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

by kappuchino on 12/19/22, 4:41 AM with 178 comments

• by atoav on 12/19/22, 7:49 AM

  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 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.

  Another post recommended rhe Blackmagic Atem, this should also work.

• by Moru on 12/19/22, 6:21 AM

  This has been annoying me since I first tried a PC after using Atari computers since they were a thing. No matter what monitor I use, it will take for ever to switch input port or just a simple change of resolution. I was used to be able to switch resolution several times per frame, you could make a game with low resolution and color on the upper 3/4 of the screen and have the stats in higher resolution 4 color mode on the lower 1/4 of the screen without any sort of delay in the signal, you just set an interrupt on every scanline and if the monitor was painting the 300'th scanline, you witch mode and suddenly it's doing double resolution for the rest of the frame. Then switch back on the Vertical Blanc Interrupt at the start of the frame paint.

  I was quite surprised when the brand new PC needed 2-3 seconds just to switch resolution. And we are still there after 30-odd years? A KVM switch with analog signal was just the same, still long time to switch between signals. I'm using a remote control software to the local computers so I don't have to wait between every switch. With the added bonus that I can copy/paste between the computers without having to think.

• by tcbyrd on 12/19/22, 7:42 AM

  Closest you’ll get is something like a Blackmagic ATEM switcher, using “Program” as the output. Then you can map a software key to swap it out in a single frame. As discussed in another thread, the computer has to be sending the display signal to some device that is seen as a display, and that switcher keeps the video from both PCs buffering at 60 or 30 fps. To the computer it can’t know the display switched and the display can’t handle two simultaneous streams, so you have a device in the middle that bridges that. Down side is depending on the quality of the switcher you might get 1-2 frames of lag because it’s optimizing for frame accurate sync to ensure the least possible “flicker” when the source is switched.

• by pontifier on 12/19/22, 7:47 AM

  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.

• by whywhywhywhy on 12/19/22, 2:30 PM

  100% convinced we wouldn’t live in a world with trash like this if just a few more people would say “it’s very slow, can you make it faster? No I don’t care what the excuse for it being slow is I still think it can be faster, currently it feels cheap and awful”

  Weird how you say that then the thing that was “that’s just the way it is” is often completely solved in the next day or two.

• by Terretta on 12/19/22, 10:35 AM

  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.

• by kimburgess on 12/19/22, 8:41 AM

  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 likely price prohibitive for desktop use, but you may be able to reduce the time a little with sidestepping that process either in your machine setup or with an external bit of lower cost hardware like and EDID emulator (e.g. https://www.extron.com/product/edid101h4kplus).

• by sandworm101 on 12/19/22, 11:37 AM

  Your answer wont be found in monitors. You need a media switch, a good one like thise used in the enteraimment industry for broadcast-quality transitions between inputs. Alternatively, look into streamer-quality "media switches" used by streamers with multiple camera rigs.

  https://restream.io/blog/best-video-switchers/

• by chmod775 on 12/19/22, 6:43 AM

  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 them.

• by bitwize on 12/19/22, 8:48 AM

  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 video card.

  - Hi, I'm an LG monitor.

  - You're a monitor? Great! I have some data I'd like to display. What resolutions, refresh rates, and color depths do you support?

  - Well, I support 1920x1080x24bpp@60Hz, and 1600x900x24bpp@70Hz, and...

  - Cool! I'd like to display at 1920x1200x24bpp@60Hz, please.

  - Sure thing, hang about while I get that set up.

  [Monitor CPU sets up whatever framebuffers, scalers, etc. are necessary to display at 1920x1200x24bpp@60Hz]

  - Right then. Ready for your first frame.

  - All right, first frame incoming...

  Only then will you get your display. This can take a couple seconds.

• by jtwaleson on 12/19/22, 6:11 AM

  Ugh yes, this should be benchmarked! I’m currently on a 34” widescreen Philips monitor and it takes about 10 seconds to switch, it annoys me majorly every time I do it. Just starting the overlay UI seems to take 5 seconds.

• by lcedp on 12/19/22, 12:39 PM

  I think HDMI EDID Emulator can be useful. For instance, https://smile.amazon.co.uk/gp/product/B095JXDM84/ref=ppx_yo_...

  In my (very poor) understanding, it 'caches' the information about monitor capabilities. I used it to prevent my laptop from rearranging windows when my monitor goes to energy saving mode.

• by foresto on 12/19/22, 10:46 AM

  This delay also often happens when I switch between linux virtual consoles (Control+Alt+F7/F8), despite both of them using exactly the same X display settings.

  Not always, though. The switch sometimes happens instantly. (At least, it has been this way since I replaced my Nvidia card with an AMD. I don't recall whether the Nvidia ever switched instantly.)

  I wish I knew what conditions make it instant, so I could try to make it happen consistently.

• by modeless on 12/19/22, 8:42 AM

  I bought one of the first GSync monitors many years ago (ASUS PG278Q ROG Swift) and it goes from sleep to displaying an image in just a fraction of a second. It's totally amazing, way faster than any other monitor I've ever seen, including newer GSync monitors. It only has one single input port though. I've never tried hooking it to a KVM, but I bet it would switch super fast.

