So I've been working on trying to improve media playback on my Sony the past couple days, and made a couple interesting discoveries.
First, 3D. As I said above, for 3D YouTube, you have to run Smart YouTube TV (a custom app that is pretty slow) in Pro mode forcing AVC codec (instead of VP9) OR (do something we won't talk about) and play the videos locally.
Now, I'm still digging into this, but it IS possible to have 3D videos outside of Sony's app if there is a 3D flag. I have some 3D that will play under Kodi and others that won't. I will find out why if it kills me.
Second, I found a great fix if you are using a multi channel sound system.
Under Kodi, which I'm hoping most of you are using:
First make sure you didn't enable 'Sync Playback to Display' that option disables audio passthrough.
Go to System/Settings/System/Audio.
Change the 'Number of Channels' to 2.0. I know this doesn't make sense, just do it.
Farther down the page, check 'Allow Passthrough'.
Then select, Dolby Digital (AC3) capable receiver.
Finally, the most important part, which only appeared BECAUSE you set the number of channels to 2: select 'Enable Dolby Digital (AC3) transcoding'.
Kodi has the least well named settings I've ever seen.
Now, all those DTS, DTS-HD MA, TrueHD, and AAC multi channel tracks will get re-encoded to multichannel DD and passed through to your sound system. No more stereo playback.
Sony's App is garbage at transcoding AAC. It creates warbley garbage. Kodi does a brilliant job.
The only downside is that Sony's App will passthrough DTS and the core of DTS-HD MA. Kodi always re-encodes. SUPPOSEDLY, there is a way to enable DTS Passthrough, but I can't make the option appear.
I'll keep you all posted when I figure out how to get 3D to play on Kodi...
Edit: Okay, so it turns out Sony uses a private API in the Nougat Android TVs, and the official DTS API under Oreo. While the Sony app can stream DTS tracks, no one else can.
So either we need a hacked firmware based on the newer TVs', or get an add-on smart device.