. Not able to hear any sounds from the rear speakers. Any help to resolve this is appreciated.