[QLab] Multiple video outputs

[stbo]

Qlab's video patches seem to be able to cope with a load of video
outputs - what do people recommend/use for driving up to e.g. 8 video
outputs?

I am looking at possibly having to drive 8 projectors, each with a
separate video playing on each projector, rendered possibly in SD -
800 x 600 - but will have control over this.

New to Apple - so any pointers appreciated.

Thank you.
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[Matthew Haber]

The only way to get 8 outputs from a single Apple computer is with a Mac Pro. To drive 8 outputs you will need to add additional graphics cards beyond what they offer as BTO options and you will need a bunch of RAM and some pretty fast HDs or SSDs.

Matthew Haber
Lighting & Projection Design
Isadora, Quartz and Watchout Programming
www.matthewhaber.com
617-435-9257

[Christopher Ashworth]

Matthew is right on. 8 outputs to one Mac Pro is the theoretical maximum.

In practice it will probably be better to look at using a number of less powerful machines each driving fewer screens.

[stbo]

Chris,

Thanks for the info. Unfortunately this creates a problem as I want
to have the video playing as one large image. The issue here is
synchronising the start of the videos across multiple machines,
otherwise the edge-blended image will not work, as there will be a few
frames difference between the machines.

Any suggestions on how this might be achieved?

Clearly I have a lot to learn...

Thanks.

[Christopher Ashworth]

Hi Stewart,

Good question. Well, one possible answer is that we have a new product in development intended to provide synced video playback across multiple machines.

(I suppose this is as good a time as any to reveal something about it.)

It's still in internal testing--not yet out in the hands of beta testers--but we're hoping to get it into beta very soon.

We're tentatively calling it "Loq", and the idea is that it's a relatively small/inexpensive program to put on multiple machines. It listens to incoming timecode and then plays back video cues locked to that timecode. (A loq document is a list of video cues with timecode assigned to each one)

As I said, it's still being tested and bugs are still being fixed, but in theory it should provide synchronized video playback Across multiple machines.

If that sounds like it might be useful, I could send you a beta to try when it is ready.

Others on the list will, I am sure, have other suggestions that I'm not thinking of at the moment. (I wonder if there are other, non-figure 53 products that can solve this problem without too much expense? Or is cost not an issue?)

C

(mobile)

[Søren Knud]

Den 27/05/2011 kl. 14.32 skrev Christopher Ashworth:

> Hi Stewart,
>
> Good question. Well, one possible answer is that we have a new product in development intended to provide synced video playback across multiple machines.
>
> (I suppose this is as good a time as any to reveal something about it.)

Ohh shit, this sounds great! This is the only feature on Watchout that I am really attracted to. Exciting!

> Others on the list will, I am sure, have other suggestions that I'm not thinking of at the moment. (I wonder if there are other, non-figure 53 products that can solve this problem without too much expense? Or is cost not an issue?)

Meanwhile, i suppose Quartz Composer Visualizer is mean for this, but i have newer had the balls to try it in a production :)

[Matthew Haber]

I'm not really sure how I would go about keeping multiple videos across multiple computers in sync with QLab. There are multiple, easy ways to start the videos in sync but keeping that way is a little trickier. If you are open to looking at other programs, several users (myself included) have made user actors/patches to do this via OSC with Isadora which is relatively inexpensive. If money is no issue, then something like Watchout would be perfect though Watchout is a per-output licensing scheme so it would come in a round $20k plus the cost of 9 computers. A financial middle ground would be something like Arkaos, Pandora's Box, or Catalyst which would definitely allow you to keep playback synched up but would be able to do a few outputs from each license/computer to save. Someone just mentioned Quartz Composer as well. It is possible to do this via QC and I have done it once but it is a little bit tricky compared to pretty much anything else and QC is also pretty much imposs
ible to actually cue a show entirely in QC. It is free though.

