Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

news.ycombinator.com

Post reply on HN
Print view View original

161–170 of 185 posts

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

#161

Post by magixx »

Terretta wrote: post #88

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…

Given the $550 price of these, did you ever get to trail one of the cheaper ~$100 options for an 8k 4x2 matrix switcher? I had been looking at one so that I can retain HDR with windows when duplicating displays and the cheaper ones seem to provide similar functionality.

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

#162

Post by cptcobalt »

Terretta wrote: post #88

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…

Dang, this seems like it might actually resolve some of my HDMI issues for my gaming computer display output.

I tend to play games with my projector on mirroring computer output (for things like watching people play VR games socially), and I use a "cheaper" HDMI switcher for the projector to achieve this (it's one of the better ones you can buy in Amazon)—but this breaks the 4K60 HDR output for some games if I'm mirroring displays.

This might switcher might be fully featured enough that my computer won't balk at it.

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

#163

Post by atoav »

bombcar wrote: post #132
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…

Note that an expensive HDMI switcher is different from a cheap dongle goblin from Amazon. Try the cheap one first but if you really need instant switching you’re looking at a professional AV device. http://decimator.com/ Has some really good shit including (accidental) hdmi copy protection removal.

I am a media technician myself and the odd thing is that I have found no real corellation between price and capabilities when it comes to HDMI switchers, splitters and grabbers.

Sometimes the 400 Euro grabber works sometimes the 30 Euro one works. The expensive ones are surely more rugged tho.

I suspect all most manufacturers do is build a decice around some existing HDMI IC and if your stuff is supported by that IC and they didn't cut a ton of corners it works. Maybe you need the 4000 Euro price class to run it all, I never tried.

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

#164

Post by Grimm665 »

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…

> A cheap hack would also be to connect your second source to the first using a HDMI Grabber (basically a HDMI-source-to-USB-webcam-converter) and open a fullscreen window displaying that. Then you could e.g. switch by switching virtual desktops.

Is this something you've tried before and could go into more detail about? I've got an HDMI grabber for using a DSLR as a webcam, but never thought to output the display of one of my computers to another. This would solve a lot of issues regarding switching between work and personal laptops.

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

#165

Post by Moru »

bitwize wrote: post #135
reaperducer wrote: post #128

Earlier quoted context omitted.

On the Atari and Amiga, the horizontal/vertical scan rates are constant I can't speak to the Atari, but my memory is that this is not true of the Amiga. The Amiga could do this amazing thing where it would display multiple resolutions on a monitor at the same time, divided horizontally. Analog was flexible that way. An Amiga could even display two different resolutions from two different sources on the same monitor a…

Yes, because the scan frequency didn't change -- that's what I'm trying to say (my terminology may have been a bit off). The timings of the horizontal and vertical sweep of the beam were constant; upon mode change the CRTC changed how scanout occurred, doubling the width or height of pixels in lower resolution mode but it didn't change the scan frequency , allowing the mode change to occur while the beam kept moving…

The Amiga could do a lot more than the Atari with the gfx chip. The Atari had three modes, 320x200, 640x200 and 640x400 so two horizontal and two vertical resolutions. It also can change frequency between 50 and 60 Hz but that wasn't instant, it took a couple of frames to stabilize. This I think you could use to get borderless screens with even higher resolution but I've forgotten exactly how it worked.

For the highest resolution you needed a better monitor though so I didn't have much experience with that one. The Atari Falcon also had more resolutions with instant switch but my memory is getting quite fuzzy there :-)

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

#166

Post by orbital-decay »

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…

> HDMI Switching like that takes long because there is a EDID negotiation going on between the minitor and the input devices.

Why does the negotiation take so long, though? There doesn't intuitively seem to be a lot of information.

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

#167

Post by 83 »

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…

Top comment leaves out HDCP entirely as well which I would wager is where a lot of people experience delay. If you want to learn more about it search for the edid hotplug detection. Once that gets negotiated it is followed by the hdcp handshake. Keep in mind while reading up on this the industry terms for devices are "source" and "sync". Video goes from source to sync.

The hdcp handshake is a particularly bad mess which most manufacturers don't implement well due to a very confusing spec. My experience has been some devices start showing video right away and kill it if hdcp handshake fails, while other devices don't show video until hdcp handshake succeeds. Behavior is quite hardware dependent.

The commercial vendors like Extron (crosspoint switchers) and Crestron (digitalmedia switchers) have this figured out pretty well where switching is almost instant so it's definitely possible. I think Crestron has some technical papers out there that discuss the challenges involved.

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

#168

Post by bombcar »

atoav wrote: post #163
bombcar wrote: post #132

Earlier quoted context omitted.

Note that an expensive HDMI switcher is different from a cheap dongle goblin from Amazon. Try the cheap one first but if you really need instant switching you’re looking at a professional AV device. http://decimator.com/ Has some really good shit including (accidental) hdmi copy protection removal.

I am a media technician myself and the odd thing is that I have found no real corellation between price and capabilities when it comes to HDMI switchers, splitters and grabbers. Sometimes the 400 Euro grabber works sometimes the 30 Euro one works. The expensive ones are surely more rugged tho. I suspect all most manufacturers do is build a decice around some existing HDMI IC and if your stuff is supported by that IC…

That’s what I’ve seen. Some super expensive gear works often but having various devices with various chipsets seems the way to go.

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

#169

Post by naikrovek »

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.

> You could switch channels as fast as you could press the button.

Yep, and everything was exactly the same video format, and all TVs had the same capabilities.

The slowness was present on VGA monitors as well, if you recall.

Slow switching is a tradeoff worth having, given that it allows me to have any number of digital resolutions and color depths available to me.

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

#170

Post by kimburgess »

mort96 wrote: post #116
kimburgess wrote: post #51

Not on a monitor (that I'm aware of), but it is a major feature of signal distribution equipment for installed AV and broadcast. A large part of the delay that you are seeing is from EDID negotiation and HDCP. This happens of the 100kbit/s DDC channel and requires a bit of back and forth. On the above systems this is pre-negotiated so that switching can take place across a single frame. A lot of that equipment is lik…

100kbit/second is still blazing fast for communication which ought to be on the order of a hundred bytes... 4 seconds at 100kbit/s is 50kB. Why does it have to be so chatty?

When the input is first selected here's will be a hot plug detect, EDID request and an EDID response. That response can be up to 32kB so anywhere up to ~2 seconds depending on how many extension blocks are in use by the display. Here's a nice breakdown on more of what happens there: https://research.nccgroup.com/wp-content/uploads/2020/07/hdm....

When a suitable set of image parameters have been agreed HDCP (may) then step in to ruin your day. Again a nice walkthrough of that is available here: https://blog.cryptographyengineering.com/2012/08/27/reposted....

As other commenters have correctly noted, there's definite room for improvement. One thing to remember though is this involves hardware that can be in operation for the order of decades so there's a lot of cruft that accretes in order to maintain compatibility. Frankly it's mildly impressive that for the most part all the above happens in silence and continues to (mostly) work.

Post reply on HN