# Two video signals, Two projectors, One computer?



## Marvalicious (Feb 10, 2011)

We need to run two projectors with separate video signals and would like to do it from one computer. Is this possible?

We usually edit out video content with Final Cut and are considering purchasing Isadora to help with the running. Is there a way to do this without having to purchase an expensive mac tower?


Thanks!
Marv


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## TheDonkey (Feb 10, 2011)

As long as your compyter is powerful enough (it would have to be fairly powerful), and has enough video outputs (you may need to buy another video card) you should just be able to spawn 2 instances of your video player of choice (assuming it allows it, otherwise just use two different players) and drag them onto the second and third "monitors".

If you need audio out though, it may be tougher. You would have to use two separate audio cards and something like VLC where you can choose where the audio goes.


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## metti (Feb 10, 2011)

Matrox DualHead2Go is your friend. I think the vast majority of Izzy users have either that or the TripleHead2Go. I have a couple of the TH2Gs and they work great.


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## metti (Feb 10, 2011)

TheDonkey said:


> As long as your compyter is powerful enough (it would have to be fairly powerful), and has enough video outputs (you may need to buy another video card) you should just be able to spawn 2 instances of your video player of choice (assuming it allows it, otherwise just use two different players) and drag them onto the second and third "monitors".
> 
> If you need audio out though, it may be tougher. You would have to use two separate audio cards and something like VLC where you can choose where the audio goes.


 
The OP can't install an additional video card because they are using a Mac other than the Mac Pro. It is in their posting.


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## Chris15 (Feb 10, 2011)

metti said:


> The OP can't install an additional video card because they are using a Mac other than the Mac Pro. It is in their posting.



Where, pray tell, is that "in their posting"?

Marvalicious said:


> We need to run two projectors with separate video signals and would like to do it from one computer. Is this possible?
> 
> We usually edit out video content with Final Cut and are considering purchasing Isadora to help with the running. Is there a way to do this without having to purchase an expensive mac tower?


 
It may be implicit by virtue of the software referred to, but that requires knowing that FCP is Mac (only) software...


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## museav (Feb 11, 2011)

Marvalicious said:


> We need to run two projectors with separate video signals and would like to do it from one computer. Is this possible?




metti said:


> Matrox DualHead2Go is your friend. I think the vast majority of Izzy users have either that or the TripleHead2Go. I have a couple of the TH2Gs and they work great.


Maybe that works or maybe not, depending on what is meant by "separate video signals". The DualHead2Go and TripleHead2Go make multiple display devices appear as a single greater horizontal resolution display. I would not interpret making the two projectors act as one device as likely being what is wanted based on the comment about sending them two separate signals.


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## metti (Feb 11, 2011)

museav said:


> Maybe that works or maybe not, depending on what is meant by "separate video signals". The DualHead2Go and TripleHead2Go make multiple display devices appear as a single greater horizontal resolution display. I would not interpret making the two projectors act as one device as likely being what is wanted based on the comment about sending them two separate signals.


 
While that is the mechanism by which the D/TH2G gets the video signal from the computer, Isadora has built in functionality that allows you to output video to half or a third of a screen with the specific goal of allowing the Matrox gear to let you output independent signals. I have used mine with TVs and projectors many times and given them entirely different content.


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## museav (Feb 11, 2011)

metti said:


> While that is the mechanism by which the D/TH2G gets the video signal from the computer, Isadora has built in functionality that allows you to output video to half or a third of a screen with the specific goal of allowing the Matrox gear to let you output independent signals. I have used mine with TVs and projectors many times and given them entirely different content.


So it sounds like your recommendation for the DH2G or TH2G is predicated on the assumption that they have Isadora, however I believe that the comment was that they "...are considering purchasing Isadora to help with the running." and not that they have it. Like I said, probably best to define what is really needed first.

Another thing, the DualHead2Go and TripleHead2Go want to see identical resolutions and scan rates for all of the display devices connected, in this case the two projectors. DH2G and TH2G are also somewhat limited in the resolutions and scan rates they support, especially the VGA versions. This is usually not an issue but I just ran into a situation where someone was trying to connect two 1280x720 native flat panels and a 1024x768 native projector to a TripleHead2Go and I'm pretty sure that will not work.


