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.
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?
#42I 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".
Even a $1 micro should be able to handle a few bits of resolution information in less than a millisecond. This can't be it.
There's a lot going through between your OS and the monitor when you plug a display, really. HDMI and DP are two-way protocols.
Expecting everything instant-on is naif.
Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?
#43Earlier quoted context omitted.
Monitors don’t request anything. The monitor has to do a basic handshaking/negotiation before it even knows what sort of video stream to expect
Ah. And we couldn't stick... What, 4 ints of metadata in the video steam (width, height, depth, frame rate)? Not like we don't have the bandwidth. I can believe that, but it's disappointing that nobody bothered.
Historically speaking bad things happen when you hand a display something it can’t handle - including not being able to see the settings dialog to fix it.
Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?
#44This 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.
Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?
#45HDMI 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.
Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?
#46Earlier quoted context omitted.
It’s ok, I can wait 17ms for the next frame.
With basic analog you could set it up in a way where you would just wait for the next frame (or don't even wait that long), but with the new digital stuff there's bootstrapping/handshaking - whatever you want to call it. It's not so simple anymore.
What could they possibly be doing that takes 4 seconds? That's ~4,000,000,000 instructions on a typical embedded processor.
It's much more likely that the handshaking was implemented by an incompetent organization that doesn't care about quality.
Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?
#47Earlier quoted context omitted.
Even a $1 micro should be able to handle a few bits of resolution information in less than a millisecond. This can't be it.
There's a lot going through between your OS and the monitor when you plug a display, really. HDMI and DP are two-way protocols. Expecting everything instant-on is naif.
Then there must be something badly wrong with the protocol and/or implementations. Negotiating a few bits over a high-quality cable link should be instantaneous.
Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?
#48Unrelated: OP, how do you like the U2723QE? Been trying to decide on pulling the trigger on two of them recently.
I have one, it's a really nice monitor, sadly there is a small "but". Sometimes, it starts flickering. I'm not completely sure what causes it, but closing the nearest Eletron app will normally fix it.
Yesterday my kid wanted to see a video of volcanos on YouTube, followed a really bright picture of My Little Ponys, the monitor managed to start flickering and retain a shadow image of the little ponies, even as I switched between laptops and power cycled the monitor. This only happens on USB-C input, but seeing as the monitor have an Ethernet adaptor and works as a USB hub, USB-C is pretty much the reason I got it.
Notes: It happens really rarely, and exclusively with the M1 MacBook Air. It might be a firmware update away from being fixed. Also Dells has an excellent return policy.
Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?
#49Earlier quoted context omitted.
There's a lot going through between your OS and the monitor when you plug a display, really. HDMI and DP are two-way protocols. Expecting everything instant-on is naif.
Then there must be something badly wrong with the protocol and/or implementations. Negotiating a few bits over a high-quality cable link should be instantaneous.
There could be, but there are (at least) three parties involved in whatever's causing the slow monitor response. I find it irritating even without a switch, just plugging in my external monitor should not take what seems like thirty seconds to actually turn on.
But in reality, you've got whatever tiny micro is inside the monitor, talking to whatever's on the graphics card, in turn talking to display drivers and who-knows-what-else on the PC side.
Slightly related to this, in some ways, is things like wifi connection. I have an ESP8226 that I've built a clock around. That thing will connect to the wifi, negotiate security, contact a time server, probably within one second. None of that is down to my ingenuity, it's literally how it works out of the box.
So the problem may just as much be on the OS side, rather than the monitor and the E-DID protocol.
Re: Ask HN: Can you recommend an “instant-switch” Monitor? Does one exist?
#50Unrelated: OP, how do you like the U2723QE? Been trying to decide on pulling the trigger on two of them recently.
I've got a U3223QE which is the same just larger. The screen itself looks really nice, its bright, no complaints there. The stand is pretty good, reasonably tidy. My only complaint is that when it said USB-C hub I expected it to have USB-C ports for peripherals and it doesn't, only USB-A ports. My older LG has USB-C ports, so I know its possible. It's annoying because as more and more stuff switches to USB-C the only place to plug those in is the laptop itself, which means messing around with too many cables.