AV receivers struggle with high frame rates over HDMI 2.1

Kate Wickens’s article last week in PC Gamer highlights a significant issue with graphics cards processing 4K/120 video output over an HDMI 2.1 connection. According to her report, while home cinema receivers from Denon, Marantz and Yamaha should be able to pass through video at both 4K/120Hz and 8K/60Hz over HDMI 2.1, it appears that such sources will only result in a blank screen.

With the launch of next-generation consoles carrying sophisticated graphics cards such as the Nvidia RTX 3070, RTX 3080 and AMD’s Big Navi (announced last week), there are a number of home cinema receivers with HDMI 2.1 connections currently unable to produce the full palette of features. PC Gamer also references tests conducted by c’t magazine via heise online and Tom’s Hardware on Denon AVR-X2700H models, which reveal a bug relating to onboard Panasonic chips. The same symptoms were apparent after routing Xbox Series X and Nvidia graphics cards through aforementioned receivers.

According to Wickens’s article, lower resolutions do pass through and function correctly but, as she points out, it somewhat defeats the object of the 2.1 specification. It does, however, appear that only models by manufacturers listed above are affected, and a regular connection direct to a display will not suffer.

Furthermore, the Xbox tested by c’t magazine was a pre-production unit but was based on final hardware designs. Yamaha products are also using the same chipsets as the Sound United models, so it is expected these will show up the same issues. Panasonic has told heise online that the problem “cannot be corrected with a firmware update” and it may be next year before replacements are made available.

 

 

Martin, a seasoned journalist and AV expert, has written for several notable print magazines. He’s served in key roles at Lucasfilm’s THX Division, NEC’s digital cinema division, and has even consulted for DreamWorks. Despite his illustrious career, Martin remains rooted in his passion for cinema and acting, with notable appearances in several Spielberg films, Doctor Who, and Star Wars: The Empire Strikes Back. He currently resides in San Francisco.

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AV Receiver HDMI Bug Update: Good News For PS5 And Nvidia Gamers - Forbes

Quote:
This week, though, Marantz and Denon owner Sound United has provided Stereonet with an update on the situation stating that according to its own extensive in-house testing, its new AVRs can in fact pass 4K at 120Hz from both the PS5 and, more surprisingly, Nvidia’s RTX 30 graphics cards.

When news of the new receivers’ HDMI issues first broke, it was thought likely then (before the consoles had arrived) that the PS5 wouldn’t be affected by the problem. But it’s still great to have this confirmed by Sound United (as well as numerous PS5 owners).

The Nvidia RTX 30 discovery, though, is more unexpected. According to the magazine c’t, which first reported the HDMI problem, Nvidia’s new cutting edge PC cards were expected to join the Xbox Series X in not passing 4K/120Hz properly through Denon and Marantz’s latest AVRs. Sound United is now not only able to state that this is not the case, however, but has released a (very useful) video explaining how to make sure your AVR and your Nvidia card are set up correctly to ensure there are no issues. A similar video for PS5 users can be found here.

During its tests, Sound United successfully got a Denon AVR-X2700H receiver to pass 4K/120Hz through from a PS5 and Nvidia RTX 3090 graphics card in all the formats you would expect. Namely RGB 8-bit, RGB 10-bit, YCbCr420 8-bit, YCbCr420 10-bit, and YCbCr420 12-bit.

If you know your graphics formats and are wondering why 4K/120Hz in 12-bit RGB isn’t on this compatibility list, it’s because the Denon and Marantz ‘8K compatible’ HDMI ports are designed to handle 40Gbps data rates rather than the 48Gbps data rates required to carry 12-bit RGB 4K/120Hz signals. This isn’t a problem, though, given that there are currently no 12-bit TVs out there. In fact, not even LG’s latest game-friendly X series of OLED TVs carry 48Gbps HDMIs, also choosing to stick instead at 40Gbps.
 
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