Projecting graphics over live video

[Walter Soyka]

Your video switcher may be able to do this for you, if it has keying capabilities.

We’d need to know more about your setup to help.

Walter Soyka, Principal
Keen Live, Inc.
Presentation, Motion Graphics & Widescreen Design
RenderBreak: A Blog on Innovation in Production

[Andrei Zakow]

Thank you for responding and sorry for my delay.
This project is for a gallery opening and they are renting a projector but I don’t know what kind yet. As for my set up, right now I just have a dvx100a and a macbookpro. The gallery however, will be able to rent or purchase any other necessary equipment that I might need.
Hope that helps.

Thank you.

[Andy Stinton]

When you say graphics do you mean like titling or a lower third?

Andy Stinton
Corporate Video
Live & Stage Events
Business Practices

[Bill Davis]

Andrai,

I think the problem here is one of terminology.

Projecting video is not difficult. A simple video projector will do that.

It’s when you say ” with a static graphic overlayed” that we get confused.

The term “overlay” brings to my mind the old drafting world where one sheet of onionskin paper was literally laid over a base drawing. It was “sort of” a superimposition of one image over the other, but since ink on paper is SUBTRACTIVE with regards to light reflecting off of it you can’t really do that with a video signal.

When you take one video signal and superimpose it on another, the light values are ADDITIVE.

So you can’t take one projector running a video, and add another projector running black on white, or white on black text and have it work like you might expect. The signals will essentially WASH OUT each other.

So I suspect what you’re trying to do is COMBINE the original video signal with another one, so that both are mixed together in a single stream? As you describe it, this is called “title keying” and requires a computer or video switcher with the ability to calculate new pixels from the mathematical combination of the values of the pixels in the two video streams. (the base video and the title super)

In order to help you best, perhaps you could describe the effect you’re trying to get?

Do you want large white type over and obscuring the video? Small black type in a white window on a part of the video picture? Partially transparent type that doesn’t obscure the video beheath it? A box at the top or bottom with scrolling type?

As you can see, there are a lot of variables. Let us know more precisely what you wish to do and perhaps we can guide you to the right tools for doing it.

How much type? Does it need to move?

[Walter Soyka]

Hi Andrei,

Ordinarily, you’d have a video switcher with keying capability, feed the graphics to the switcher as a separate source, and let it add in the graphics for you; it’d also be possible to get a standalone video “logo inserter” that would do the same thing, downstream from your video switcher.

That said, I assume from your posts that your event is pretty straightforward and budget-constrained — one camera, one projector, and nothing else. Please correct me if I am wrong!

So if your question is, “How can I use my Macbook Pro to add a static graphic over live video from my DVX100a?” then the answer is a product like Boinx TV (if you want a well-packaged solution) or Quartz Composer (if you want to create your own, a la Max or Jitter).

That said, there are a couple other considerations.

Redundancy is vital in live events! I always run backups for computer sources on live events. Ideally, if you do use your computer for this, you would have a second computer running the same thing and a video switcher in case your main computer crashes. If you insist on using only one Mac, you should also send video directly from the camera to another input on the projector so you are covered in case the computer crashes.

You haven’t mentioned lighting and audio, and both will be important. I don’t know what you’re considering for audio, but you might want to rent an audio delay unit to compensate for the delay in video due to processing in order to preserve lip sync.

Walter Soyka, Principal
Keen Live, Inc.
Presentation, Motion Graphics & Widescreen Design
RenderBreak: A Blog on Innovation in Production

[Andrei Zakow]

Thank you everyone for your responses, hope you all had a great weekend.

So, the gallery would like a live video feed of people at the show projected onto a screen in realtime. Additionally, there would be a white moving animation of ghost like figures superimposed over the live feed projected onto the screen.

Is this better achieved with a video mixer/switcher or with additional software from a computer? Can FCP do something like this?

The projector being used has multiple in’s from composite to vga.

Hope this is more clear.

Thank you.

[Andrei Zakow]

Thank you everyone for your responses, hope you all had a great weekend.

So, the gallery would like a live video feed of people at the show projected onto a screen in realtime. Additionally, there would be a white moving animation of ghost like figures superimposed over the live feed projected onto the screen.

Is this better achieved with a video mixer/switcher or with additional software from a computer? Can FCP do something like this?

The projector being used has multiple in’s from composite to vga.

Hope this is more clear.

Thank you.

[Walter Soyka]

Thanks for describing what you’re looking for — this helps quite a bit.

FCP will not help you, as it doesn’t handle live video.

Are you familiar at all with compositing? You will need an alpha channel in your footage if you just want to add them to the scene; otherwise, you’d have to try to pull a key, rotoscope, or layer them with another blend mode.

I think either one of the options I mentioned earlier will still do the trick. Try the demo of BoinxTV — it might be just what you need. If you are feeling a little more adventurous, you could write a Quartz Composer patch to accomplish this exact effect. QC has a little bit of a learning curve, but this is a very straightforward patch.

Walter Soyka, Principal
Keen Live, Inc.
Presentation, Motion Graphics & Widescreen Design
RenderBreak: A Blog on Innovation in Production

[Andrei Zakow]

Walter,

Thank you for your help. So I checked out Boinxtv but unfortunately it only seems to run on leopard and not snow leopard yet which I think is the only operating system now available. I’m using Mac OS 10.4.11.
QC as well seems to only run on Leopard.

I tried a demo of Arkaos and I got exactly what I needed but the demo version water marks every so often which I can’t have. I would buy it but I’m not sure I really love it.

I also tried Max/Jitter, which is insane, and I got interesting results but I don’t think I can output through VGA to the projector. It seemed that I could only output through the component/composite cables from my camera(attached via firewire to the computer) to the projector and I can’t have that since I need a composite of images from the camera mixed with an animation sent out to the projector.

Are there any other options?…Software?… I could find a copy of Leopard somewhere I guess and then try Boinxtv…

If I do use software, I would ultimately like something that I can grow with because now I’m so into the possibilities of video art with this mixing process.

Thank you kindly.

[Walter Soyka]

Hi Andrei,

Apple first shipped Quartz Composer in Tiger, so that might still be in play. You’d need to install the “Developer Tools” package from your Mac OS X Tiger disc. Then dig through the “Developer” folder on your hard drive to find Quartz Composer.

Walter Soyka, Principal
Keen Live, Inc.
Presentation, Motion Graphics & Widescreen Design
RenderBreak: A Blog on Innovation in Production