Display MoreThanks noggin it looks like the issue is with my receiver. The newer builds work fine if I plug my pi4 directly into the tv.
Here's an example which exhibits the issue
https://4kmedia.org/samsung-wonderland-two-hdr-uhd-4k-demo/
My bravia has android tv. It shows me "3840x2160 4k 16:9 HDR(HDR10)" when things work correctly for my test videos, both with the old and new builds. I'm fairly sure Bravia HDR Mode is HDR10 (not HLG) and color space is BT.2020 (not BT.709, DCI, or Adobe RGB). This is based on visually observing the difference between these modes and AUTO. This appears to be the case for both old and new builds... So as far as I can tell both builds are attempting to use the same color settings.
But I think its safe to deduce the newer builds are doing something different that is incompatible with my denon...
According to the links below my denon avrx4300h should be compatible with all the modes. I followed all the troubleshooting steps including using input-cd, updating firmware, etc. Nothing worked for me.
I have an AVR-X2400H - I had to enable Enhanced HDMI support on both my TV and my AVR, and have to use HDMI 2 or HDMI 3 on my TV to allow 4:2:2 12-bit 2160p50/59.94 support. (HDMI 1 and HDMI 4 are 4:2:0 only - which the Pi won't support at 2160p50/59.94)
HDMI 3 is my ARC port so that makes sense anyway.