Legacy 5.1 DTS at 1509 kbps can be transported by optical Toslink and most AVR's can decode that ( > 7 year old Sony AVR's are reported to have problems though ).
But nowadays buying a new HDMI 1.3 AVR that can decode the new advanced audio codecs in 7.1 (lossy DTS-HD HR & lossless DTS-HD MA). is the way to go if you can buy a new AVR. Unfortunately the PS3 is reported to not have the right HDMI 1.3 transmitter chip that can bitstream the raw advanced audio codecs out (at least Sony has not offered that capability on the PS3 yet). Other Blu-ray players can do so however.
But nowadays buying a new HDMI 1.3 AVR that can decode the new advanced audio codecs in 7.1 (lossy DTS-HD HR & lossless DTS-HD MA). is the way to go if you can buy a new AVR. Unfortunately the PS3 is reported to not have the right HDMI 1.3 transmitter chip that can bitstream the raw advanced audio codecs out (at least Sony has not offered that capability on the PS3 yet). Other Blu-ray players can do so however.