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3D Display Hardware/Software Solution?

Cliff posted more than 9 years ago | from the innovative-video-ideas dept.

Displays 27

Daemon8666 asks: "I've searched for three days with no luck. A client of mine has developed a brand new type of 3D display. To make it work, he needs me to come up with a way to synchronize 3 simultaneous video feeds on one box, and output them to 3 separate devices, as follows: Comp playing Videos A, B, and C in sync, and outputting Video A to Monitor X only, Video B to Monitor Y only, and Video C to monitor Z only. He is currently using 3 off-the-shelf DVD players that he controls with one remote (he pushes play, and all three separate DVDs start together), but he really wants a single-unit solution. Any ideas what hardware/software I should use?"

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SMPTE (1)

Datoyminaytah (550912) | more than 9 years ago | (#10875682)

Have you looked into SMPTE at all? Google on that, maybe it'll help, just a guess.

Multihead X and mplayer (2, Informative)

sig (9968) | more than 9 years ago | (#10875713)

Just grab a computer and stick 3 video cards in it. Configure X to run multihead [tldp.org] and then use mplayer [mplayerhq.hu] or xine [sourceforge.net] or totem [hadess.net] to send the videos to your 3 monitors. If you want to be really cool, you could use gstreamer [gstreamer.net] to build a custom app pretty quickly that sent 3 separate video streams to 3 different monitors and kept everything synchronized with a single point of control.

Re:Multihead X and mplayer (1)

Zarf (5735) | more than 9 years ago | (#10878823)

Just grab a computer and stick 3 video cards in it. Configure X to run multihead and then use mplayer or xine or totem to send the videos to your 3 monitors. If you want to be really cool, you could use gstreamer to build a custom app pretty quickly that sent 3 separate video streams to 3 different monitors and kept everything synchronized with a single point of control.

You win the prize! -most helpful and insightful post in this thread-

Re:Multihead X and mplayer (1)

korgull (267700) | more than 9 years ago | (#10897572)

You forget that something needs to be solved first.
How do you keep the 3 different video outputs synchronised ?
xine (and I think also mplayer) do not support these functions (yet).

Anyways, this would defenately be the cheapest and probably the best way to solve this problem at the moment.

Re:Multihead X and mplayer (1)

Zarf (5735) | more than 9 years ago | (#10903202)

Eh, split the same video output three ways and use three identical sync-on-green monitors.

Re:Multihead X and mplayer (1)

prefect42 (141309) | more than 9 years ago | (#10886830)

If we've only got to do 3 it's easy. Buy one card. Matrox Parhelia isn't bad for this sort of thing, or they do a range of quad display cards that lack even that much 3D horsepower.

Simple solution (1)

comwiz56 (447651) | more than 9 years ago | (#10875732)

Grab a computer with 3 video cards, swictch it into multi-moniter mode, and get the 3 players running, 1 per moniter. Shouldn't be that much of a problem.

I dont mean (1)

floydman (179924) | more than 9 years ago | (#10875734)

to troll here or anyting, but dont you think a few pics and a link with extensive description of your scenario would have made it a little bit easier for the intersted audience to give you feedback...

just a thought you know.

Re:I dont mean (1)

Paul d'Aoust (679461) | more than 9 years ago | (#10876233)

I'm guessing that this project is potentially patentable, so the client probably wants to keep the amount of information leaked to a minimum.

Re:I dont mean (0)

Anonymous Coward | more than 9 years ago | (#10969038)

Bingo.

I concur. (1)

jgaynor (205453) | more than 9 years ago | (#10875788)

dont you think a few pics and a link with extensive description of your scenario would have made it a little bit easier for the intersted audience to give you feedback

Yes, And easier for me and my engineering buddies to replicate and patent before you can. What are you thinking posting this to /.???
(I would never do that of course, but I bet theres someone at CompUSA right now picking up some extra hardware to do just that!)

Re:I concur. (0)

Anonymous Coward | more than 9 years ago | (#10876251)

and good luck trying to actually do anything with said patent in the face of such blatent prior art :)

Re:I concur. (1)

shaitand (626655) | more than 9 years ago | (#10878322)

Yeah, cuz damn, we all know some guy posting on slashdot saying that a guy he knows made one is SOLID prior art!

Simultaneous video feeds (2, Informative)

legirons (809082) | more than 9 years ago | (#10876178)

You need hardware-synchronised or "genlocked" video cards, which use cables to synchronise the drawing of each frame. Naturally, you will be using 3 graphics cards in 3 graphics computers, with the rest of your application running on one or more additional machines.

Graphics cards which can do this are things like the nVidia Quadro FX3000G - the G stands for genlocking. Yes, they cost more than the normal version.

