ARTICLE: Which HDMI cable should I use for 4K HDR?

GhostRider17

Well-known Member
Excellent thread,a great read and explains things well for people unsure.
 

boabis

Active Member
Be sure to buy gold-plated cables, as the molecular structure of gold takes the form of a microscopic net, which stops stray 1s and 0s from escaping.
 

roydonaldson

Novice Member
I think it would be worthwhile specifying HDMI cables with Ethernet in them just now. As the new eARC feature looks very useful for AV going forward and this uses the ethernet pins of a standard HDMI cable to provide the advanced eARC features:

HDMI 2.1 eARC Technology - Lattice Semiconductor
 

kitschcamp

Active Member
Roy, you've just sort of answered a question I was going to ask - does anything in the consumer space actually use the Ethernet channels on HDMI? To date I've never seen anything that mentions using it in the spec or manual.
 

Toon Army

Well-known Member
Roy, you've just sort of answered a question I was going to ask - does anything in the consumer space actually use the Ethernet channels on HDMI? To date I've never seen anything that mentions using it in the spec or manual.
The Denon AVR-X4400H is eARC enabled.
 

PC1975

Well-known Member
Thanks Steve, for a really useful article. I hear of so many people who are told by shop assistants that they need to upgrade their hdmi cables for their new tvs - and inevitably end up doing so. I wasn't sure myself and thought hdr or at least dynamic hdr would require new cables but that doesn't seem to be the case.
 
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raoulx

Active Member
Great article and always nice to learn something new :)
 

jfinnie

Distinguished Member
From:
https://www.hdmi.org/manufacturer/hdmi_2_1/

Ultra High Speed HDMI Cable

Q: What is the maximum length of this cable?
A: The specification does not indicate a cable length. Cable length depends on the cable manufacturer. It is likely the maximum lengths for passive cables will be approximately 2 to 3 meters.

Q: Are active cables supported in the specification?
A: The specification permits wire, passive, active, and converter Category 3 cable assemblies.
2-3 meters? Fuggedaboudit. It looks like if you're buying copper cables over 2-3m in length at the moment you're going to be completely out of luck for HDMI2.1, so best not buy anything expensive as you're going to be throwing it away pretty soon.

Hope they properly spec some active solutions soon...
 

Keagan

Novice Member
I'm confused, 10' of wire is too much to run from TV to any AV? What's the recommended length?
 

Joe Fernand

Distinguished Member
AVForums Sponsor
'I'm confused, 10' of wire is too much to run from TV to any AV? What's the recommended length?'

Back on the 4th Jan 2017 when HDMI.org first announced HDMI 2.1 the press release mentioned 48G cables and in additional Press statements mentioned an expected max length of up to 3m!
HDMI :: Press Release

Once HDMI 2.1 was formalised on 28th Nov 2017 the 48G cable naming had been dropped in favour of 'Ultra High Speed" and no indication of the expected cable length limitations for copper cables.
HDMI :: Press Release

Current generation High Speed and Premium High Speed Certified cables top out at 8m (26') - once the Certification process has been released cable manufacturers can start to release details on expected cable lengths for Copper, Active and Fibre solutions.

Expect anything much longer than a few meters to be Active or Fibre based.

Joe
 

jfinnie

Distinguished Member
Back on the 4th Jan 2017 when HDMI.org first announced HDMI 2.1 the press release mentioned 48G cables and in additional Press statements mentioned an expected max length of up to 3m!
HDMI :: Press Release

Once HDMI 2.1 was formalised on 28th Nov 2017 the 48G cable naming had been dropped in favour of 'Ultra High Speed" and no indication of the expected cable length limitations for copper cables.
HDMI :: Press Release
The current FAQ still says to expect somewhere between 2-3m max for copper passive cables. Really hope they properly spec and certify a fibre solution so everyone can know exactly what they're getting. Apart from anything, it will also solve the certification issue for people wanting a certified solution for 18gbps >8m, which just doesn't exist.
 

