I have a passive A-B-C-D VGA switch. Using this with 2 computers going to a projector makes the computers resync when it's switched (they also aren't holding the settings for it so I end up with wrong resolutions). Obviously that's not desired. I'm trying to figure out a way to trick the computers so that they continuously output (the correctly scaled image which would be set before show). Anyone know how to do this? Other than 2 splitters between the switch and computer with out #2 going to a monitor/spare projector/whatever.
Video Switching
- Thread starterLavaASU
- Start date
There are cheaper alternatives, but you may end up with what you pay for. It is possible that your graphics car will allow you to set an output resolution and not be set by the projector. That will be in the advanced settings of the graphics card.
Unless you use a seamless switcher then there will be a 'resync' every time you switch. However, that should not affect the resolution of the computers.
If that is a result of an EDID issue then assuming both computers support that resolution, scan rate, etc., the projector EDID should be forcing both computers to the projector's preferred settings. Perhaps the issue is what you define as "the correctly scaled image" on the computer, is that something other than the native/preferred resolution of the projector? And if so, is there a reason for that?
In that case we were forcing both of the projectors to take 1024x768 instead of native (one that was native, other 800 x 600) because we were using 2 and they were different native resolutions. However we tested with just one outputting native and we were still getting a bunch of flickering between image and a blue screen and about 25% of the time it ended up stopping on something other than native!
I have a video card that will not hold a resolution when the device is switched away from it. I use the DVI Parrot (which I didn't mention before since you were looking for VGA) to manage that output. Most video cards which I have used in the past will hold that information if you have the display powered on prior to booting the computer, but nothing I have found will do that for this particular card. Since you are using a passive switch, it is the same as constantly unplugging the extended display each time and the video card is always looking for a new device as well as the projector re-syncing (the flicking between blue screen and image). If that sync somewhat fails and does not get the proper EDID, it will generally default to the lowest resolution. With the 800x600 projector, you should be able to get by without the emulator.
Both projectors? If you have two projectors connected with different preferred resolutions then that could be an issue unless the switch or a related DA or something is managing the EDID.
There are some free EDID readers out there such as Extron EDID Management - EDID Manager®. That may help you see what EDID data your computer is reading and storing.
Do you know if it is the computer output or the projector input that is giving the flickering and blue screen? With a simple 'crash' style switcher the projector typically will lose sync when you switch betwen sources and thus have to resync after the switch.
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