After doing more reading on various Internet forums, it seems that HDMI pass through of 5.1 bitsteam audio to optical (or sometimes coax) output by TVs is a hit or miss proposition - some do it and some do not, even for current models. And those that do it sometimes only do Dolby Digital and not DTS. Those that do pass DTS also sometimes have a very long delay in the audio. In addition, some that do pass through 5.1 only do so if you only do pass through. If your try to have the TV decode the signal and play the sound, some will not also pass through the 5.1 signal. That means you will need to change the TV speaker setting if you want to use the TV speaker for sound. Also, some TVs only allow pass through on one of the HDMI inputs.
I have read that the HDMI HDCP standard does not strictly allow such pass through from HDMI inputs but some manufactures do it anyway. None HDMI signals (Netflix for example) are not restricted, but signals received through HDMI are. Some manufactures seem to simply ignore the EDID settings and pass it through anyway. It some cases people go into the service menus and set an option to allow pass through. I guess that gets the manufacturer from getting in trouble with the HDCP rules. I do not know all the details but I found this discussed several places.
Some of the reported problems with TV not doing 5.1 pass through may be user error. But enough have problems even with new models to make me believe this can be a problem depending on manufacturer and even model.
From what I read, you need to be careful if you want to do 5.1 pass through of an HDMI signal through a TV. It is not uniformed implemented, even on new models. If it works fine, otherwise you can go directly from the source to your receiver with the bitstream.
