Dual Monitor Pro Needed - Virtual Dr Forums-Computer Tech Support

ProfessorU · #1 December 21st, 2002, 09:14 PM

Here's what I'm trying to do:
Playback video across dual displays at a total of 2048x768 resolution

Here's what I have:
.avi file made with Premiere
P4 2.4GHz in WinXP Home
GeForce 4 Ti4200
2 projectors capable of 1024x768

This would be really cool if I could get it to work, but I can only get video to playback on one monitor at a time, even in windowed mode. Is this possible with different drivers/software playback? Is this possible with different hardware?

labyrinth · #2 December 22nd, 2002, 08:34 PM

Are you trying to go through the twin projectors to make a full movie screen? I may not be a pro but I may be able to help. I just went and checked out your video card you have S-video out, you would need a card that has dual monitor support.

patweb · #3 December 23rd, 2002, 11:46 AM

I have tried many different DVD decoder/ players to no avail on the secondary display. If you cross the two displays, they all crash. I have had trouble with most non-standard uses of the Secondary display (some applications simply change the secondary to the primary display when you try it. All I was trying to do was make stuff on the Primary display work the same on the secondary. I don't think Windows supports it (it IS much better than. say Windows ME dual display support).

labyrinth · #4 December 23rd, 2002, 02:49 PM

To run twin displays, which Windows does support, you need: A video card which supports twin output, or you need twin video cards. One AGP, and one PCI. Both of my computers are running ATI AGP cards and both support TV out by way of S-Video. I can run a single monitor and simultaneously run an S-video to my TV in the living room, (about 25' away). So DVD can play to TV, using the computer. I experimented with twin moniters. To do this you must install a second video card, (PCI). Reset drivers and then you can output across twin screens in a number of ways. If I am getting close to explaining what you want to do post again explaining to me in deatail what you are trying to accomplish, as well as harddrive rpm, 5,400- 7,200 and a link to your video card's specs.

ProfessorU · #5 December 23rd, 2002, 09:18 PM

Wow, thanks for all the replies! Since there's so much interest, I'll cover the project in more detail.

We're combining bluescreened video of actors with synthetic backgrounds. This video is being rear-projected behind live stage actors. We've overcome a lot of the technical issues, but 1024x768 isn't enough resolution to make any video look reasonable when your actors are life-size on a ten foot tall screen, especially since the useable resolution would be closer to 1024x512, after fitting the projection to the size of the screen.

So to answer the questions about the rig, I know it has the raw HP to crank this video out. It's a 7200 RPM drive, but if I needed to, I could pull a 5-drive 15,000 RPM SCSI RAID 5 array out of my server. I think I'll save that for when I'm doing movies! The video card is from Siluro, and uses the GeForce 4 Ti4200 chipset. The board is standard reference design and is cooled enough to overclock well if I need it to. It supports dual monitors through an analog and DVI output. I already span my desktop across both monitors with much success. It does have s-video TV out, which can be used simultaneously with either one (but not both) of the other outputs, but I'd much rather use the analog and DVI outputs to keep the resolution higher. I'm using the drivers from NVidia, but I've tried the ones from Siluro and they appear to be the same drivers rebranded (as I would expect).

My problem is much like patweb said. Windows has no problem supporting many monitors, but it only wants to support one monitor powerful enough to display any video or 3d on.
Maximum PC in their latest (1/2003) mag says,

"Some NVidia boards will let you stretch a 3D game across two monitors if you use the stretch mode setting instead of setting independent resolutions and refresh rates for your two monitors. In order for this to work, your game must recognize the odd refresh rate that it will have to run."

I take this to mean that it might be possible to get my rig to work if I use a different driver set and find a compatible piece of software. Maybe someone out there has already done it.

Thanks for all the feedback so far. I'm hoping I'll figure this out without having to install another OS. Any ideas are welcomed.

labyrinth · #6 December 24th, 2002, 11:25 AM

ProfessorU: I know just the guy to get you an answer from. He's a stage hand who works with computer-to-video projectors for corporate symposiums, in places like the Mosconi Center in San Francisco. It'll take me 24 to 48 hours to get you an answer if you can wait that long.

ProfessorU · #7 December 24th, 2002, 02:22 PM

You will be my new favorite person if you post back! Fortunately I have some time. Thanks, I'll be waiting.

patweb · #8 December 26th, 2002, 02:01 PM

You can use the video out on the GeForce card to display on a big screen TV ,or even an HDTV monitor (which has the same aspect ratio as widescreen). Assuming you are doing the video editing live.....

ProfessorU · #9 December 26th, 2002, 09:39 PM

Do you know anyone with a ten-foot-tall HDTV I can borrow?

Even standard HDTV at it's highest resolution is 1920x1080i and since we want progressive (not interlaced) it actually caps out at 720 pixels in height. Plus our target aspect ratio is 2.2:1, not 16:9. Maybe if we only cast people under 4' tall...

patweb · #10 December 27th, 2002, 11:15 AM

Sorry for making the suggestion.