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## metti (Feb 12, 2011)

museav said:


> So it sounds like your recommendation for the DH2G or TH2G is predicated on the assumption that they have Isadora, however I believe that the comment was that they "...are considering purchasing Isadora to help with the running." and not that they have it. Like I said, probably best to define what is really needed first.
> 
> Another thing, the DualHead2Go and TripleHead2Go want to see identical resolutions and scan rates for alof the display devices connected, in this case the two projectors. DH2G and TH2G are also somewhat limited in the resolutions and scan rates they support, especially the VGA versions. This is usually not an issue but I just ran into a situation where someone was trying to connect two 1280x720 native flat panels and a 1024x768 native projector to a TripleHead2Go and I'm pretty sure that will not work.



You are correct that I was assuming they were planning to use go through with their planned purchase of Isadora although there are several other programs that can offer similar functionality such as QLab, VPT, etc. As long as they aren't using PowerPoint or some other consumer grade playback application (Windows Media Player, Quicktime, etc) they should be able to make it work.

You are also correct about the limitations with the VGA version but no (recent) Macs have a VGA output and the Digital Edition is only slightly more money than the VGA version and supports full 1080P.

The need to match resolution is, IMO, the biggest downside to the Matrox stuff but there are workarounds using additional hardware between the Matrox and the projector/monitor.

If we are assuming the OP is a Mac user since they use FCP and specifically say they don't want to have to purchase a Mac Pro, the Matrox line is the only viable option I can think of that doesn't involve upgrading to a Mac Pro or switching to PCs. The USB and network based video cards aren't particularly reliable for anything but the weakest of media/projection applications and there isn't really anything else on the market as far as I can tell.


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## shiben (Feb 13, 2011)

I think Qlab is a better option than Isadora, having both, its a lot easier to work with. Also Qlab costs a heck of a lot less (rent for a dollar a day at school, 3 bucks a day professionally). I believe that Qlab will allow you to work with a double or triple head in a similar but not identical way that Isadora does. Additionally, Catalyst can utilize the double or triple head, but will probably require a macpro.


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## Marvalicious (Feb 21, 2011)

To clarify, one of our projectors needs to project a live video feed plus effects from Isadora (which we are committed to buying). The other projectors will be projecting entirely different material that will at times act as lighting effects. 

The question is, how do I do this from one computer? Right now we only have a an iMac with one video card. So, it seems like we need to buy a better computer (such as a quad core mac tower or something similar) or figure out a separate source to operate from. Money being tight, it's looking like I"m going to have to burn my effects to a disk and operate the second projector from a dvd player and just deal with the effects not being live or editable.


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## museav (Feb 21, 2011)

metti said:


> The need to match resolution is, IMO, the biggest downside to the Matrox stuff but there are workarounds using additional hardware between the Matrox and the projector/monitor.


Just FYI, I asked Matrox what they mean by the displays needing to "run at" the same resolution and pointed out the potential confusion with the terminology as a digital display will always 'run at' its native resolution, but they didn't seem to get that. However, they did confirm that what they mean is that all displays need to accept and display a common resolution and scan rate signal, from among those that the Matrox device supports, however they apparently do not need need to be the same native resolution.


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## SHARYNF (Feb 21, 2011)

museav said:


> Just FYI, I asked Matrox what they mean by the displays needing to "run at" the same resolution and pointed out the potential confusion with the terminology as a digital display will always 'run at' its native resolution, but they didn't seem to get that. However, they did confirm that what they mean is that all displays need to accept and display a common resolution and scan rate signal, from among those that the Matrox device supports, however they apparently do not need need to be the same native resolution.



it is an oddity of the matrox system, usually for instance in windows if you duplicate the display you are forced to set both monitors to the same resolution, but if you extend the desktop, you have the option to have different resolution settings. IMO the matrox unit simply does not have the logic and power to allow for different settings so they force the same setting.

Sharyn


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## metti (Feb 21, 2011)

SHARYNF said:


> it is an oddity of the matrox system, usually for instance in windows if you duplicate the display you are forced to set both monitors to the same resolution, but if you extend the desktop, you have the option to have different resolution settings. IMO the matrox unit simply does not have the logic and power to allow for different settings so they force the same setting.
> 
> Sharyn


 
The issue is that your computer is only outputting one monitor signal so it can only do that at one scan rate and vertical height. It isn't that the Matrox can't handle the processing, it is that their system is fundamentally incompatible with differing vertical resolutions since a computer can't output a single monitor signal with different resolutions for different parts of the monitor. Same net effect though, just nit picking.


