2 cameras for a live show

[Bastien Dausse]

Hi, 

I'm actually creating a show, and I'm not very good for the technical things. I hope I will find an answer here !

I was thinking to use Qlab for the stage management. I'm using 2 cameras on stage and a video projector. I would like to do live video projection. I need to connect my 2 cameras (mini-hdmi) to my mac mini and then connect my mac mini to my video projector.

I will not do live video projection with the 2 camera at the same time. I use one camera, then the other in another scene. 

So I have different questions: Do you think Qlab is right for me?

Which cable should I use? I heard  that HDMI is not very good for long distance (I will lose quality). And I think I will have 30-50m of cable (It depends of the size of the theatre).

How could I connect my 2 cameras and my video projector on one computer ? 

Thanks for your answer

Have a nice day

[Adam B]

Hi Bastien,

Sound like a nice little project.
Yes Qlab can easily do this, we are currently run a show doing 5 live camera feeds to 2 projectors. Total Latency is about 3-4 frames.

Mac Mini hardware might struggle depending on the resolutions your trying to run, but you'll need to test.

I assume your system hardware would be:

• Camera 1 (Input)
• Camera 2 (Input)
• Projector (Output)
• Local Monitor (Output)

Now questions:

• Cameras: Do you camera's have any other way of outputting signal?
• Camera model? (Please don't say GoPro)
  
• Projector: What are all input options?
• Are you intending to project people talking [mouth movement seen]? (this will require low latency)
• What is your intended resolutions of camera input and screen output?
• Budget?
  

Cable runs:
You would be better getting out of HDMI as soon as you can.
You would either need to use a different output signal or convert.
Converting you then need to choose, stay digital, go analogue or use Balan devices. {it is also good to access this step with your input card}

• Digital would be looking at moving to SDI.
  
• Analogue would be dropping to composite.
• Balan would be staying as HDM but converting it and transmitting over CAT6.

Have a look back the the forum lots of recommendations have been previously made and discussed.

I don't want to add to much more and side track with unnecessary info until I have a few more specifics.

Cheers,
Adam

[Bastien Dausse]

Hi Adam,

Thanks a lot for your answers. Sorry to answer you 3 weeks later, but I was working on my project on a place without internet!!! (It still exist).

My camera is a very basic and cheap one (Panasonic HC-V160). It just has AV, mini-HDMI and USB 2. For the projector, I was thinking about using a Epson EB-1970W.

I'm not going to project people talking, it's an acrobatic show, but the lowest latency I have, the better it is!

For the resolution, it's not really important to be in a really good quality. My budget is approximatively 1500 euros, but, the less I can spend, the better it's for me. It's our first show, so we don't have a big budget. I hope it will be enough.

Thanks again for all your answers, I'll think about it and do my research.

(Sorry for my english, I try to do my best!)

Bastien

[Chris Drohan]

Hi,

I thought I'd jump in having come across this and attempted it a fair few times now.

Firstly, when doing this, the power of the Mac Mini is crucial, you'll need something with plenty of both processing power and graphics power.

Next look at the connections you have on your Mac Mini, the latest versions have 2 Thunderbolt and a HDMI for display outs (but you can only use 2 at a time!) but the older generations only have a single thunderbolt and HDMI, so assuming this is the case - you'll need your two outputs to come from these. I recommend you use the HDMI for the local monitor, then use a thunderbolt-VGA or DVI, for the projector.

This then leaves us with getting the cameras into QLab. I recommend (as does figure 53) looking at the Blackmagic range of camera capture cards. They do some excellent hardware which has multiple input types and connections to your Mac. Now you've used your thunderbolt and HMDI connections on the Mac your remaining inputs are USB 3.0. Having 4, this gives you enough to have 2 black magic input cards (I've had good success with the Decklink and Intensity cards).

Finally, working back from the Camera itself, I would recommend using the SD output to the capture card, you won't find yourself losing much quality to the image while keeping a reliable picture.

Hope any of this helps,

Chris

[Adam B]

Hi Bastien,

Sorry for a delaying getting back to you, I was stuck on a bump in and didn't have much time to watch the forum.

Chris's reply is pretty much what I would also suggest.

Hope all is going well.

Cheers,
Adam

[Sandro Flepp]

sorry for answer this old post... can you tell me more about your setup? because it looks absolutely similar like the setup i need to realise. what kind of mac do you use? what kind of cameras?

thx for your answer :)

Sandro