Originally Posted by claw
I don't think this is the case when the device that the Oppo outputs to does not support 4K or HDR. We discussed this earlier and I posted that my Samsung K8500 UHD player would not send HDR if the Oppo output was to a non-HDR device. I did not test 1080p, but I expect the same would be true when the Oppo output is connected to a 1080p device.
I think the Oppo is required to report the display device's capabilities just like an AVR would.
That's actually an issue with Copy Protection, and how strictly the Source device decides it wants to implement that.
Most 4K/HDR content is going to want HDCP 2.2 Copy Protection. HDMI is an end to end protocol, and so every device in the video chain has to be HDCP 2.2 compliant or the source won't send 4K/HDR into the video chain. What the source sends INSTEAD is up to the Source.
For example, if I attach an Apple TV 4K to the HDMI Input of my 205, and cable Main HDMI out of the 205 to my Anthem Statement D2v/3D -- which is only capable of 1080p (w/ 3D) and no HDR, with the D2v cabled to my LG E6, I'll need to set the OPPO to output 1080p so my D2v can handle that.
I can still set the HDMI Input Specifications to UHD HDR. And HDR output to AUTO.
Now, when I select the HDMI Input on the OPPO and play, say "Arrival" in iTunes on the ATV4K the following logic happens:
1) The movie is 4K / Dolby Vision, so the ATV4K is looking for the video chain to be HDCP 2.2 compliant. It sends a query to the OPPO and discovers it is good to go. It then sends a query through the OPPO to the D2v and discovers it is NOT HDCP 2.2 compliant. (It doesn't matter whether the LG E6 has HDMI Ultra HD Deep Color enabled or not for the input from the D2v -- which is how you enable HDCP 2.2 in the LG.)
2) The ATV4K identifies the content it wants to play as HDCP 2.2 Class 1, which means it is not legal for the OPPO to convert HDCP 2.2 input to lesser Copy Protection output.
3) The ATV4K then decides to try for HDCP 2.1. It can send 4K with that, but not HDR. After inquiring of the OPPO, and the D2v, it discovers that the OPPO is capable of HDCP 2.1 but the D2v is not. (Again it does not matter at this point what the LG can do.)
4) The ATV4K decides the SDR-restricted content *IS* OK for down-conversion. I.e., it can be sent as 4K SDR, and the OPPO is allowed to down-convert that to 1080p to go to the D2v -- assuming the rest of the video chain is compliant with HDCP 1.4.
5) The ATV4K then inquires of the D2v (through the OPPO, and the LG E6 (through both the OPPO and the D2v) and discovers that they are both good for HDCP 1.4, and furthermore that the LG E6 is the end of the video chain.
The RESULT of all this handshaking is that the ATV4K sends 4K/SDR to the OPPO (HDCP 2.1). The OPPO down-converts that to 1080p/SDR to the D2v (HDCP 1.4). And the D2v passes that on to the LG E6 still as 1080p/SDR.
I have my ATV4K set to match both frame rate and dynamic range between content and output. It can't match the Dolby Vision dynamic range of the movie because the HDMI Input of the OPPO does not accept Dolby Vision at this point. And it can't even convert that to HDR-10 output due to the lack of HDCP 2.2 compliance in the entire video chain. But it CAN match the /24 frame rate.
And so the ATV4K takes this 4K/24 Dolby Vision flick and outputs it to the OPPO as 4K/24 SDR BT.709 YCbCr 4:4:4 8-bit. The ATV4K is doing the down-conversion from Dolby Vision to SDR (including the down-conversion of Color Gamut to BT.709). The choice of 4:4:4 8-bit output has to do with how 4K output works in HDCP 2.1 to keep from exceeding the HDMI bandwidth limit for HDCP 2.1 connections.
The OPPO (with my standard settings) then does its down-conversion and outputs 1080p/24 SDR BT.709 YCbCr 4:2:2 12-bit to the D2v.
The D2v then sends along 1080p/24 to the LG E6 -- still as SDR.
Again, all of this is true whether or not HDMI Ultra HD Deep Color (HDCP 2.2 style video) is enabled in the LG E6 or not.
The bottom line being the ATV4K will send this movie as 4K to the OPPO but will convert the Dolby Vision to SDR.
OTHER Source devices may make different choices.