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## shiben (Feb 22, 2011)

Marvalicious said:


> To clarify, one of our projectors needs to project a live video feed plus effects from Isadora (which we are committed to buying). The other projectors will be projecting entirely different material that will at times act as lighting effects.
> 
> The question is, how do I do this from one computer? Right now we only have a an iMac with one video card. So, it seems like we need to buy a better computer (such as a quad core mac tower or something similar) or figure out a separate source to operate from. Money being tight, it's looking like I"m going to have to burn my effects to a disk and operate the second projector from a dvd player and just deal with the effects not being live or editable.


 
Wait so your using more than 2 projectors? Another option that you have is to run 2 computers at once, maybe a laptop or something, and you can fire them via MIDI or something together from one cue stack, then you can edit your cue stack and content and not have to worry about the DVD issue. However, yes, your ideal option is getting a bigger computer.


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## metti (Feb 23, 2011)

Marvalicious said:


> To clarify, one of our projectors needs to project a live video feed plus effects from Isadora (which we are committed to buying). The other projectors will be projecting entirely different material that will at times act as lighting effects.
> 
> The question is, how do I do this from one computer? Right now we only have a an iMac with one video card. So, it seems like we need to buy a better computer (such as a quad core mac tower or something similar) or figure out a separate source to operate from. Money being tight, it's looking like I"m going to have to burn my effects to a disk and operate the second projector from a dvd player and just deal with the effects not being live or editable.


Or you can get a DualHead2Go. This is what the majority of multiple projector Isadora users do including Mark, the creator of the program. The manual for Izzy actually includes pretty specific instructions on configuring the stages for Dual/TripleHead2Go output.


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## Kingcaffeine (Feb 27, 2011)

Yep. Izzy w/ DHTG or THTG. Or get a mac mini, install izzy on both controller and mini, fire cues from izzy to the mini. Did that just sound funny? I do this all the time and the izzy forum/instructions are dead easy.


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## ruinexplorer (Feb 27, 2011)

Kingcaffeine, welcome to the forum. I'm glad that you decided to join the conversation. If you could take the time to also jump over to the New Member forum and give us a formal introduction, that would be great. Also, since you seem to have experience with Isadora, maybe you could expand on how you would set this up with the OP's limitations.


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## Kingcaffeine (Feb 27, 2011)

With one computer, a non-Pro Mac, you will not be able to output 2 separate feeds. Unless you use the Matrox box. Even then, you'll need to use some sort of software (in this case Isadora) to parse the "monitor" feed to the correct screen percentages. Izzy is something like $350 and a DHTG is $200. That's the cheapest (except using a DVD...). Setup is exactly what metti said, easy and well documented.

A Mac mini would run $700 for new a little less used. Run the licensed version of Izzy on the iMac and the no-save version on the mini. A patch could be written for the mini which "listens" for OSC or TCP and any video /sound cue could be fired in relative sync with both machines. The patch for a single machine with a DHTG is a little more involved, but doable.

The thing to keep in mind is processor overhead. An iMac will strain with a DHTG with two separate feeds, one being "live video feed plus effects". By spreading the processing out over two, you'd definitely be able to run both feeds at closer to native res for the displays.

The other option would be to rent a Hippo from an AV provider and be done with the whole thing in one shot. I guess it depends on your 1. budget and 2. longer-term needs.


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## sundryaffairs (Dec 25, 2011)

Hi,

I'm a video designer doing the same thing except with three projectors for a theatre production. I need to be able to project to three different projectors with different native resolutions, and would like the projection to be at the highest res possible for each projector. To complicate things - I'm looking for solutions to this - not sure if it's possible, but one of the projecors is a pico, and I'd like to transmit wireless video to it (I realize this may be difficult to gain the highest res in this case), and connect that projector to a live camera feed as well as projecting from Isadora or QLab, so I'll need some kind of switching solution. I have a year to set this up in an ideal way, but budget is a concern. We'll be doing workshops in the meantime to try and test things out so that the projection will be stable. In an ideal world, I would like to use one computer, because there'll be an as-yet unknown operator, and after install, I'd like things to be as simple as possible for the stage manager ad the operator, who'll likely run all cues for sound and image from one source, if possible. So while we rehearse, we'll use Isadora for exploring video live, and once we've settled on choices, we'll render effects in FCP and likely run Qlab for both sound and image. I've googled it, but what's a hippo? And in the mac mini scenario, what's OSC and TCP? How might you set this up? 



