
Upcoming HDMI 2.1 Features - mfiguiere
http://hdmiforum.org/hdmi-forum-releases-version-2-1-hdmi-specification/
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ricardobeat
Finally we'll be able to switch between inputs without a 3-second delay! This
is one of my dream technology scenarios.

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kimburgess
QMS is unlikely to help with that. It appears to be targeted at allowing a
single device to vary its refresh rate or resolution without requiring a
complete disconnect/reconnect cycle.

The delay you're seeing is more likely caused by HDCP hand shaking and key
negotiation. Depending on your situation, there are external switchers that
handle key caching so you can switch cleanly - complete overkill for personal
user though as they are not cheap.

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Ajedi32
Wait, so slow HDMI switch times are caused by DRM?

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Sophistifunk
As a rule, _anything_ your modern TV setup does that seems frail or way too
slow is about DRM :(

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0xcde4c3db
> Supporting the 48Gbps bandwidth is the new Ultra High Speed HDMI Cable. The
> cable ensures high-bandwidth dependent features are delivered including
> uncompressed 8K video with HDR.

This is interesting, because I've seen several companies promoting "visually
lossless" compression (which is apparently a euphemism for lossy compression
that the vendor doesn't think you'll notice) to reduce bandwidth requirements
for cabled 8K video transmission. Does this represent some kind of defeat for
them, or were they targeting applications where Ultra High Speed HDMI wasn't
going to be realistic in the first place (e.g. the various systems that
transmit video over UTP cable)?

Also, does anyone know how USB 3.1 SuperSpeed+ cables stack up? Obviously
they're specified for 10Gbps for USB devices, but that's in the context of
USB's requirements for the attached transceivers, so I'm not sure what it
implies about the performance of the cable itself.

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anameaname
At these kinds of speeds, why would we use it for just video? We could make
server interconnects extremely fast.

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ams6110
Modern HPC interconnects are already faster than 48Gb/s

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implr
Those are usually quite expensive. If HDMI requires 48Gb/s capable transceiver
chips to be built into every TV, they will get really cheap very fast. It
might not be a viable solution in the end, but it could work for some
applications.

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paulmd
40 gbps is only Infiniband QDR speeds, you can pick up an adapter for sub-$50
right now.

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notyourwork
And plug it into what?

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paulmd
Your servers?

If you mean switching, you don't need a switch for simply connecting two
computers. Presumably that was the use-case supported by "HDMI-as-network-
layer".

If you watch around, you can get Mellanox Voltaire rack switches for $200 or
less. QDR gear is "obsolete" and often surplused at very attractive prices.
Everyone else has moved onto FDR or EDR speeds.

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MBCook
Could anyone provide a guess as to how “quick frame transport“ works?

As someone who likes games the variable frame rate seems like one of the best
things in here. I wonder if it would be possible to implement in the current
consoles.

I hope the new products announced at CES support this.

~~~
davidjnelson
I read somewhere that the adaptive response rate will work like Nvidia g sync.
A 4K, hdr 75 inch gaming monitor without frame rate hiccups is quite an
exciting prospect!

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MBCook
Right. My understanding is it’s basically the same as G sync or whatever the
AMD name for it is.

I’m kind of curious to see what a game running at say, 50 frames per second,
looks like if the frame pacing is uneven. I imagine it looks worse than 50
frames per second with even frame pacing but better than 50 frames per second
with glitches because you’re supposed to be outputting 60.

~~~
BHSPitMonkey
GSync and AMD Freesync do the same thing, but not in the same way. Freesync is
just a brand name for DisplayPort's Adaptive Framerate specification. GSync is
proprietary, and requires the display manufacturer to add special hardware
into the unit that increases costs a bit.

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qwerty456127
Hasn't the world just agreed on migrating to USB-C for everything?

~~~
simcop2387
USB 3.2 (and currently USB-C from it) doesn't support the 48GBps that HDMI 2.1
and 32GBps that display port 1.4 call for. USB supports a max of 20 GBps at
currently. It's possible you can get more bandwidth using an alternate mode in
the connector, but the spec says you can only guarantee up to the 20GBps over
those modes currently. This means the higher resolutions and higher bitdepths
(10bit, HDR, etc) may not be possible to push over the connector.

This is why Thunderbolt 3 requires special active cables to get the additional
bandwidth by amplifying the signal to help get around the bandwidth limitation
of the connector in a passive configuration.

