I'm having trouble with surround sound when playing BluRay discs on PS3. The PS3 connects to my surround sound receiver using optical cable. I know it only happens with BluRay discs because I can play video (.AVI) that has 5.1 surround sound via PS3 (my receiver displays all the channels it's got signals from). But, when playing BluRay discs, the sound is only stereo (2 channels). I think it only happened rather recently, but I hadn't watched Bluray movies for a while. My system hasn't been updated for more than a year, but I don't think this is really the problem as (again I think) it worked fine before.
Please let me know what is wrong with BluRay playback, how I can fix it, and if it's a setting that I overlooked. I think it's a setting mix-up, but I tried and failed to make it works.
Thank you,
T