  Maybe try one of the first gen (2014) GSync monitors along with a DisplayPort KVM, if that can work for you. It's my understanding that the first gen GSync monitors all used the same monitor driver board that Nvidia made, so they probably behave similarly.

  Honestly I didn't know how much I needed fast wakeup until I had it. It's a way better feature than GSync, yet monitor and TV reviewers generally ignore it completely. There are probably newer monitors with fast wakeup but it's impossible to know without testing. My TV takes like 8 seconds to even turn on its backlight and it's just ridiculous.

• by evadne on 12/19/22, 11:59 AM

  You need a video matrix such as:

  https://www.lindy.co.uk/audio-video-c2/matrix-switches-split...

• by EspadaV9 on 12/19/22, 9:06 AM

  There are applications that seem to switch faster than using the OSD, like [0], however, they need an OS running to use.

  0: https://codeberg.org/Okxa/qddcswitch

• by klntsky on 12/19/22, 9:42 AM

  > i.e. due power save mode

  This is your problem, isn't it? I never use power save mode and have no problems with these delays.

• by gfd on 12/19/22, 9:49 AM

  Gigabyte gaming monitors come with a physical kvm button: https://www.gigabyte.com/Monitor/M32U

• by alanbernstein on 12/19/22, 2:03 PM

  I appreciate this question, I would also appreciate a solution, and the explanation of why it happens is interesting.

  However, what I really want is just to be able to switch the input via command line. I know that there is a protocol that supposedly allows this (ddc?), But it seems that support for it is not standardized. This means the feature I want can't be found in the product specs.

  So my question: what's a monitor I can buy that will allow me to switch inputs by command line? (Ideally 4k)

• by teekert on 12/19/22, 7:13 AM

  Yeah would be nice to be able to alt-tab between monitors (or I should say: sources). I never understood why it is so slow. I have a somewhat older Samsung TV and I even have to cycle all the inputs (8?) to arrive a the correct one and it takes 1-3 sec on every input before I can get to the next. Absolutely maddening. But I guess manufacturers were too busy making 3D a thing and then "curved". Maybe they can now decide to fix some basics?

• by alin23 on 12/19/22, 6:30 AM

  My old LG 27UD88 switches in about 1 second when pressing the relevant hotkey in Lunar (https://lunar.fyi/)

  It’s not instant but input switching through DDC is the fastest possible method.

  That’s because the input that will be switched to is already connected and receiving video in the background, skipping the HDMI/DP protocol handshake and going straight into rendering the new video on the screen.

• by yourapostasy on 12/20/22, 7:11 AM

  Take a look at ConnectPro video emulators [1]. Mentioned [2] and praised [3] here on HN before, but there are limits on their KVM's [4] to watch out for so just a caution to don't hastily ascribe the same performance from their emulators to their KVM's if you're also messing around with switching configurations.

  [1] https://connectpro.com/collections/video-emulators

  [2] https://news.ycombinator.com/item?id=24362388

  [3] https://news.ycombinator.com/item?id=24362975

  [4] https://news.ycombinator.com/item?id=26906688

• by brysonreece on 12/19/22, 5:23 AM

  Unrelated: OP, how do you like the U2723QE? Been trying to decide on pulling the trigger on two of them recently.

• by adastra22 on 12/19/22, 9:51 AM

  > The monitor is on a switched off source i.e. due power save mode

  Do you want your cake, or you do want to eat it too?

• by 3np on 12/19/22, 8:49 AM

  Tangentially related: I find many monitors that look great on paper are a real annoyance when it comes to controls, be it brightness/contrast or input switching, making those 4s irrelevant in comparison.

  Between recent models of Acer/Dell/Eizo/LG, I found Eizos to pose the least friction so far, with the LG (may be model-specific) a surprising worst. Reply to this comment with your anecdotes!

  EDIT: To address the OP: Switching from an offline source to an active one is def smoother than you describe on my Eizo FlexScan EV series - I estimate it to <2s. The input switching is bearable enough that using the PbyP (two input sources split) is something I occasionally do, whereas with Dells it was just annoying enough to make me not bother.

• by hunter2_ on 12/19/22, 6:40 AM

  If you can get HDMI from all your sources, something like this might work for 1080p: https://www.bhphotovideo.com/c/product/1507214-REG/blackmagi...

  More options, like if you need higher res: https://www.bhphotovideo.com/c/buy/Live-Switcher/ci/2865

• by c7b on 12/19/22, 1:10 PM

  I like using KVM switches for connecting multiple sources - if you are using multiple laptops/PCs, it has the benefit that you can use the same keyboard/mouse for all of them.

• by apelapan on 12/19/22, 7:14 AM

  Slow screens, they annoy me so much too!

  Somewhat on this topic, I wish one could compare motherboards by the time-to-boot delay.

