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Video splitter: different images on different screens - SOLVED!!

Last response: in Graphics & Displays
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September 30, 2009 6:38:16 AM

I need to find a “video splitter” with a twist. Literally.

I have a Belkin 4-port dual-head (vga only) KVM, and attached to it are three workstations. Each workstation has a dual-head video card. Some have VGA/DVI pairs, others have two DVI ports.

Since LCD monitors that run at 1600x1200 resolution are so expensive (widescreen is all the rage these days -- and I ***hate*** widescreen monitors!!) I am looking to run four monitors that each have a 1280x960 resolution. That way, I can pick them up on the cheap, but have a combined (total) resolution of 2560x1920 (cube arrangement). This is to maintain the 4:3 ratio that I so love, but provide me with four separate screens.

My problem is that I only have a dual-head KVM, and not a quad-head KVM. And besides, quad-port, quad-head KVM units that are USB-based and include sound are priced far too stratospherically for me, not to mention the cost (and difficulty) of finding not only a quad-port, quad-head KVM, but also quad-port video cards for both AGP and PCI-E across Mac, Linux & PC.

Simply put, finding hardware that satisfies all of these requirements is bound to cost well into the five digits, and I am looking for a solution in the three digit range. Hence, my search for a specialized video splitter.

Most video splitters (all that I have found, frankly) split the video up so that the same image ends up on two different screens. I need to have a splitter that emulates a screen that is the combined size of both monitors that are attached to it, so that a different image can appear on each screen.

For example, let's say that I have two 1280x960 screens stacked vertically. I am looking for a VGA “splitter” that tells the computer that it is looking at a monitor with a total (max) resolution of 1280x1920 (because of the vertical stacking). This is so this single resolution can be run from one VGA port on the dual-head KVM. A second “splitter”, handling a second pair of monitors, can be attached to the other VGA port on the KVM.

Remember, I already have a quad-port (for 4 workstations), dual-head (2 vga ports) KVM switch. I am not looking to replace it. And the difficulty of replacing the video cards is even greater -- how will I find quad-head video cards that come for AGP, PCI-E and are Mac compatible as well?

So if anyone can help me, that would be awesome.
September 30, 2009 2:50:02 PM

I think you're SOL. It sounds like you need two video cards each with two outputs to give you 4 screens with their own picture. It's simply not possible with a "splitter" unless it can somehow gather information from your OS, store it in a buffer, have dedicated memory, and drive the monitors, which is what a video card does.

Why do you need a video card that supports PCI-E and AGP? They don't exist. What you're describing seems to be physically impossible unless you upgrade to an SLI/X-Fire rig and get two video cards. If that's not an option, then you're stuck with what you got.
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September 30, 2009 3:14:30 PM

I have three desktops, one four-port, dual-head (vga) KVM, and one keyboard, monitor and mouse. One Desktop is a PC with AGP graphics, the other is another PC, but with PCI-e graphics (single x16 slot, two x1 slots for an installable total of ONE video card), and the third is a Mac Pro that requires a mac-compatible video card. All three desktops have dual-head video cards.

Does that answer your second paragraph? Because I had laid it all out already, for those who cared to read before reacting.

The problem is, quad-port, quad-head KVM's cost well into the five digits. I don't want to spend more than three digits. Then there is the problem getting two video cards to work in a computer which has only one AGP slot, or one PCI-e slot greater than x1. Yes, there are PCI (not PCIe) solutions, but those are so 1998 in terms of performance.

Besides, the splitter only has to emulate another monitor; it doesn't have to store anything from the computer at all. Essentially, such a splitter would emulate the total combined screen size of whatever was attached to it. Say, a pair of 1280x960 screens stacked vertically, to produce (as the computer would see it) a “single monitor” resolution of 1280x1920. The computer would not see two monitors on a single VGA port, but instead would see a single monitor with the larger size. It would then treat it like any other monitor. The only downside is that the two monitors would act as a single larger one, and it would be impossible to “maximize” any app to just one window or another, because the computer would see only one larger monitor instead of two smaller ones.

Remember, I am looking for a solution in the three-digit range, not in the mid-five-digit range. The hardware listed above will NOT be changed, because to do so would be well beyond the range of affordability!! I am an average joe, not a government worker, investment banker or lottery winner!
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September 30, 2009 7:06:43 PM

I think I may have found my own answer… sort of: a USB Video Card.

The key thing is that my KVM is also a USB hub. Three ports, actually; one for keyboard, one for a mouse, and the third for any “shared devices”. Well, what if one of these “shared devices” was a powered USB hub running the Village Tronic ViBook? Or better yet, a pair of them?

Keep in mind, the KVM is a dual-head KVM, allowing me to run two monitors directly from the video card on the workstation currently selected. It is on these monitors that I could have any and all video or high-performance requirements, and I could use any secondary monitors driven by the ViBook dongles just for “placeholder” content that needs displaying. That way, I can have two or three (or even more) small monitors (say, 1280x960) displaying Bittorrent stats or anything else I want to keep an eye on, while my two main monitors handle my main work. Granted, I’m probably going to have to go for 1600x1200 monitors then (in order to maximize the high-performance video area) but at least I can then extend my video area with these dongles.

The only downside is that I have yet to find a USB video card that is compatible with Linux/BSD/Unix.

A video splitter as I initially described it would still be preferable, however. Are there any more suggestions?
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September 30, 2009 8:34:23 PM

THIS IS IT!! THIS IS IT!! PROBLEM SOLVED!!

Matrox Dual Head 2 Go

This appears to solve my problems. I can connect one of these between the KVM and any monitors, and it will allow two monitors to be driven from one VGA port.

Not only does it support XP 64-bit and MacOS, but it also supports Linux (bottom of “specifications” tab), so I can only assume Solaris/BSD/Unix will also be compatible. The latest versions go clear to 1600x1200, and there even seems to be a Triple Head 2 Go under development (although that will probably be overkill for me).

Is there anyone with real-world experience with this product??
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