Matthew Haber
Lighting & Projection Design
Isadora, Quartz and Watchout Programming
www.matthewhaber.com
617-435-9257

[Søren Knud]

Den 27/05/2011 kl. 14.51 skrev Matthew Haber:
> Watchout would be perfect though Watchout is a per-output licensing scheme so it would come in a round $20k plus the cost of 9 computers.

You can run 4 screens on 1 player by using Datapath X4 meaning 3 computers total (1 controller and 2 players). Still expensive of course.

> A financial middle ground would be something like Arkaos, Pandora's Box, or Catalyst which would definitely allow you to keep playback synched up but would be able to do a few outputs from each license/computer to save. Someone just mentioned Quartz Composer as well. It is possible to do this via QC and I have done it once but it is a little bit tricky compared to pretty much anything else and QC is also pretty much imposs
> ible to actually cue a show entirely in QC. It is free though.

I have controlled QC very succesfully with Artnet, by using the Pixelnode by Synthe Fx. Also with multiple computers edgeblending. BUT it was stillpictures, and I am not sure that i would dare to try to sync video via the QC Visualizer.

[Stephen Pruitt]

Stewart,

I just worked on a project where I did a very similar thing to what you're talking about doing... in fact, I'm putting together a "how-to" on it, since the issue comes up so often on this email list. We had 5 seamed projectors on three wall, two in front of house shooting at set pieces that dropped in, and two shooting at the floor. Here are some things I discovered...

The limits of what the single computer can run all at the same time are most likely going to fall short of all 8 (or 9) video outputs if you're trying to run simultaneously. In practice, what I found is that I could run 5 screens smoothly, if I managed all of the cues around that one, to avoid stutters when starting and stopping. A newer computer might manage it slightly better, but I had just about the best system you could ask for working on it (2008, 8 cores, 16GB RAM, 2 SSD drives, plus a RAID, a 5770 + 3 @ GT 120 Video Cards, for nine total outputs)

As we built the system up, we actually found that just having 10 screens (9 projectors + the main monitor, by using a triple-head) caused a strain on the system. We eventually cut two projectors, and the computer was much happier with 7 + 1. 

Are you running more than just one cue? From your questions, it almost sounds like more of an art installation than a show...maybe you're just starting them all and letting it run? If that is the case, you might just get away with it... I found that the number of videos I could run simultaneously was larger than the number I could use when starting and stopping things. Loading, starting and stopping other cues, even if invisible, would cause the multiple projector images to stutter. 

I found on my system, doing that much stuff, that the processor was the bottleneck. Our animator chose to render at 800 x 600, and I was doing a lot of scaling anyway, so I didn't complain, but if I had it to do over, I'd have insisted that she work at the native resolution of our projectors - 1024 x 768. If you have the money to stack your system with good SSDs (you can get OWC drives for as little as $99 for a 40GB drive, which is all you need to hold content) and enough RAM, then your processor will definitely be the weak link. 

Getting all eight to start and be accurate within a frame is going to be difficult. but depending on the motion, you might find that you don't need them to be perfect. Play with starting cues and pausing them. I found that it was far easier for the computer to restart a paused video than to start it from scratch, so in a few places I would start one with 0 opacity, pause it a tenth of a second or so later, then restart with a 0 count fade up when I actually needed it. Ugly, but it worked. The ideal for an installation would be to give yourself a few seconds of countdown, start and pause each cue individually, using the postwait on the pause and the countdown to set your pauses so that they all happen at exactly the same place in the video, then restart all 8 at once. I have no idea if that would work for you, but given how things worked for me, it would have a good shot of getting you in sync. 

We had one piece of video in particular that had a lot of movement in it, and I didn't have any trouble getting it frame synced, but it was only 3 images on 5 projectors (one wide one built with the triple head in mind, then one for each side of it), not eight. 

Good Luck! 

Stephen

Fluxion Scenic and Light

www.fluxiondesigns.com

See my photography at Flickr: http://www.flickr.com/photos/seamonkey78704/sets/

"Society is like a stew. If you don't stir things up occasionally, all the scum rises to the top." - Edward Abbey

[Christopher Ashworth]

On May 27, 2011, at 9:48 AM, stbo wrote:
>
> What type of timeframe are you looking
> at for Loq betas to be available?

