Wrote this kind of addressing somebody at Roku, not the general community.
Bit-Perfect or Hi-Res audio seems like a really simple thing to support in 2020, especially since over HDMI, you should be using the DAC of whatever the Roku is plugged into. Not only that but with support for 4K and HDR, I think the Roku should be more than powerful enough to support bit-perfect audio. And yet, whether I'm using Plex (where I have several 24b/192kHz files hosted, Tidal, Amazon, DLNA/UPnP, my receiver reports that it's streaming Linear PCM @ 48kHz. Isn't it past time you supported Bit-Perfect audio so people wouldn't have to have multiple streaming boxes and switch inputs for music services that you have to control with either phone/tablet or tiny touch screens, generally with limited or poor user experiences? The Chromecast Audio supported it, and I believe the regular Chromecast does as well. Aren't all your devices more powerful than those?
Also, isn't it a bit disingenuous to advertise the Roku Smart Soundbar as "premium" sound? I mean, I personally have the Roku Ultra (4670 series) , but if I WERE considering buying one, I'd be pretty annoyed to find out it didn't support higher resolution audio when your own website advertises "premium" and "studio-quality" sound (which is a complete joke), or maybe not because anybody buying something like that probably doesn't care about music quality anyways, and probably doesn't know the difference. If those terms were technical, you'd probably get sued for false advertising.
Then again, maybe that's just the audience you're targeting... The ones who don't know any better. Sad.
My Ultra 2020 can play flac 24 bit 192 kHz and decompress the lossless audio to PCM, like all devices that decodes flac. It will send the audio to my receiver at the same sampling rate of the file, in this case 192 kHz.
In Roku's settings I have audio set to passthrough. It has the latest firmware 9.4.2 4182-C2 and the latest Roku Media Player, which is what I use on the Roku (for now). The only other settings that I can see that has anything to do with sending info over HDMI is the display refresh rate, which I have set to auto adjust refresh rate. Its not associated with audio at all, but one can never tell with firmware and HDMI compatibility.
BTW, I tested it again, using USB drive connected directly to Ultra and streaming DLNA, and in both cases I still received 192 kHz on a file I created from a 96 kHz Dolby TrueHD source and resampled to 192.
I bought the 2020, the passthrough option is only available there. I'm still considering returning it though and getting a different steamer because now apparently the new remotes won't control audio for a receiver?