  If reviewers start benchmarking something, manufacturers will optimize for it eventually.

• by magixx on 12/19/22, 5:08 PM

  If you're looking for a monitor with responsive software avoid the Gigabyte M28U like the plague. Sure it's got 4k 144hz and when that works it's visually great. However, monitor sleep/wake or any other funcitonaly such as switching inputs had been a nightmare to the point that the most effective way to switch inputs quickly is to turn it off and on. At this point I'm really considering selling it for something with better software.

• by jwr on 12/19/22, 9:00 AM

  I'm spending anywhere from 10 to 30 seconds every time I want to turn my monitor on. It's a game of fiddling with the buttons, trying to get it to wake up faster.

  As an added bonus, the built-in firmware is terrible, and presents a "quick-switch" list of inputs which is different from the "normal" list of inputs, because… well, I don't know, just to make customers miserable, I guess.

• by prmoustache on 12/19/22, 10:27 AM

  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.

• by spants on 12/19/22, 9:27 AM

  I was annoyed by this too. My solution was to buy a 49" samsung monitor and have either 50:50 or 1/3:2/3 split on the screen so I can see both at once. If I only want one active I can change the source but this has the flicker/delay as noted. I run Barrier software on both to move one keyboard and mouse between the screens.

• by dizhn on 12/19/22, 5:07 PM

  I am using the setup from this blog as a software kvm solution and would love for it to be faster but it is manageable with my HP monitor.

  Link: https://xpufx.com/posts/hundred-percent-software-kvm-switch/

• by voxelghost on 12/19/22, 7:40 AM

  I don't know the specifics of your monitor. But you say the source is in power-save mode? I think then it has also signaled to the monitor to enter power-save mode.

  So if your monitor supports it, turn off energy-saving mode settings might fix the issue.

  It might also be less annoying to wait 4 seconds, if you think of it as helping to save the planet ;-)

• by jenscow on 12/19/22, 11:31 AM

  Maybe solving your problem in other ways:

  0: I use `ddcutil` (on Linux), it takes about 2 seconds for the switch: `ddcutil -b $bus setvcp 0x60 $source`

  1: Use something like NoMachine or VLC - would probably cause more problems if you've got devices that go into power-save mode

  2: Ensuring that your devices are outputting the exact same mode may decrease the time.

• by leriksen on 12/20/22, 4:17 AM

  I have a Samsung S34J55x, and a DisplayPort 4 port KVM from Lindy. I have 3 laptops connected, all different makes (lenovo, dell, ms), and they generally take 1-2 sec to switch between machines. Maybe the key is the video interface eg HDMI vs DVI vs DP, be an interesting experiment.

• by brokenmachine on 12/19/22, 11:30 PM

  I have an OLED monitor and between being completely black with no input, and taking a long time to switch inputs, I'm often not sure if it's actually turned on or not.

• by Temporary_31337 on 12/19/22, 1:04 PM

  Maybe get a dedicated display for your devices or just get a huge 4K or 5k display with PIP mode or vnc/remote into the machines so that the switch is software based.

• by trap_goes_hot on 12/19/22, 6:53 AM

  If I were you I'd use a hardware KVM device that goes to a single input source on the monitor and keep the monitor always-on with a black screen saver to prevent burn-in.

  I was in a similar situation when I wanted a easy way to switch between speakers/headphone at any time without messing with settings or apps. I ended up using a physical switch. https://www.amazon.com/gp/product/B008BMLXAU/

• by whalesalad on 12/19/22, 5:09 AM

  An external KVM switch might help but a lot of monitors suffer from this issue u fortunately and I don’t think anyone has benchmarked this

• by mschuster91 on 12/19/22, 1:19 PM

  If you got the cash, get a Blackmagic Atem Mini video mixer and an appropriate amount of x-to-HDMI dongles.

• by GianFabien on 12/19/22, 6:50 AM

  I suspect there is a tiny CPU inside the monitor that looks at a variety of things before deciding how to decode the signal and present it. As @alin23 notes, DDC protocol is also handled. Obviously the manufacturers are using the lowest cost BOM that they can get away with and that would probably mean a $1 microprocessor in charge of the "smarts".

• by VinLucero on 12/19/22, 7:20 AM

  I wish this existed. Samsung Odyssey G7 has the same issue.

• by stevebmark on 12/19/22, 6:21 AM

  No, nothing like that exists, and no KVM exists that does instant switching.

• by blacklite on 12/19/22, 6:20 AM

  There are hardware limitations that make what you're asking for impossible.

  Use software solutions if you actually need instant switch. But you probably don't.

• by lofaszvanitt on 12/19/22, 7:00 AM

  There are multiple input (5xHDMI) same output (1x HDMI) switches on the net, which feeds one input of the monitor and you can change the source on the adapter with a round robin button. It's almost instant. Another cool feature is whenever a new input source is detected it automatically feeds that to your monitor. I haven't seen the configuration you need, but if you can use adapters to convert each source to HDMI, it works like a charm. It's called an HDMI switch.