HDMI 2.1 improves input lag?

Everything about latency. This section is mainly user/consumer discussion. (Peer-reviewed scientific discussion should go in Laboratory section). Tips, mouse lag, display lag, game engine lag, network lag, whole input lag chain, VSYNC OFF vs VSYNC ON, and more! Input Lag Articles on Blur Busters.
Post Reply
Jonnyc55
Posts: 19
Joined: 15 Jan 2024, 08:09

HDMI 2.1 improves input lag?

Post by Jonnyc55 » 09 Jun 2024, 11:56

I've seen no talk about HDMI 2.1 and input lag on the internet yet, yet the HDMI website says:
HDMI 2.1 also helps reduce display input lag (latency)

The first monitors came in 2020, prices are still a bit silly; Cheapest being like £400 from AOC.

https://www.hdmi.org/blog/detail/124:
HDMI 2.1 also helps reduce display input lag (latency) and power consumption with its Auto Low Latency Mode (ALLM) and Quick Frame Transport (QFT) features.
https://www.hdmi.org/spec/hdmi2_1:
Enhanced gaming features ensure an added level of smooth and seamless motion and transitions for gaming, movies and video.More Info... They include:

Variable Refresh Rate (VRR) reduces or eliminates lag, stutter and frame tearing for more fluid and better detailed gameplay.More Info...
Auto Low Latency Mode (ALLM) allows the ideal latency setting to automatically be set allowing for smooth, lag-free and uninterrupted viewing and interactivity.More Info...
Quick Frame Transport (QFT) reduces latency for smoother no-lag gaming, and real-time interactive virtual reality.More Info...
I've not looked into VRR, not sure if that effects input lag or just screen tearing?

(This is the link from "More info...",) Auto Low Latency Mode (ALLM): https://www.hdmi.org/spec21sub/autolowlatencymode :
Auto Low Latency Mode (ALLM)

Auto Low Latency Mode enables the ideal latency setting to automatically be set allowing for smooth, lag-free and uninterrupted viewing and interactivity. In many cases this is referred to as game mode, and it usually has to be set manually which involves going through menus and settings and then switching back again for normal viewing.

ALLM lets a game console, PC or other device send a signal to the display which will cause it to automatically switch to a low-latency, low-lag mode for gaming. This could benefit other uses, such as karaoke and video conferencing too.

ALLM

But a low latency setting may not be ideal for other types of viewing since some processing features on a TV may be stopped in order to reduce latency. So with ALLM when the source no longer requires this mode—for example, when switching to a movie stream—the source disables the signal and the display reverts back to its previous mode for optimal picture.

For additional Enhanced Gaming Features check out: Variable Refresh Rate and Quick Frame Transport

(This is the link from "More info..." HDMI® Quick Frame Transport (QFT): https://www.hdmi.org/spec21sub/quickframetransport :
HDMI® Quick Frame Transport (QFT)

Another highlight from the HDMI 2.1b specification’s multiple gaming and media features is Quick Frame Transport. QFT reduces latency for smoother no-lag gaming, and real-time interactive virtual reality.

QFT transports each frame at a higher rate to decrease “display latency”, which is the amount of time between a frame being ready for transport in the GPU and that frame being completely displayed. This latency is the sum of the transport time through the source’s output circuits, the transport time across the interface, the processing of the video data in the display, and the painting of the screen with the new data. This overall latency affects the responsiveness of games, such as how long between a button is pressed to the time at which the resultant action is observed on the screen.

While there are a lot of variables in this equation, not many are adjustable from an HDMI specification perspective. QFT operates on the transport portion of this equation by reducing the time it takes to send only the active video across the cable. This results in reduced display latency and increased responsiveness.

For additional Enhanced Gaming Features check out: Variable Refresh Rate and Auto Low Latency Mode
I'll add the VRR one too:
HDMI® Variable Refresh Rate (VRR)

One of the highlights from the HDMI 2.1b specification’s multiple gaming and media features is Variable Refresh Rate. VRR reduces or eliminates lag, judder and frame tearing for more fluid and better detailed gameplay. VRR enables a gaming source such as a console or computer to deliver video frames as fast as it can, which in many cases is slower than the normal static refresh rate.

VRR 3

Graphics processors require different absolute periods to render each frame, and this time is dependent upon the complexity of the scene, the horsepower of the GPU, the resolution selected and the frame rate. When the GPU is taxed by the other three factors and does not finish rendering the next frame by the time it needs to be displayed, the source must either repeat the current frame or display the partially-rendered next frame, which causes judder and tearing.

By waiting until the next frame is ready to transport it, a smoother gaming experience can be provided to the user.