Kingcaffeine said:


> With one computer, a non-Pro Mac, you will not be able to output 2 separate feeds. Unless you use the Matrox box. Even then, you'll need to use some sort of software (in this case Isadora) to parse the "monitor" feed to the correct screen percentages. Izzy is something like $350 and a DHTG is $200. That's the cheapest (except using a DVD...). Setup is exactly what metti said, easy and well documented.
> 
> A Mac mini would run $700 for new a little less used. Run the licensed version of Izzy on the iMac and the no-save version on the mini. A patch could be written for the mini which "listens" for OSC or TCP and any video /sound cue could be fired in relative sync with both machines. The patch for a single machine with a DHTG is a little more involved, but doable.
> 
> ...


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## Kingcaffeine (Dec 26, 2011)

"hippo"= Green Hippo Hippotizer (media server). TCP is TCP/IP or a network protocol and OSC is Open Sound Control....another type of network signalling protocol. cues in Isadora can be set up to receive either of these protocols with a "listener", and then the cue can be written to fire after receiving the trigger. So you set up a Mac mini as a slave to the master computer (networked) with all of it's cues written to "listen" for trigger from the master. In my experience, wireless video with a switching solution= pain. But it's do-able....just have to find the right combo of gear.


sundryaffairs said:


> Hi,
> 
> I'm a video designer doing the same thing except with three projectors for a theatre production. I need to be able to project to three different projectors with different native resolutions, and would like the projection to be at the highest res possible for each projector. To complicate things - I'm looking for solutions to this - not sure if it's possible, but one of the projecors is a pico, and I'd like to transmit wireless video to it (I realize this may be difficult to gain the highest res in this case), and connect that projector to a live camera feed as well as projecting from Isadora or QLab, so I'll need some kind of switching solution. I have a year to set this up in an ideal way, but budget is a concern. We'll be doing workshops in the meantime to try and test things out so that the projection will be stable. In an ideal world, I would like to use one computer, because there'll be an as-yet unknown operator, and after install, I'd like things to be as simple as possible for the stage manager ad the operator, who'll likely run all cues for sound and image from one source, if possible. So while we rehearse, we'll use Isadora for exploring video live, and once we've settled on choices, we'll render effects in FCP and likely run Qlab for both sound and image. I've googled it, but what's a hippo? And in the mac mini scenario, what's OSC and TCP? How might you set this up?


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## museav (Dec 28, 2011)

sundryaffairs said:


> I'm a video designer doing the same thing except with three projectors for a theatre production. I need to be able to project to three different projectors with different native resolutions, and would like the projection to be at the highest res possible for each projector.


Are you looking at the same image to three different projectors or the possibility of a different image to each projector?

While it might be ideal to send each projector its own native resolution, what might be more important is finding a single resolution that all of them accept and let them scale that internally.


sundryaffairs said:


> To complicate things - I'm looking for solutions to this - not sure if it's possible, but one of the projecors is a pico, and I'd like to transmit wireless video to it (I realize this may be difficult to gain the highest res in this case), and connect that projector to a live camera feed as well as projecting from Isadora or QLab, so I'll need some kind of switching solution.


Why do you want wireless video, is the projector portable? If you have to get power to the projector then having a physical cable for the video is usually a better approach. The same when budget is a concern. The application and impact of reliability, latency and so on may also be factors. Getting wireless video to work is one thing, doing so within your budget and in a manner that provides the desired quality and reliability may be another.

The live video feed adds an additional set of considerations as does the routing/switching aspect. With multiple sources and destinations you typically need to look at what signal types (HD/SD-SDI, FireWire, VGA, DVI, HDMI, etc.) are involved as well as the related formats and resolutions and as a result may have to look at either gear that works with the signal types involved or incorporating separate signal conversion. Also, if you are thinking of using the image for image magnification then issues regarding latency, time alignment of the video with any associated audio and so on may also be factors.


sundryaffairs said:


> I have a year to set this up in an ideal way, but budget is a concern.


