Video Screens/Surfaces

[nizer]

I have been trying to get my head around 2 things in Qlab 3. 

1. Screens/Surfaces

So if I understand this. If a video surface that I use is no longer available, I then have to go into all 200 video cues I have and manually change the video surface to one that is available? In v2 I would just patch it to the screen in the venue?

2. What is a slice? There is no info on it other than it is for looping video and audio. Is there a manual for Qlab 3? 

[Mike P]

On May 18, 2013, at 4:34 PM, nizer wrote:

> I have been trying to get my head around 2 things in Qlab 3.
>
> 1. Screens/Surfaces
> So if I understand this. If a video surface that I use is no longer available, I then have to go into all 200 video cues I have and manually change the video surface to one that is available? In v2 I would just patch it to the screen in the venue?

Someone correct me if I get this wrong.

Surfaces are virtual constructs. When you launch QLab, surfaces are created for each output device you have connected. This are not dynamic, but fixed to that output. However, you can create new surfaces using the same output which can be changed on the fly. So, if you approach a video task with a surface you created instead of the one QLab builds, you can change it when you need to change the output and that will change all your cues.

Just tried to mock this up. I created a new surface with a separate monitor and set up a Video cue for it. Then I shut down QLab and disconnected that monitor. When I relaunched, the surface stayed defined in the file, but the output mapped onto it was invalid so my cue showed an error. I fixed it by editing the surface, removing the output that wasn't connected and adding a different output. My cue was happy again and the output worked fine.

The suface QLab created automatically was also present, but near as I can tell there's no way to set a new output for it. This means you will have to think ahead and create those surfaces for changeable outputs if you think you will be using this file on a different rig.

Could there a feature request to add a way to change the output for a surface QLab creates?

>
> 2. What is a slice? There is no info on it other than it is for looping video and audio. Is there a manual for Qlab 3?
>

I got confused too, but I think I figured it out. A slice appears to be the point a file is cut into separate pieces. The slice markers can be added as desired in the Time & Loops tab. From there you can play with loops and devamps.

There are some good videos set up to get started in Version 3.

http://figure53.com/qlab/documentation/

I cobbled together a reference guide on my own which you can get at this link. Start with the videos though. They're very helpful. I'm not part of Figure53, just a happy user :-)

http://mdpostdesign.com/Samples/Sharing/QLab_Book.html

Mike Post
(601) 307-8657
mdp...@mac.com
http://mdpostdesign.com

[nizer]

Great post. Thanks for helping me get my head around this. That is exactly what I did and it works great.

Slices is something I really don't need, now that you explained it.

My last issue is quartz composer. The Syphon plugin that brings QC into Qlab via a camera que is impossible sluggish. I have some custom QC renders that I can't recreate via the image in and out stuff. Thinking I may have to just run QC in the background and "reveal it" when needed with AppleScript.

Again thanks for chiming in here.

I'll check out your link

[Mike P]

> Great post. Thanks for helping me get my head around this. That is exactly what I did and it works great.
>
> Slices is something I really don't need, now that you explained it.
>

Glad I could help :-) I think you might be surprised about how Slices could help you out. See if you can get your head around how Devamp works and you might find some uses. It's pretty damn impressive.

> My last issue is quartz composer. The Syphon plugin that brings QC into Qlab via a camera que is impossible sluggish. I have some custom QC renders that I can't recreate via the image in and out stuff. Thinking I may have to just run QC in the background and "reveal it" when needed with AppleScript.

Can't help you here. I've never used Syphon (but I should look into it). There's been a lot of talk about it - maybe something will shake loose.

Best!

[Lucas Krech]

Are the Quartz renderers doing projection mapping? If not what are they doing? I ask because if it is not context dependent you may be able to prerender and record via screen capture to do a simple playback.  Also, I have found that many of my Quartz patches need to be rebuilt to optimize once I've figured them out. Remember QC is just a graphic interface/abstraction to a bunch of code. So if the build was haphazard and a product of trial and error the underlying code that is running will be equaly sloppy. If you are getting anything less than 60ish frames a second it may well be worth a rebuild.

I have not explored the current QLab build much, but you could build your own Syphon receiver as an effects patch to test responsiveness. I did this in beta and got very fine response so my hunch is the final implementation is good and the sluggishness may be a function of your patch not Syphon or QLab.

Also, Slices are well worth exploring. 

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[Willo]

Here's a simple example of how slices are really useful:

I have a cue which is a gun battle. The audio file has a long selection of randomly spaced rifle shots, sometimes two in quick succession. the gunshots all have slight echo and a natural decay.

In the middle of the battle, an actor reaches a certain position and delivers a speech. The sound has to stop. It then picks up again after his line, until the next actor speaks, and so on...the sound interrupted six times.

Previously, I would have to hit a key to stop the gunshots cue, but because there was no easy way of watching the action and watching the audio wave file, there was a good chance that I'd stop it just after another gunshot....which would create an awkward cut-off in the decay of the sound. I could solve it to an extent with a fade cue rather than a dead stop, but that still resulted in a noticeably unnatural fade of the decay, and would not prevent a gunshot sometimes being heard to fire during the fade, which also sounded unnatural. I could try to delay cuing the stop if a gun had just been fired, to allow for the decay, but the unpredictability of the audio and the action meant it was all a matter of luck to get a truly satisfactory ceasefire, and usually there were two or three awkward moments within the cue sequence.


Now, with slices, I look at the audio file and can clearly see the attack of every gunshot. I put a slice marker directly before each new shot, or double shot. My audio is now separated into many chunks of one or two gunshots at a time, and every chunk has a complete and natural decay.

So now, when I have to cue the sound to stop, I use a Devamp cue instead, and no matter where I am in the file, the audio will continue playing the current chunk of gunshot and decay but will stop at the next slice marker, before the attack of the next gunshot. I don't need to know where I am in the audio, the sound will always play out naturally, and stop before being interrupted by the next gunshot.

Nothing to do with loops, but very useful to allow the sound to stop at a predicted point, even when the cue itself is unpredictable.

Cheers,

Craig

[nizer]

Great explanation. I will start pondering on how I can use this.

[Christopher Ashworth]

On May 18, 2013, at 4:34 PM, nizer <ma...@nizer.com> wrote:

> Is there a manual for QLab 3?

We are working on adding more documentation, which will be available here as it is created:

http://figure53.com/qlab/documentation/

In addition to Mike's documentation which he shared, Stew Ives has also been hard at work on the wiki:

http://wiki.figure53.com

In particular:

http://wiki.figure53.com/QLab+3+Video

http://wiki.figure53.com/QLab+3+OSC+Video+Effect+Controls

[Christopher Ashworth]

On May 18, 2013, at 6:04 PM, Mike P <mdpost...@gmail.com> wrote:
>
> The suface QLab created automatically was also present, but near as I can tell there's no way to set a new output for it. This means you will have to think ahead and create those surfaces for changeable outputs if you think you will be using this file on a different rig.
>
> Could there a feature request to add a way to change the output for a surface QLab creates?

Yes, this is a good request and something we realized only relatively recently was missing in version 3. I've just added a ticket for us to work on this.

[Mike P]

On May 19, 2013, at 10:26 PM, Christopher Ashworth wrote:

> Yes, this is a good request and something we realized only relatively recently was missing in version 3. I've just added a ticket for us to work on this.

Excellent! Many thanks!