LG 32un880-b 8bpc or 10bpc

[getheo]

Hello,

the moniror has 8bit+frc panel. When I connect my macbook pro 2019 15.4 with usb-c to hdmi cable and run

cd /System/Library/Extensions/AppleGraphicsControl.kext/Contents/MacOS
./AGDCDiagnose -a

I get

DisplayPort Version 12
Link Clock 540000 kHz
Link Bits 24 bpc
Refresh Rate (Calculated) 60 Hz
Window (Active) 3840 x 2160
Window (Scaled) 6016 x 3384
Pixel Clock 594000000 Hz
Pixel Encoding 2 (YCbCr444)
Bits Per Color Component 2 (8 bpc)

which shows 8 bits per color. If I connect it with usb-c to usb-c, is it possible to get 10bpc? Can someone run the same commands if he has 8bit+frc monitor and check the results?

 

[joevt]

594 MHz is a HDMi 2.0 timing for 4K. HDMI can't do 10bpc without switching from 4:4:4 to 4:2:2 or 4:2:0 chroma sub sampling or by using a lower refresh rate that reduces the pixel clock to below 480 MHz.

DisplayPort 1.2 has more bandwidth than HDMI 2.0 so it will be able to do 4K60 10bpc RGB which should also allow HDR mode. DisplayPort timing will be a more efficient 533 MHz for 4K (10bpc requires a pixel clock lower than 576 MHz).

AGDCDiagnose can't tell the difference between a 10bit and 8bit+frc panel.

 

[getheo]

Thanks for the answer,

I tried 30Hz and AGDCDiagnose showed 10bpc. How can I check if the YcRcB or RGB is limited(16-235) or not? Does AGDCDiagnose show it?

AGDCDiagnose can't tell the difference between a 10bit and 8bit+frc panel.

If the panel is 8 bits, does the macbook send 8bit or 10bit signal?

 

[joevt]

I tried 30Hz and AGDCDiagnose showed 10bpc. How can I check if the YcRcB or RGB is limited(16-235) or not? Does AGDCDiagnose show it?

I don't think I've ever seen a Mac send limited range YCbCr or RGB or I don't know how to detect limited/full range quantization. AGDCDiagnose shows the following:
Dynamic Range (SDR, HDR10, DolbyNormalMode, DolbyTunnelMode, TraditionalGammaHDR, TraditionalGammaSDR),
Colorimetry (Native RGB, sRGB, DCIP3, AdobeRGB, xvYCC, WGRGB, BT601, BT709, BT2020, BT2100).
I don't know if it can show limited range.

There's a kIODisplayColorModeRGBLimited flag for kConnectionColorMode of IODisplayAttributes but I don't know when it gets set or if it applies or if it is accurate. The AllRez command can parse these flags from the I/O Registry. #177 But there's no corresponding YCbCr limited flag. Here's some info https://referencehometheater.com/2014/commentary/rgb-full-vs-limited/
There's analog signal levels: 0700_0300, 0714_0286, 1000_0400, 0700_0000 measured in mV but you're talking about digital values...

If the panel is 8 bits, does the macbook send 8bit or 10bit signal?

It sends the bpc that you see in AGDCDiagnose. If the MacBook sends 10bpc and the panel is 8 bits, then the panel can ignore the two least significant bits or use them for FRC or some dithering method.