Confused. TV is 4K. If I set the Ultra to Display Type->4k (no matter the refresh rate or HDR) or AutoDetect, the resulting picture looks 'soft'. If I set the Display Type to 1080p, the picture is crisp. The input stream is not 4k (ATT TV Now). Does the Roku do anything to the output stream depending on the Display Type setting? Since the input is (mostly) 1080p, the output should be the same, and the TV will do the upscaling, right? Or does the Rokup upscale if the the Display Type is set to 4K.
I've been an electronics technician and an app developer for 40+ years, but I can't get my head around this.
Oops. Forgot to add that all HDMI video is processed through a AVR. Only one HDMI cable goes to the TV.
The Roku does all the upscaling to the resolution configured (and your TV may do additional upscaling to its native resolution)
E.g.: Roku is configured to 1080 (upscales everything to 1080p) connected to a 4K TV (most likely upscales the 1080p to 4K)
E.g.: Roku is configured to 2160p (4k - upscales everything to 2160) connected to a 4K TV (no upscaling, at native resolution)
I should add that configuring your Roku to 1080p will limit apps to 1080p internally (by and large), so if you want to manually configure the Roku to 1080 to watch lower resolution content (so your TV upscales it), you'll want/need to configure it back to 4K to watch 4K content.
This makes sense in that when set to 1080p, it's up to the TV to upscale the image -- which it appears to do better than the Roku does when it is set to a 4K display type. To sum up, when the Roku is set to 1080p mode, all output is 1080p and the 4K TV upscales. If I want to watch a true 4K video, I'll have to set the display type accordingly.