Keagan

Novice Member
'I'm confused, 10' of wire is too much to run from TV to any AV? What's the recommended length?'

Back on the 4th Jan 2017 when HDMI.org first announced HDMI 2.1 the press release mentioned 48G cables and in additional Press statements mentioned an expected max length of up to 3m!
HDMI :: Press Release

Once HDMI 2.1 was formalised on 28th Nov 2017 the 48G cable naming had been dropped in favour of 'Ultra High Speed" and no indication of the expected cable length limitations for copper cables.
HDMI :: Press Release

Current generation High Speed and Premium High Speed Certified cables top out at 8m (26') - once the Certification process has been released cable manufacturers can start to release details on expected cable lengths for Copper, Active and Fibre solutions.

Expect anything much longer than a few meters to be Active or Fibre based.

Joe
Thanks for the clarification Joe, thought my 10' cables were useless.
 

Rock Danger

Distinguished Member
Arrow-AV did a big real world test on a bunch of cables here:

http://www.avsforum.com/forum/168-h...ly-support-18gbps-hdmi-2-0b.html#post52755273

Which made buying my PJ cable really easy and any other cable I needed as a matter of fact. He's the only person I know that will test this stuff thoroughly in actual setups as well as lab equipment.

So it saved me having to do a bunch of research and madness cause it's all there in a big nerd file.
 

AWCrypt

Novice Member
Hi does anyone know what HDMI cables I need to achieve 4K 60FPS HDR10 content with the 4:4:4 Chroma??? I've bought so many 18Gbps Certified HDMI 2.0 cables now and NONE of them go past 4:2:0 Chroma. It's becoming very annoying now and I'm beginning to think HDMI 2.0 cables are a giant con!!

I have an LG OLED TV and am using an RTX2070 graphics card to create the graphics content. The LG TV is capable of achieving 4K at 120FPS 4:4:4 HDR pictures, and the RTX2070 graphics card is only running at about 14% capacity so all of my hardware is fully capable, it's just the HDMI cable that's proving to be the weak link.

All of the Certified HDMI 2.0 cable adverts say they can do 4K and HDR and 4:4:4 blah blah blah but I don't care which of the settings the cable can achieve in isolation with all of the other settings turned down, because I want the cable to support all of those settings at the same time like my expensive TV and my expensive computer are capable of displaying :(

Please help. I've even purchased 27Gbps and 48Gbps HDMI cables and although those definitely work better than the 18Gbps ones, they were both only still able to get me to 4K 60FPS HDR12 4:2:2 Chroma... I mean HDR12 doesn't even exist yet does it, except in Dolby Vision, but I think my TV is only HDR10 so cannot make use of this extra HDR12 content :(

I mean do HDMI 2.0 ports on TV's max out at 4K 60FPS HDR 4:2:2 Chroma or something??? I've not read that anywhere but is that going to be the maximum performance I can get out of this TV until TV's with V2.1 HDMI ports start being sold???
 

raoulx

Active Member
I'm probably mixing up a few things here @AWCrypt and it's a different concept but I recently saw a Linus Tech tips video about 8K and HDMI cables and being able to provide some useful information, more so in the 2nd video link.

then a subsequent video about gaming at higher resolution
where by limitations on cables/adapters were a big problem and using a special cable allowed them to run as they wanted. I'm at work so I can't watch at which point it was resolve or what was said, but there maybe some information on here which could help. Mainly cable and adapter or a pre-adapted cable to fulfil higher bandwidth content
 

Rock Danger

Distinguished Member
4:4:4 4k HDR would require 20+ Gbps - HDMI 2.0 taps out at 18Gbps that's why. Why do you think you need above 4:2:0 or 4:2:2??
 

gibbsy

Moderator
Isn't 4:4:4 HDMI 2.1 territory?
 

hodg100

Distinguished Member
Hi does anyone know what HDMI cables I need to achieve 4K 60FPS HDR10 content with the 4:4:4 Chroma??? I've bought so many 18Gbps Certified HDMI 2.0 cables now and NONE of them go past 4:2:0 Chroma. It's becoming very annoying now and I'm beginning to think HDMI 2.0 cables are a giant con!!