Re:Simultaneous video feeds (1)

Paul d'Aoust (679461) | more than 9 years ago | (#10876265)

I think that, for the time being, commodity cards, a single computer, and distributed multihead X would be fine. Pro cards that support a perfectly synced video stream might be overkill if this is just a rig used for experimentation: best to start out cheap, get a proof-of-concept, and then go to the big guns later.

Of course, the one problem is that you'll be stuck with rather slow PCI cards if you want three cards in one computer.

Re:Simultaneous video feeds (1)

Paul d'Aoust (679461) | more than 9 years ago | (#10876363)

(addendum: I don't know what sort of software tools you could use in order to get the video streams synced. I think that'll be the most difficult question to answer. Perhaps VLC or xine can be run in a daemon mode? that way, you could run three instances, one after the other, and when they've loaded themselves and the videos into memory -- which would cause them to be out of sync -- you could send a command to all three to start playing at the same time. On the other hand, the comment a previous poster made about cobbling together something using Gstreamer abstraction layer might be easier...)

Videos in memory (1)

phorm (591458) | more than 9 years ago | (#10892987)

You could cheat on this. Have a nice big ramdrive, preload the videos, start 3 Xine instances - each pointing at a video file but not set to play - then once all three have started, tell them to start playing.

Since the files are on ramdisk delay should be negligable between the 3 instances as far as startup...

2. ??? (1)

Eil (82413) | more than 9 years ago | (#10876432)


I wonder if he had planned to profit from this innovative idea of his before it was posted to slashdot.

Re:2. ??? (1)

100lbHand (676832) | more than 9 years ago | (#10877212)

1. read slashdot
2. ???
3. profit!!!

Re:2. ??? (0)

Anonymous Coward | more than 9 years ago | (#10969175)

You think you can engineer it up before he patents it, shoot.

Extra wide frame (2, Interesting)

Descartes (124922) | more than 9 years ago | (#10876514)

I agree that you should use 3 video cards in one machine, but I think you should make all three videos into one extra wide frame.

So if it's 640x480 per frame, but squish them all together in a 640x1440 mpeg and let the output display across the three devices. That stops you from having complex software to synch three seperate players.

Re:Extra wide frame (1)

mpaon (787734) | more than 9 years ago | (#10902660)

You possibly could get away with 2 video cards. Most of the ones i've bought recently have a VGA and a DVI port... get a dvi to vga converter (or vice versa) and set them up as different displays. You might even be able to use svideo, letting you use just one card, but the quality isn't that great.

How to... (1)

ratboy666 (104074) | more than 9 years ago | (#10878346)

Ok... here are some ideas.

First, multiple video streams can be interleaved into a single mpeg transport stream. Each of the streams has its own 33 bit decode/present timestamps, and you can (for this application), ensure that they are synchronized.

Next, the video output can be gen-locked. One free-running video, and feedback from the DAC to keep the other two video outputs synchronized. There are some chip solutions that can do this, and several board solutions as well. To make this viable, you probably want a chip-level solution.

Now, the client currently uses 3 dvds, synchronized with a remote? That's very, um, coarse, so gen-lock is probably not even needed -- just the DTC/PTC should do very nicely (and MUCH more accurately). Of course, we assume a "single" (stereo/5.1/whatever) sound stream in the mpeg.

For a board level solution, look at 3xXilleon, or something like that.

Ratboy

Too complicated (3, Funny)

mboverload (657893) | more than 9 years ago | (#10884583)

Just use a beowulf cluster. Around here it seems they can do anything.

I doubt it... (1)

cr0sh (43134) | more than 9 years ago | (#10889149)

A client of mine has developed a brand new type of 3D display.

Yeah, right. I am not saying it is not possible, it very well might be. But when you look back at the history of 3D imagery, patents, methods of viewing, eye-brain trickery, etc - it seems like it all has been done before, in one manner or another.

Furthermore, none of the prior art, with the exception of true holograms (and perhaps a few of the volumetric 3D display systems), manage to convey true depth where the eye can focus on any one part of the image - most cause the eye to remain focused on one image plane, which leads to massive eye strain in the long run (which is a huge issue with most immersive 3D head mounted displays for VR use)...

Re:I doubt it... (1)

cr0sh (43134) | more than 9 years ago | (#10889443)

damn - left off the end tag...

Dedicated video mixing solution (1)

krugerm (194029) | more than 9 years ago | (#10896491)

Instead of mucking around with multiple video cards, hacking mplayer, or rolling your own system that can control multiple genlockable video cards (i assume you'll need this, using a 3d display) I would recommend going with a dedicated solution such as newtek's video toaster. (Disclaimer - I am in no way affiliated to newtek.)

VT gives you 4 composite / component outputs, and is capable of handling multiple streams at once. Simply amazing for real-time compositing. (Disclaimer #2: I've never worked for a large digital house either, so what I'm impressed by might be run-of-the-mill in the industry. *shrug*)

I would suggest that this would save you a lot of time / effort, but that it might give you a slightly over-engineered solution.

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