~~~
Dylan16807
> It's possible you can get more bandwidth using an alternate mode in the
> connector, but the spec says you can only guarantee up to the 20GBps over
> those modes currently.

20Gbps per what? One lane? Two lanes? I haven't heard of this, where can I
find more info?

(If it's actually 20GBps with a capital B then we're nowhere close.)

> This is why Thunderbolt 3 requires special active cables

> the 48GBps that HDMI 2.1 and 32GBps that display port 1.4 call for

This part isn't right.

Thunderbolt 3 can run 40Gbps over short passive cables. And that's
bidirectional. It's the equivalent of 80Gbps for a display cable.

Displayport 1.4, at 8.1Gbps per lane, is actually slower than USB 3.1 Gen 2.

HDMI2.1, at 12Gbps per lane, is slightly faster but still well short of
thunderbolt.

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shmerl
Why would anyone use HDMI instead of DisplayPort? It is cheaper to make?

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mschuster91
Because native plain DisplayPort is only available on HP and some other
Windows laptops (not sure about the state of the desktop GPU market), and it's
_rare_ as input.

The rest of the market - consumer Windows laptops, Apple pre-USB-C-crap-series
laptops, gaming consoles, cable TV boxes, other home theater stuff on source
side, as well as TVs and projectors on the sink side - speaks HDMI only.

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zeelman
> Apple pre-USB-C-crap-series laptops

Totally incorrect. Before USB-C, there was Thunderbolt 1&2, which was over a
Mini-DisplayPort connector.

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sitkack
Display port connector, but only PCIe signaling, no other protocols
implemented.

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DiabloD3
Except for Displayport. Seeing, as you know, half of HN has MBPs they plug
into DP'd desktop monitors, including me.

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sitkack
No, the ports on the Macbook are PCIe + Displayport. The Apple displays are
PCIe only. The parent was specifically talking about Thunderbolt. You aren't
using anything Thunderbolt when you plug into a DP monitor.

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DiabloD3
I've plugged non-Thunderbolt laptops into Apple Cinema displays as well.

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kimburgess
Here's a link to the specification info page and Q&A rather than the press
release:
[https://www.hdmi.org/manufacturer/hdmi_2_1/](https://www.hdmi.org/manufacturer/hdmi_2_1/)

A copy of the presentation from the announcement can also be found here:
[https://www.hdmi.org/download/hdmi_2_1/HDMIForum2.1NovReleas...](https://www.hdmi.org/download/hdmi_2_1/HDMIForum2.1NovReleasePresentation_EN.pdf)

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spilk
can this do 2x 4K @90Hz? e.g. for VR headsets.

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joenathanone
What VR headsets are you using and with what video card? Me thinks we are a
ways away from that.

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dbg31415
Apple, please bring back the HDMI port.

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matt_wulfeck
No thanks. DP over usb-c is way better for all laptops.

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dbg31415
Man, I'm so over dongles.

For the graphics cards that these laptops have... they aren't like super
powerful. I can't, for example, game at 60 FPS on a 4k Monitor on a MacBook
Pro. So the use case for needing more than 60 FPS, or more than a 4k display,
seems more like an edge case to me.

Mostly what I want is to be able to plug into projectors when I'm with a
client so I can share a pitch deck. Instead... I've got this massive USB-C to
VGA / USB dongle, and another for USB-C to HDMI, and yet another for USB-C to
Thunderbolt for my work monitor. Anywhere I go I've gotta lug around a laptop
bag now, and it's full of dongles.

The OLD 15" MBPs were perfect. Good mix of ubiquitous ports, and Apple's
proprietary Thunderbolt ports. I have yet to find anything other than dongles
that use USB-C. Just like I have yet to find anything other than Apple
Thunderbolt Displays that actually use Thunderbolt.

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ComputerGuru
I was in the same boat when I was on my rMBP with its thunderbolt ports but
now with usb-c, I just carry this one:
[https://www.amazon.com/dp/B01KV5332A/ref=cm_sw_r_cp_api_onqj...](https://www.amazon.com/dp/B01KV5332A/ref=cm_sw_r_cp_api_onqjAbYAMAREE)

