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Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?

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Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?

#81

Post by dmurray »

pontifier wrote: post #44

This is one thing I really miss about analog tv. You could switch channels as fast as you could press the button. Everything now is so slow.

I assume this is for a different reason - buffering and stream compression, you have to wait for a key frame before your TV can display anything.

Similar root cause though - technology becomes available that makes the steady state performance much better in return for some setup costs, the setup costs are worth paying in almost all applications so it's an obvious choice to go with the new technology but still annoying when you encounter its drawbacks.

Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?

#82

Post by TacticalCoder »

bitwize wrote: post #53

OK, remember when modems were like EEEEEEEkRrRrRrRrRrRrRbaBONGbaBONG.... That was handshaking, and it was how modems figured out which speeds and protocols each other supported so they could figure out how fast to transfer data and how to encode it. Monitors are kind of the same. There's handshaking that goes on each time you connect a monitor to a video source. Like (and I'm totally making this up): - Hi, I'm an AMD…

But why does it take a couple of seconds? I can send a ping thousands of kilometers away and get the ICMP reply in 100 ms or something. I can ping my router in less than a millisecond and my router is further away than my computer.

Why does this whole negociation take seconds and not milliseconds?

Or my car: it's full of electronics. Chips and code everywhere. Even my pedals, which used to be cables decades ago, are now fly-by-wire. It's chips and code everywhere.

Yet feedback is instant.

Now I understand a monitor is not the same as ethernet and is not the same as a car but... Seconds?

Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?

#83

Post by fps_doug »

pontifier wrote: post #44

This is one thing I really miss about analog tv. You could switch channels as fast as you could press the button. Everything now is so slow.

This is one of the things on my TODO-list for when I stumble upon a way to have infinite amounts of time:

Learn "FPGA 'n stuff" and build my own display controller. Like many people here, I don't understand why this takes so much bloody time. Not just the input switching, but also switching resolution or refresh rate on the same input. So either I'd have an a-ha moment and see why it's not possible (more likely outcome), or well, it'll just work and I can write a cool hackaday post.

The EDID explanation given in the comment currently at the top doesn't make too much sense: Even if the display is off and not in some super hardcore energy saving mode, EDID works, i.e. your computer can query the EDID data from the screen and know what its preferred resolution is, etc. Likewise, even if your display is switched to HDMI-1, a machine connected to HDMI-2 can already be outputting 1080p60 to it, so why does switching inputs take more than a few milliseconds?

Afaik (and I only have very rough knowledge here), there is no side-channel in HDMI/DVI that tells the display what mode it's actually receiving, so the display has to look at the signal and make sense of it. So you have to put some brains in it. But that can hardly take several seconds, i.e. hundreds of frames? Maybe two or three frames! I could see this being a cost cutting measure, maybe doing the dumb implementation that takes seconds instead of milliseconds saves you a cent or two per device.

Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?

#84

Post by wruza »

int0x2e wrote: post #69
neilalexander wrote: post #62

Earlier quoted context omitted.

> Monitors are kind of the same. There's handshaking that goes on each time you connect a monitor to a video source. If the connector is high bandwidth enough to send hundreds of thousands of pixels 60 times a second, how can it possibly be so slow to send a few bytes of handshake or EDID data? Handshakes should be happening nearly instantly. You can complete opening a TCP connection to the other side of the world in…

There's a major difference between the data-plane (the lanes where frames go from the signal source to the display) and the control-plane (the command and control channel that is bidirectional and used to discover a peer and negotiate settings). The former is indeed very high speed, in the order of gigabits per second (up to 48gbps in later iterations), whereas the latter can seem ancient in comparison - 500bps to 11…

Example EDID: https://edid.tv/edid/752/ (one can also go through a github link at the bottom)

Most EDIDs are 256 bytes in that repo. At 500bps it may take seconds to transmit, but 115.2kbps (14kbytes/s) is enough to do it in an instant.

As usual, the issue is probably not a bus speed or a chip cost itself, but a crappy legacy timeout-based negotiation process which nobody touched or restandardized since it was slapped together. You can’t just autoupdate all compatible hardware in the world and move on.

My blind economical guess is that one couldn’t even find controllers today which are slow enough to DDC back and forth in seconds, because the package/assembly probably takes 95% of the cost anyway. Please correct me on that, I’m curious.

Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?

#85

Post by eqvinox »

snthd wrote: post #71
atoav wrote: post #45

HDMI Switching like that takes long because there is a EDID negotiation going on between the minitor and the input devices. If you want to switch fast and often your best bet is getting an HDMI switcher that is basically always connected to the monitor and both sources and then toggles between the two. Beware of the supported resolutions and framerates. A cheap hack would also be to connect your second source to the…

What if you modify the cables to remove the DDC wire? Can no EDID negotiation be faster?

> Can no EDID negotiation be faster?

No, at this point removing EDID will simply get the display not detected at all. It used to be optional in the times of VGA, where you could just drive out 640x480 "blind", but there's too much stuff in there these days.

Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?

#86

Post by prmoustache »

You might be able to do that with a master computer running OBS in studio mode, an HDMI capture car for each source you want to connect, projecting the scene to your Monitor all the time and some hardware device with buttons to switch scene.

But this is kind of a hack and you would possibly have undesired latency, especially noticeable when typing fast and moving the mouse.

Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?

#87

Post by joahua »

fps_doug wrote: post #83
pontifier wrote: post #44

This is one thing I really miss about analog tv. You could switch channels as fast as you could press the button. Everything now is so slow.

This is one of the things on my TODO-list for when I stumble upon a way to have infinite amounts of time: Learn "FPGA 'n stuff" and build my own display controller. Like many people here, I don't understand why this takes so much bloody time. Not just the input switching, but also switching resolution or refresh rate on the same input. So either I'd have an a-ha moment and see why it's not possible (more likely outco…

Or, perhaps, weird regulatory/big customer energy saving reasons - “TCO” stickers and whatnot imply some kind of standard measurement, can imagine a “wake from sleep on source change” benchmark driving odd behaviours.

Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?

#88

Post by Terretta »

Recently (last few months) I've been testing HD Fury VRRoom, and am happy with it, as it allows switching instantly regardless of monitor, by having negotiation already set up:

https://hdfury.com/product/8k-vrroom-40gbps/

It maintains a live connection to each of 4 x HDMI inputs, 2 x HDMI outputs (mirrored or matrixed), and 1 x eARC audio output, and can switch between them "instantly" as you ask. You can switch with a button at your desk, or via API.

I selected this model because it supports (a) up to 8K and we use 5K monitors, both full 5K and ultrawide 5K, and (b) variable refresh rate (VRR) at 4K@120hz for gaming.

In a teleconference room with e.g. a big on the wall and a small screen on the table showing same or different sources, this lets you have multiple input sources (e.g., teleconf system, laptop, game system, and OTT TV source) that 'just work' without users having to know how to make it work.

The feature list for video includes:

- Unlock true VRR/FRL on Samsung Q90/QN900/QN95 and similar models

- Up to 8K60 444/RGB 12-bit via DSC at 96Gbps

- World First 40Gbps Upscaler, Splitter, Switcher with full audio extraction for VRR and any signals

- Play Xbox 1X games at 4K120 Dolby Vision on LG C9, BX & SONY HDMI 2.1 TV

- Work from ANY HDMI source to ANY HDMI, ARC or eARC sound system

- HDMI 2.1 Full Audio/Video passthrough up to FRL5: 40Gbps/1200MHz

- Upscale FRL5 and ANY signals 2K>4K, 4K>8K and 2K>8K up to 120Hz (no upscale for VRR/1080i/720p/480i-p)

- Downscale ANY FRL0/TMDS signals 8K>4K, 4K>2K or 8K>2K up to 120Hz (no downscale for FRL5/VRR tbd)

- Add or remove any input from the CEC network at any time via webserver, APP, IR/IP or RS232

And for audio, it solves getting eARC signal to amps or soundbars that can support Atmos when the monitor or TV doesn't support it:

- Full Audio from ANY HDMI source (including VRR signal) to ANY HDMI, ARC or eARC sound system

- Full Audio up to Atmos/TrueHD from any HDMI source to SONOS Arc/Beam2 or any eARC sound system

- Solve SONOS Arc/Beam2 + other lip sync issue when using external HDMI sources connected to eARC TV

If you get one and find yourself needing support, join their Discord server.

Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?

#89

Post by kimburgess »

vermilingua wrote: post #68
chmod775 wrote: post #16

You'll need a fancy KVM switch that does more than merely acting much like a physical switch would. Something like this should probably work: https://www.rextron.com/product-4K-2-Port-Full-Frame-PBP-KVM... Edit: The one above is merely the first one I found, not a recommendation. Be aware that such things may incur extra latency, since it's not just passing signals through, but rather processing them and repackaging…

As an aside: does anyone know the deal with Rextron, Extron, and Crestron? What’s going on with the names there?

Extron and Crestron are both major vendors within the audiovisual industry. Both make (mostly) extremely solid products.

Rextron is not a company or set of devices I've ever encountered. From a quick look at their site they look to be an OEM/ODM provider though so would hazard a guess they may have taken some 'inspiration' from either of the above orgs.

Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?

#90

Post by Handprint4469 »

jemmyw wrote: post #74
Handprint4469 wrote: post #64

Earlier quoted context omitted.

Just in case you missed it, the U3223QE does have one USB-C port for peripherals. See [0], bottom right of the image. [0] https://i.dell.com/is/image/DellContent/content/dam/ss2/prod...

That's the USB-C upstream port for if you connect PC-2 via HDMI and PC-1 is connected to the USB-C display port.

I meant further to the bottom-right. Here: https://imgur.com/00KDqpq
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