Flat Rock Playhouse’s production of Buddy Holly marked one of the Biggest projection heavy shows I have been a part of to date. When preparing for this production our Director had a wonderful idea to charge the lack luster script with a little more interest. He wanted to film the voice overs and project recorded video using a rear projection screen above the onstage actors.  Easy in theory. It did offer a number of issues…

Through this idea, there happened to be a couple of scenes where the recorded video was spread into the onstage dialoge. This required precise timing that could change on a show to show basis. The dialoge in the filmed video was integral to the show. If the video system crashed it would bring the show to a screeching halt and leave the onstage actors helpless. There were a number of things that acted agains us. So, I covered my bases. This is how.

Recorded video interacting with Onstage Actors.

First, we wanted the quality of the film to match what was shot and edited. Second, the video was changed to black & white in post so I knew soft grays and deeper blacks were extremely important. Also, video can only go as black as your projection surface will allow. This only added to my reservation to decrease the quality, and therefore the file size, of the video. Meaning I had my reservations exporting to lower pixel dimensions and less bit depth and therefore lowering file size and upping our Mac Pro’s ability to play the clips.

Quick Notes: The major reason our mac pro had difficulty running the video was because it was pushing video to three projectors over (by the end of the tech process and the many changes) two different video cards.

Another Quick Note: Although the filmed footage ended up in black and white, it sill had to be a color film because of a border and frame added in post that needed to match what the lighting designer was doing with the surrounding wall. Plus it wasn’t true black and white, more of a monochrome….

The Backup System

The second thing that offered quite the challenge was a backup system. We knew the show would at least go on if there was no video, but if the embedded audio went away we were up shits creek without a paddle. There are a number of ways to solve this problem. But on a tight budget; only one. We explored using MIDI Show Control to continuously fire a second machine running cue lab and the audio cues. Then tho sound board opp would simply bring up the fader if the system crashed… maybe a one second delay in the show, minus video. This, of course, requires some hardware; a second machine, a USB MIDI interface, some cable, and a rock solid set up. Because of the expense associated  with acquiring a USB MIDI interface for each machine we decided to go with a free program called IP MIDI. This program is great, but has one fall back; it requires an active and working wired network. In our mind, this was one more thing to go wrong. So, instead we jimmy rigged a backup system: a second machine sitting right next to the projections opp running an audio only version of the show. Thankfully we never had to use it. It was a bad idea.

 

Edge blending using a rear projection screen and two projectors.

Edge blending is always a pain. It doesn’t matter who or where you are. If you have any interest im making the images and video designed on a computer look good on a blended screen then it simply takes time. There are a number of variables that act agains you. Keystone, lens shift, the surface the projectors are sitting one, movement of the screen… etc. But the biggest (and simply impassible if you dont have the right equipment) is the image manipulation required to overlap both screens. This, interestingly, can be completely bypassed by using a separate computer for each projector.

When two projectors are attached to the same computer, the video card puts them right next to each other. In other words, the computer/video card has no idea the screens actually overlap each other. So the same image information is projected to two different parts of the screen, resulting in a projected image like the one below.

I know of three ways to solve this. The first way is to procure a computer per projector and use custom geometry and the projectors native edge blending properties to create a complete image. Of course, this is generally out of the question for most theaters. The knowhow, cost and time required to program and set up this type of system generally turns people away. The second preferred way is to get a video card that can compensate for the overlapped area. These video cards are expensive and not worth every dime. And, its rare that a theatre can afford such luxuries. The third way, and the way we did for “The Buddy Holly Story,” was to line the projectors up so precies the the edge of one projectors throw was right next to the others.

You might be asking what is wrong with this idea. If thats the way to video card sees it, and the native way a computer can control them, then why not let this be the standard? The answer is simple. IF you can get the projectors and screen to stay still (in our set up a pixel ended up being 3/32″ of an inch, and a one pixel wide black line in the middle of the image was completely noticeable) and IF you have someone that can check on this on a recular basis and IF there is not dancing on the same floor as the projectos are sitting (if the building shakes the projectors shake) then all you have to worry about is the viewing angle of the screen. I’ll write a post about that later.

 

Rock solid control and video delivery.

As I mentioned before the video was integral to the show, therefore it could not fail. Without video there was not show.

At the playhouse we use software called QLab. QLab is a pretty amazing show control software that allows for a large number of screens, unlimited que’s (video and audio), custom geometry, midi inputs, etc. With all of these options it wont surprise you to know that this is very close to the best show control software available. However, to use all of these options it does require some serious computing power. Power that we could not muster, even with a suped up MacPro.

To ensure the system was rock solid we, unfortunately, were forced to limit the bit rate of all video spanning the two projectors, scaled down the video to half its size and had to run the spanned video from one video card to limit the processing power needed. One video card means that when output video goes down, so does the other. Unfortunately the MacPro does not come with a duel display video card, so we had to upgrade. The new card required more cooling and extra power. (This was not something we had to deal with, however if we were to add anything else in the computer, aside from the video card, we would’ve had to upgrade the power and cooling system.)

These compromises meant video that didn’t look as good, but did run rather well. With this system we were able to complete a four week run without fail, however, it was not the show we wanted.

To get the show we wanted we would’ve had to re-think the system from the ground up. Fortunately, the new system would have cost less, however, the knowhow, set up time and programming time is significantly more. Especially if its a system that has not been used before.  Unfortunately we were already all in with the current system. The new system, the one that will allow for the look that we want and offer more control over the video still uses QLab. Basically a master machine firing que’s over a midi patch to slave computers sitting next to the projectors. One computer per projector. This also enables us to place a projector wherever we want… just as long as it has a network cable next to it.

I’ll do a write up about our new system once I have had a chance to play with it.