Does Iris Xe support DSC and 8K@60hz 4:4:4 resolution?

[frisbfreek]

I'm trying to achieve 8K@60hz 4:4:4 chroma output with the setup below:

• X1 Carbon 9th Gen with Core i7-1185G7 and Iris Xe graphics. Iris Xe specs claim that it supports one 8K@60hz display.
  • I'm running Intel Graphics Driver 30.0.100.9955. This driver version gets 8K (@60hz 4:2:0), but updating to the "latest" version kills 8K compatibility altogether.
• USB-C to HDMI 2.1 adapter (Club 3D CAC-1586). Specs for this device claim that it also supports 8K@60hz 4:4:4 and DSC.
• Samsung QN800A 8K TV. I know the QN800A can do 8K@60hz 4:4:4, as I can achieve this using a RTX 3060 Ti with native HDMI 2.1 output.

The thing is that I can only get 8K@60hz 4:2:0 chroma (not 4:4:4 chroma) or 8K@30hz 4:4:4. Both of these are half the bandwidth of full 8K@60hz 4:4:4, and the last one is the only one that requires DSC.

Does Iris Xe actually support full 8K@60hz 4:4:4? Does it support DSC at all?

Thanks in advance!

[Paraddi]

I am also investigating to check the support of 5K@120Hz , surprising to see no response to this thread since July 2022 😞

[MUC]

Display Stream Compression (DSC) is supported starting with 11th Generation Intel Core Processor Graphics (also known as Tiger Lake) and newer.

In November last year we verified the possibilities of a processor integrated Intel UHD770 in a NUC 13 Extreme. With this cable, the UHD770 operates the Samsung Odyssey G95NC at 7680 x 2160 @ 120 Hz. Unfortunately, I can't find the relevant thread anymore. It was probably in the NUC section, but that was removed when the NUC business was transferred to ASUS.

• 7680 x 2160 @ 120 Hz = 199 % DisplayPort HBR3 (with DSC OK)
• 5120 x 2880 @ 120 Hz = 179 % DisplayPort HBR3 (with DSC OK)

The Club 3D CAC-1586 adapter mentioned above contains the Synaptics VMM7100 Protocol Converter (PCON) chip DisplayPort HBR3 > HDMI 2.1 Fixed Rate Link (FRL). I have successfully tested the following on Tiger Lake Iris Xe from 2021 to the 8K projector JVC DLA-NZ8:

• 4K @ 120 Hz RGB 10 bpc HDR (40 Gbps)
• 8K @ 60 Hz YCbCr 4:2:0 8 bpc (32 Gbps)
• 8K @ 30 Hz RGB 10 bpc HDR (40 Gbps)

HBR3 DSC compressed streams are either decoded and then forwarded uncompressed on the HDMI side. Or the DSC stream is passed through. As tested with the Nvidia RTX A2000 (Ampere) on JVC DLA-NZ8:

• 4K @ 120 Hz RGB 10 bpc = 129 % HBR3 (CVT-RB) = 100 % FRL5 (CTA-861)
• 8K @ 60 Hz RGB 12 bpc = 294 % HBR3 (CVT-RB) = 241 % FRL5 (CTA-861)

I can therefore confirm that Nvidia graphics cards can do more than Intel graphics in conjunction with this PCON.

The DSC decoder in the VMM7100 supports fractional compression ratios of 2:1 and 3:1 up to 12 bpc. However, the translation from VESA Adaptive Sync to HDMI Variable Refresh Rate (VRR) does not work with the VMM7100 yet with publicly available firmware.

[toriko]

Hi MUC, since you seem quite knowledgeable and for some reason I can't direct message people on this platform I was hoping to ask a quick question by replying. I know the VMM7100 is unable to do VRR though I was curious if the Realtek RTD2173, which I believe is used in the arc limited edition cards, is able to do so. It seems to be the case since in an intel article they advertise it can, "The Intel® Arc™ A770 Limited Edition and A750 Limited Edition Graphics offer an HDMI 2.1 output with support for variable refresh rate". Though I couldn't find an answer publicly and was hoping you could clarify given your knowledge of the situation.

[MUC]

I tested quite a few adapters looking for the best solution. To my knowledge, there are the following active protocol converter chips:

1. Synaptics VMM7100 (predecessor VMM6100)
2. Realtek RTD2173
3. Parade Tech PS196

The RTD2173 is used by Intel on their own Arc Limited Edition board to provide HDMI 2.1 Fixed Rate Link (FRL). It is fed by the DisplayPort main link from the GPU. See this. But in external adapters this chip did not convince. Embedded in adapter housings, it often has a problem with heat build-up and then becomes unstable. But there are people who have already equipped these adapters with cooling fins and allegedly had better success then. I tested this one. It did not provide HDMI VRR.

However, Intel states that HDMI VRR works if the display device is HDMI 2.1: Variable Refresh Rate (VRR) 'Not Supported' in Intel Arc Control. I haven't tested an Intel Arc Limited Edition card, so I can't confirm it myself. Please note that there are cards from other manufacturers that have the VMM7100 on the circuit board, e.g. ASRock Arc A750 Challenger:

I cannot say whether the information in the Intel troubleshooting article also applies to these cards. I have not tested a card like this either.

The PS196 is almost unavailable on the market. I tested this cable. With the Intel Arc A380, the cable works well with TMDS up to 4K @ 60 Hz. FRL for higher refresh rates is usually not present and if it is, then the picture has small optical errors. However, this cable works very well with the Nvidia RTX A2000. One could therefore assume that Intel's interface compatibility is somewhat worse than that of Nvidia. Adaptive Sync is grayed out although HDMI VRR is reported by the EDID. To my knowledge, HDMI VRR does not work properly with any adapter or converter cable on any GPU brand. This cannot be attributed solely to the GPU anyway, since the display also plays a major role.