For additional Enhanced Gaming Features check out: Auto Low Latency Mode and Quick Frame Transport
I reckon others are better at understanding this. Does this help reduce input lag? Or just make things look smoother?

Thanks.

User avatar
Slender
Posts: 1576
Joined: 25 Jan 2020, 17:55

Re: HDMI 2.1 improves input lag?

Post by Slender » 10 Jun 2024, 10:37

i dont know but im notice my 60hz TV is more responce then xl2566k, idk.why.
tv - hdmi
monitor - displayport

Sandy
Posts: 129
Joined: 30 Mar 2024, 02:14

Re: HDMI 2.1 improves input lag?

Post by Sandy » 10 Jun 2024, 12:30

Slender wrote:
10 Jun 2024, 10:37
i dont know but im notice my 60hz TV is more responce then xl2566k, idk.why.
tv - hdmi
monitor - displayport
I discovered this a long time ago, so I use 75Hz to play CS

Jonnyc55
Posts: 19
Joined: 15 Jan 2024, 08:09

Re: HDMI 2.1 improves input lag?

Post by Jonnyc55 » 25 Jun 2024, 11:56

Slender wrote:
10 Jun 2024, 10:37
i dont know but im notice my 60hz TV is more responce then xl2566k, idk.why.
tv - hdmi
monitor - displayport
Sandy wrote:
10 Jun 2024, 12:30
Slender wrote:
10 Jun 2024, 10:37
i dont know but im notice my 60hz TV is more responce then xl2566k, idk.why.
tv - hdmi
monitor - displayport
I discovered this a long time ago, so I use 75Hz to play CS
Very interesting. I checked that monitor, wow, expensive with high HZ, good specs. I wonder if there is some shortcoming in the sheer complexity of managing very high refresh rates, whereby engineers can just about pull it off, note, JUST ABOUT i.e. not highly refined/highly stable. So this tech could be pushed out on a premature basis or forced out just for high refresh rate numbers just to appease tech companies and consumers for profits. Profit seeking aside, I reckon the complexity to stabilise high refresh rates may have some very immature engineering at the moment, or even there is some physics consequences that manifest in other ways due to the very high refresh rates.

It'll be interesting if anyone has any expertise in this area who can talk of the nature of very high refresh rates like 240hz 360hz etc. if there is any artifact-shortcomings in anyway with very high refresh rates.

User avatar
Slender
Posts: 1576
Joined: 25 Jan 2020, 17:55

Re: HDMI 2.1 improves input lag?

Post by Slender » 25 Jun 2024, 13:17

Jonnyc55 wrote:
25 Jun 2024, 11:56
Slender wrote:
10 Jun 2024, 10:37
i dont know but im notice my 60hz TV is more responce then xl2566k, idk.why.
tv - hdmi
monitor - displayport
Sandy wrote:
10 Jun 2024, 12:30
Slender wrote:
10 Jun 2024, 10:37
i dont know but im notice my 60hz TV is more responce then xl2566k, idk.why.
tv - hdmi
monitor - displayport
I discovered this a long time ago, so I use 75Hz to play CS
Very interesting. I checked that monitor, wow, expensive with high HZ, good specs. I wonder if there is some shortcoming in the sheer complexity of managing very high refresh rates, whereby engineers can just about pull it off, note, JUST ABOUT i.e. not highly refined/highly stable. So this tech could be pushed out on a premature basis or forced out just for high refresh rate numbers just to appease tech companies and consumers for profits. Profit seeking aside, I reckon the complexity to stabilise high refresh rates may have some very immature engineering at the moment, or even there is some physics consequences that manifest in other ways due to the very high refresh rates.

It'll be interesting if anyone has any expertise in this area who can talk of the nature of very high refresh rates like 240hz 360hz etc. if there is any artifact-shortcomings in anyway with very high refresh rates.
I think no.
There's another reason why 60Hz feels better than 360Hz, it's not a monitor, it's not a high refresh rate, and it's not a displayport.
For example, yesterday I tried to play on a PC and a monitor without grounding (I just used an extension cord without grounding) I got graphical artifacts, textures that appeared out of thin air when you get close to them and a loss in control and smoothness.

Sandy
Posts: 129
Joined: 30 Mar 2024, 02:14

Re: HDMI 2.1 improves input lag?

Post by Sandy » 25 Jun 2024, 13:49

Sandy wrote:
10 Jun 2024, 12:30
Slender wrote:
10 Jun 2024, 10:37
i dont know but im notice my 60hz TV is more responce then xl2566k, idk.why.
tv - hdmi
monitor - displayport
I discovered this a long time ago, so I use 75Hz to play CS
It may be different from what you think. I have been playing Cs1.6 with custom resolution 640*480 75Hz

Post Reply