DP 1.4 to FULL HDMI 2.1

jfreund

[H]ard|Gawd
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Sep 3, 2006
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I've got a PC with a 6800 XT (1 HDMI 2.1, 3 DP 1.4a) to connect to my TV/receiver. TV is a C1 OLED that can do 4K 120 Hz Freesync. The receiver won't pass through any video over 4K 60 Hz and no VRR. So, I need separate connections to the TV and receiver.

I got a DP to HDMI cable and it will do 4K 120Hz to the TV, but no VRR. When I connect it to the receiver, it shows up in Control Panel > Sound as an available audio device, but there is no sound when it is selected.

Anybody know an adapter that will get actual HDMI 2.1 features from DP 1.4? Or at least EITHER audio OR 4K 120 Hz VRR?
 

TrunksZero

Limp Gawd
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Jul 15, 2021
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My best guess, you probably need what is called an "Active DP 1.4 to HDMi 2.1" adapter. Club3D would be a brand I would generally recommend. But you might be able to find more affordable options :)
 

LukeTbk

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Could you use the HDMI passthrought of your TV instead of the receiver to the TV way ?

HDMI from the 6800xt to the TV second cable from the TV to the receiver ?



The C1 seem to have an 2.1 eARC passthrought port:
  • HDMI Audio Return Channel (ARC)
  • eARC (HDMI 2)
 

kasakka

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There is nothing out there that supports DP -> HDMI 2.1 conversion with VRR to my knowledge.
 
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jfreund

[H]ard|Gawd
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Could you use the HDMI passthrought of your TV instead of the receiver to the TV way ?

HDMI from the 6800xt to the TV second cable from the TV to the receiver ?



The C1 seem to have an 2.1 eARC passthrought port:
  • HDMI Audio Return Channel (ARC)
  • eARC (HDMI 2)

Thanks to Microsoft/Dolby, eARC (even optical out from the monitor) from Windows is limited to stereo, unless you buy the Atmos software from the MS Store. See below.
You're better off going for a DP to HDMI adapter for the audio. I use this one: https://www.amazon.com/gp/product/B017Q8ZVWK .

There is nothing out there that supports DP -> HDMI 2.1 conversion with VRR to my knowledge.
If VRR from DP is out, I'll settle for sound and run HDMI direct from the PC. Gonna try this cable when it arrives:

https://smile.amazon.com/gp/aw/d/B0B292WK3R?ref=ppx_pt2_mob_b_prod_image

Next stop will be an adapter as Tol suggested. I'm already using a 90° DP adapter (Meshlicious case, and yes I tried without the adapter), so I didn't want to daisy chain adapters. If it comes to it, that's what I'll have to do.

As a last resort, I have an old USB sound card that does Dolby Digital Live encoding.
 
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jfreund

[H]ard|Gawd
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Problem solved - Edt: kinda

The TV was set to output PCM over eARC, limiting it to 2 channels. Changing to "Bitstream" made 5.1 show up as a configuration option in Control Panel > Sound. Now I have to check this on the CX I have on another system.

One cable connection from PC with 4K 120Hz VRR and 5.1 to the receiver, just as God intended.

Edit: EXCEPT, every time I turn off the TV and turn it back on, the Radeon driver (both 22.5.1 WHQL and 22.7.1) crashes and the sound falls back to stereo until the PC is restarted. :banghead::mad:
 
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jfreund

[H]ard|Gawd
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Got this DP to HDMI cable in today. It DOES carry 4K 120Hz VRR and audio, too.

The weird thing is it works great going to the TV with HDMI direct from the video card to the receiver set as a second display. 5.1 sound works either from the HDMI or from the DP->HDMI via ARC. If I unplug the HDMI or, in Display Settings select "use only display 1" AND have VRR turned on in the Radeon driver the screen flickers and sound cuts out. Even with nothing using the HDMI connection, DP->HDMI only works with the HDMI cable connected if VRR is on.
 
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