Link Copied
Is that roughly correct?
- Please check whether there is a firmware update for the TV.
- The troubleshooting instructions from the switch manufacturer are in the appendix.
- How long are the cables you use? A passive HDMI 2.0 copper cable should be no longer than 25 ft (7 meters). If possible, it should be a certified so-called “Premium High Speed HDMI Cable”.
- To check the Extended Display Identification Data (EDID), please create a Report for Intel Graphics Drivers on the PC with the Intel Arc A750 and attach it here.
TESmart writes in several places:
"With EDID emulators in each input port, keep PCs always having correct display information, prevent display settings from changing while switching input ports."
"With EDID emulators in each input port, the accuracy of the display information of PCs will be secured"
The EDID transmitted to the Intel Arc A750 demands a preferred use of 4K @ 30 Hz:
Video timing according to the Consumer Technology Association standard (CTA-861, VIC = 1) @ 297 MHz TMDS. This is still within the bandwidth of HDMI 1.4 (9 Gbps) and is therefore stable.
The EDID also contains:
Interoperability with a TV is best when the CTA standard is followed.
I suspect that the driver is trying to send the signal using Coordinated Video Timing - Reduced Blanking (CVT-RB) version 2.
To see where the above data comes from, please do the following:
- Please create a Report for Intel Graphics Drivers with the laptop and attach it.
- Please connect the Intel Arc A750 directly to the TV and create a Report for Intel Graphics Drivers and attach it as well.
I can establish a signal with CTA video timing on my Intel Iris Xe (31.0.101.5522) using the EDID in question with 60 Hz selected. So I understand the behavior of your laptop.
I have now looked at an EDID of a Vizio TV from 2019. The preferred resolution of 4K @ 30 Hz is also there. However, the 58 Hz CVT-RB v2 parameters are not. These seem to be added by the TESmart device, but unlike your laptop, they are not compatible with the signal path of your Arc A750 graphics card.
Please try the following:
- Download Custom Resolution Utility (CRU) to the PC with the Arc A750
- Run CRU.exe
- Make sure the active EDID is that of the TV. If necessary, select from the drop down menu.
- Delete the CVT-RB v2 entry with 58 Hz.
- Close CRU with OK and restart the computer.
If that works, it is probably due to the HDMI port on the Arc A750. There are manufacturers on the market that use a PCON chip on the Printed Circuit Board for this. What brand is your graphics card?
HDMI cables are often the cause of the behavior described. It is therefore always a good idea to check.
From the data you have attached, I can see the following differences:
The connection type does not necessarily mean anything. Chips on the respective circuit boards are often the cause. What is interesting, however, is that the Iris Xe video timing parameters for 58 Hz correspond to the CVT-RB version 1 standard. Since the display identification for the Arc A750 remains the same after being connected directly to the TV (M437-G0), the driver also uses the same EDID from the Windows registry as before, CVT-RB v2. I therefore agree with your conclusion that the problem is not due to the video timing.
If you want to check it yourself, I can recommend the following resources:
Raw EDID Decoding
Video Timings Calculator
To "clean up" you can run the following from the CRU download:
This will delete all display EDIDs from the Windows registry. On reboot the connected devices will be recreated.
If the display device can handle it, the idea of using CVT-RB for transmission is basically correct in a difficult cable situation (old, long, laid in the wall and therefore subject to interference), as the required bandwidth will drop.
4K @ 60 Hz 4:4:4 CTA-861 = 18 Gbps (594 MHz, HDMI 2.0 MAX)
4K @ 60 Hz 4:4:4 CVT-RB v1 = 16.16 Gbps (533.28 MHz)
4K @ 60 Hz 4:4:4 CVT-RB v2 = 15.84 Gbps (522.62 MHz)
The reason the CTA video timing seems a bit wasteful is that during the blanking periods audio is transmitted, which can be quite demanding in consumer electronics over HDMI, e.g. Dolby Metadata-enhanced Audio Transmission (MAT). If you don't need audio, there's nothing wrong with using CVT-RB if the TV can handle it.