ProfessorU · #11 December 27th, 2002, 03:56 PM

I didn't intend to sound mean. We just finished building the screen today. It's approximately 22 feet wide and 10 feet tall. It looks AWESOME but it will look even better if we get this dual video figured out.

I should be hosting a LAN party instead of a play!

DocDon · #12 December 27th, 2002, 08:50 PM

If I understand you correctly, you are trying to show some sort of a moving video image onto a rear projection screen behind an actor. That is doing things the hard way. Studios usually use a blue screen for this sort of thing and PC software can use the same technology to merge a background image with a blue (or even green) screen of your actors.

Per my reading (I forget where, maybe someone else can supply that), most of the programs which display video are hard-programmed to display only on the main logical monitor, however you have that setup. This is why you cannot watch DVDs on the second monitor or even on the TV (if the TV has been setup as a second video device) unless the second monitor (or TV) is setup to reproduce the main logical monitor image.

Example: On All-In-Wonder systems (I have an ATI 8500DV 64MB AIW in a system with an Athlon 1400/266 with 256MB on an Epox 8K3A motherboard - my 17" CRT monitor is the main monitor and my 32" TV is my secondary monitor with WinXP), the first (main) "logical" display screen is represented by the left button (which shows only a single monitor) of the pair of buttons at the bottom of the AIW setup display for each monitor. Both physical monitors can reproduce this image and this is how I send DVD images to my monitor and TV. The right of the pair of buttons shows a pair of overlapping monitors and causes the display to show the second of two images as a screen extended across both monitors. Either of the physical screens from the AIW outputs can be setup as the main (first) logical screen. At least one of them must be so designated.

To run DVDs on the main TV, that physical monitor must be set as the main logical screen. Anything else causes everything but the DVD video to show up on the physical screen. The DVD video will only show up on the main logical screen. I have tested this on the ATI DVD player, WinXP's Media Player and the InterActual Player. All play the DVD video only onto the main logical screen.

I am a user and am not a movie maker or a professional in the area. I hope some of them will chime in on this subject and let us know how to best do this.

Good Luck!

labyrinth · #13 December 28th, 2002, 11:13 AM

Professor: I haven't forgotten about you. My pro is out of town for the Holidays. Should be back today. Hopefully will post by tomorrow.

DocDon · #14 December 28th, 2002, 12:31 PM

Professor,

I believe a couple of high-end DLP projectors are available (about $30,000 each - I can find out if you're interested) which can display 1920 x 1080p. However, most displays max out at 1920 x 1080i, as you noted.

Pertaining to your actual post about having a moving image spread across two monitors or projectors, per my prior post, I don't believe it can be done. Also, per memory, it is limited by the software displaying the image and NOT in Windows itself. Per my reading and limited experience, no software displays movie images on other than the main "logical" screen. Still, your single large screen should be displayable from one of the $30K DLP projectors I mentioned earlier. And you could run the same image on two separate projectors onto that screen (repeated image).

In terms of resolution, I seem to remember that many of the digital effects in earlier Star Wars movies were done on approx. 1080p resolution using early Sony digital cameras.

ProfessorU · #15 December 29th, 2002, 02:38 AM

Again, thanks to everyone for the contributions. Incidentally, we are using bluescreening (greenscreening) for the video of the actors (mostly because our digital camera caps out at 720x480) But since this show has a live element, we want to be able to project behind the live actors in realtime. On video, this would be immeasurably easier. (If anybody wants some color keying tips, just ask!)

Unfortunately, it will be a while before I can convince the director for another 300 benjamins for the technical end of this project. The projectors we have available are loaners... and it's a recent development that there are two relatively new ones available from the same source. They claim to be HDTV compliant... but I'll have to test their maximum resolution myself this weekend. If we can't get the dual monitor thing to work, maybe that will be our best solution. I'm a little worried about brightness, also. The luminance of a projection stretched across such a large space might not be enough. Again I think this will show itself in testing. The final workaround idea in my mind is a dual-PC rig... but syncronizing the two projectors (at least on fade in and out) is probably more than I can handle.

labyrinth - thanx for the update! I'm still hopeful.
patweb - thanx for sticking through this far.
DocDon - thanx for the research and kind words. I must admit that everything that I have read and seen says that windows will only support video or 3D on the primary monitor. My card will support one or the other of the displays, but not both, unless they are cloned, like you said. Maybe this is an OS thing? I know the Matrox Parahelia supports triple-monitor 3D through some driver twisting. Maybe the solution is there somewhere. Or in a different OS.

Having the concepts worked out on paper... two thousand pixels across twenty-two feet, is completely different than having it actually in front of you. HDTV resolution might look alright... I'll keep everyone posted on the tests.