If it is a concern then having some idea of what it is and what it has to cover (e.g. graphics production, cabling, hardware, etc. in addition to the main video gear) would be useful. No use wasting time on suggestions that do not fit the available budget.


sundryaffairs said:


> In an ideal world, I would like to use one computer, because there'll be an as-yet unknown operator, and after install, I'd like things to be as simple as possible for the stage manager ad the operator, who'll likely run all cues for sound and image from one source, if possible. So while we rehearse, we'll use Isadora for exploring video live, and once we've settled on choices, we'll render effects in FCP and likely run Qlab for both sound and image.


Are you thinking one projector to handle the graphic content playback, the live video input, the routing and switching and all the associated processing? I doubt that is practical.


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## gionze (Jul 3, 2013)

Hi all, 
I was really getting a lot out of this thread, but then it ended and I need to know what happened!

Can you tell me what your final set up was? I have a very similar situation coming up soon and am looking for advice on how to set it up. 
The production design includes 4 screens (one upstage center and 2 downstage center, 1 down left, and 1 down right), showing different scenes (some still and some animation, no audio), and at one point a live feed of a close up. 
The throws will be short, 25' at the most and its all front projection. 
We are using Qlab Pro. 
How many MacBook Pros do we need? 
What accessories?
I do not like video black and am planning to use some dmx dowsers.

It's a low budget charity theatre project, so we are hoping to borrow and it all, but I need to make the wish list.
If you have a strategy for this that you don't mind sharing with me and the rest of the world, please share it.

Thanks in advance for any advice.


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## ruinexplorer (Jul 12, 2013)

I have not used Qlab at all, so I can't advise you on this matter. Where is your fourth screen?

Anyhow, instead of dealing with video black in situations like that, I generally default to a logo or some other static image. I don't like looking at blank screens more than video black.


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## museav (Jul 13, 2013)

gionze said:


> The production design includes 4 screens (one upstage center and 2 downstage center, 1 down left, and 1 down right), showing different scenes (some still and some animation, no audio), and at one point a live feed of a close up.


I agree with Ruinexplorer, that seems like either three (one upstage and two downstage) or five (one upstage and four downstage) screens. And when you mention 'showing different scenes' do you mean a) changing images but the same images on all screens, b) always a different image on each screen or c) varying combinations of the same or different images on each screen?


gionze said:


> It's a low budget charity theatre project, so we are hoping to borrow and it all, but I need to make the wish list.


I completely understand wanting to try to support the vision defined, but might it make more sense to assess what budget is available and what realistically can be borrowed before developing any particular concept? I'm immediately seeing things like how realistic is it to borrow five screens and five projectors with appropriate lenses as well as all the related mounting hardware and DMX dowsers? You might want to verify the general concept is practical before going too much further.

I find that this is often one of the most difficult aspects of theatre tech, trying to not limit the creative vision while having to deal with the laws of physics and practical considerations. When the two conflict creative solutions can often get around the conflicts but the laws of physics and practical considerations are rarely as easy to alter no matter how much some may like to think it is possible.


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## gionze (Jul 19, 2013)

Thank you for your advice. I did make a mistake listing the projectors. There is only 1 DC, not 2. I have given the producers a list of equipment and will see what happens next. 
Hope you will continue to monitor the situation!


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## gionze (Aug 23, 2013)

museav said:


> I agree with Ruinexplorer, that seems like either three (one upstage and two downstage) or five (one upstage and four downstage) screens. And when you mention 'showing different scenes' do you mean a) changing images but the same images on all screens, b) always a different image on each screen or c) varying combinations of the same or different images on each screen?
> 
> 
> 
> ...




To answer your question regarding the screens:
c) Its different images most of the time. Occasionally they are the same.
1 UC
1 DC
1 DSL
1 DSR


And as far as budget and equipment we are doing well so far.
We have:
4 screens
4 4K projectors, 
4 dmx dowsers, 
2 Dualhead2go, 
2 macbook pros with full QLab licenses
and 2 G-drives.

Still working on the camcorder and switcher for the live feed.
We will be building the cradles to hang the projectors and dowsers in the theatre.
And we don't have a UPS. Which will probably prove to be our Achille's heal.

Please stay tuned for technical difficulties.


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