I have an LG OLED TV and am using an RTX2070 graphics card to create the graphics content. The LG TV is capable of achieving 4K at 120FPS 4:4:4 HDR pictures, and the RTX2070 graphics card is only running at about 14% capacity so all of my hardware is fully capable, it's just the HDMI cable that's proving to be the weak link.

All of the Certified HDMI 2.0 cable adverts say they can do 4K and HDR and 4:4:4 blah blah blah but I don't care which of the settings the cable can achieve in isolation with all of the other settings turned down, because I want the cable to support all of those settings at the same time like my expensive TV and my expensive computer are capable of displaying :(

Please help. I've even purchased 27Gbps and 48Gbps HDMI cables and although those definitely work better than the 18Gbps ones, they were both only still able to get me to 4K 60FPS HDR12 4:2:2 Chroma... I mean HDR12 doesn't even exist yet does it, except in Dolby Vision, but I think my TV is only HDR10 so cannot make use of this extra HDR12 content :(

I mean do HDMI 2.0 ports on TV's max out at 4K 60FPS HDR 4:2:2 Chroma or something??? I've not read that anywhere but is that going to be the maximum performance I can get out of this TV until TV's with V2.1 HDMI ports start being sold???
Assuming you have one of the 2019 LG OLEDs with (some) HDMI 2.1 features enabled...Have you tried all the HDMI inputs? ISTR only one of the ports is '2.1'..

EDIT: Or maybe that was eARC.

Still, worth a try if you haven't already.
 

AWCrypt

Novice Member
@raoulx Cool video!! I want an 8K screen now LOL but will have to wait until they get cheaper, and until graphics cards get better and all those other connectivity glitches have been ironed out.

It does however look like HDMI ports themselves may be responsible for maxing out at a certain bandwidth though otherwise why would Sharp's 8K TV require 4x concurrent HDMI inputs to give 8K resolutions at 60Hz.....

But if that is the case then why make 48Gbps HDMI cables at all??? Unless Sharp's TV only has the older HDMI 2.0 HDMI ports and has not yet moved to a "single" HDMI 2.1 port.

I'd like to know the answer to this question :)
 

AWCrypt

Novice Member
@gibbsy Noooo LOL. 4:4:4 is like the same as RGB and RGB has been around since before the 1980's !!

That's what I'm wondering though, maybe 4:4:4 when run in that mode at the "same time" as HDR + 4K + 60Hz is beyond the capabilities of HDMI 2.0 ports !!
 

AWCrypt

Novice Member
4:4:4 4k HDR would require 20+ Gbps - HDMI 2.0 taps out at 18Gbps that's why. Why do you think you need above 4:2:0 or 4:2:2??
Because Chroma is really important. I mean If you operate a 4K TV at 4:2:0 Chroma then all you've really achieved is to turn an expensive 4K screen into a 1080P resolution!

So for movies and PC text work it would be better to operate at 4:4:4 Chroma and lower FPS settings so you get all that extra resolution coming through, but for high speed racing games ir going to be better to have higher FPS at the expense of Chroma... but for high speed shooting games where you really need the best of both worlds with high FPS and high effective resolution you would be better to drop the HDR in favour for lower bitrate colour gamuts, but then the game will become less colourful and so more boring to play. It just seems like it's all a huge compromise at the moment but hopefully v2.1 brings 4K to where it should be.

I think we'll all need to wait until HDMI v2.2 or beyond before we'll see great performance out of an 8K screen through a single cable, but innovations like Sharp's 4 in 1 concurrent HDMI setup are definitely going to help provide performance to those who can afford 4x graphics cards!

:)
 

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