Within the next couple of weeks.

> Also, will each machine that has
> Loq on it require a licensed copy of Qlab?

Loq can be used completely independently of QLab. If you use it with QLab, you'd only need one machine running QLab (to generate MIDI Timecode sent to the Loq machines).

> Also, presumably Loq is
> designed to work with Qlab only? For example, could I use it to
> trigger anything running on a windows machine (I know...)

Loq is designed to work with anything that generates timecode. It is not triggering other software, but it is actually playing back the videos itself, based on incoming timecode.

> @Chris - I know you have hinted at some of the V3 features around the
> QC integration. I will avoid asking the obvious timescale questions,
> but are you in a position yet to give any sort of information about
> the QC-integration facilities in QL3? For example, at present, there
> are very few properties available (size, opacity etc) - and so it
> would be useful to understand what the thinking is here.

So, the present properties were the ones that QLab itself was designed to use. Exposing them is handy, but definitely limited since there aren't very many.

We are definitely interested in trying to expose more (and more flexible) QC parameters in V3. I won't promise it, since that part hasn't been built yet. But that's the hope. Better/deeper QC integration is something we're generally interested in.

-C

[Matthew Haber]

FWIW, it is totally possible to do edge blending in QLab via QC. Also, you may already be aware of this, but it is not too difficult to assign a QC patch to a QLab video cue and then control addition parameters via a separate MIDI cue, which gets around the passable properties limitation. It would be nice to see that processes streamlined a bit in the next version, though.

Matthew Haber
Lighting & Projection Design
Isadora, Quartz and Watchout Programming
www.matthewhaber.com
617-435-9257

On May 27, 2011, at 9:48 AM, stbo wrote:

> Folks,
>
> Thank you all for the input - very encouraging.
>
> @Chris - I have some time to plan this - I have to be in a position to
> give a go/no-go by the end of the summer so I am starting to ask all
> the questions now to plan... What type of timeframe are you looking
> at for Log betas to be available? Also, will each machine that has
> Loq on it require a licensed copy of Qlab? Also, presumably Loq is

> designed to work with Qlab only? For example, could I use it to
> trigger anything running on a windows machine (I know...)
>

> Budget is an issue - so watchout is out of the question - it is an
> amateur production, but I am trying to push the boundaries a bit...
>
> To the other question - it is a show - not an art installation, and
> the footage is mainly the actors in the show filmed previously against
> green-screen and various backgrounds and VFX added in, or motion VFX
> as a form of electronic set...
>
> It looks like 2 decent machines, each with max 6 projectors + console
> with Qlab installed on both, would give me plenty of scope.
>
> I currently use Grand VJ when I need edge-blending - I really like
> Qlab, and so if edge-blending becomes possible in V3 I could use Qlab
> for everything. I have to say the edge-blend facility to GVJ works
> like a treat - so far across 3 projectors only though...

>
> @Chris - I know you have hinted at some of the V3 features around the
> QC integration. I will avoid asking the obvious timescale questions,
> but are you in a position yet to give any sort of information about
> the QC-integration facilities in QL3? For example, at present, there
> are very few properties available (size, opacity etc) - and so it
> would be useful to understand what the thinking is here.
>

> Thanks again for all the suggestions/advice.

[stbo]

[Michele Cremaschi]

Dear,

there's a free software that says do exactly what you need. But i have
never tested it. It's Multiscreener, said to be "Free Synchronized
Multi-Channel Video Player". You can download it from:
http://www.zachpoff.com/software/multiscreener/

bye
michele

[Matthew Haber]

Wow, I hadn't seen that before so thanks for the link. He also links to something called ygbox which is a similar QC based solution. I am going to download that and take a look at the patch but it looks like a good jumping off point.

Matthew Haber
Lighting & Projection Design
Isadora, Quartz and Watchout Programming
www.matthewhaber.com
617-435-9257