The issue of HDTV passing more than stereo when the source is HDMI is well done. CNET noted this long ago at https://www.cnet.com/news/20-tvs-tested-which-sets-can-pass-surround-sound-to-a-sound-bar/
My thought is Sony does because they own a lot of patents and because who would challenge them. The others may just flaunt the rules or other reasons.
So nope, you can't count on passing audio on a HDTV.
I recently upgraded to an LG 60UH770 smart tv. I also upgraded the set-top box to an Arris VIP5662W 4K DVR to get Bell Aliant 4K video. My issue is with the optical audio out setting and the audio signals produced. I have been informed that I cannot pass a 4K hdmi signal though my recever (Sherwood Newcastle R772). Nor is it HDMI RAC capable. Therefore the HDMI goes from the set-top box to the TV and an optical toslink cable goes from the TV to the reciever.
TV Sound out set to Dolby Digital bitsream and it sounds great. Except when I change channels or use the smart TV for wireless sreaming of netflix and youtube.
The surround mode on the receiver is set to automatic. It is constantly switching whenever a channel is changed and sometimes fails to decode when a new audio signal is viewed. the resulting (uncoded ) sound is terrible sending the kids running and me to the receiver to switch the surround to the next setting.
The problem is corrected when I change the TV output to PCM but the surround sound sucks. who wants that!
I switched the receiver surround to manual and set it a DD Pro ogic IIx. the constant switching is gone and things work fine with the 4k set-top but the issue returns when I use the smart tv for netflix and youtube. Its kind of a pain.
It seems that the receiver can decode all the signals buts gets messed up when the signal is changed to another format.
Any ideas, comments or suggestions?