Digital Video Hacks: Tips & Tools for Shooting, Editing, and Sharing (OReillys Hacks Series)
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| You don't need really expensive equipment to create your own 3D video. During the 1950s, there was a 3D craze for moviemakers. People flocked to movie theaters to put on cheap, funny-looking, paperboard glasses with different-colored lenses. Well, the craze is over, but you can still create a movie that requires your viewers to don those silly glasses. To create a 3D movie, you need to choose a technique and become familiar with its strengths and weaknesses. Although there are four common techniques, only two can be used at a reasonable cost: anaglyph and Pulfrich. The other types, polarized and alternating field, are both complicated and expensive to produce (and the glasses aren't cheap, either).
3.14.1. Creating an Anaglyph 3D Movie
Traditional three-dimensional movies, such as Jaws 3D and SpyKids 3D, are created as anaglyphs. Anaglyphs are composed of two images, taken at the same time, at slightly different angles. Basically, the images are composed as if taken from the eyes of a viewer one camera on the left and one camera on the right.
When composed together, color-corrected, and viewed through glasses with one red lens and one blue (or cyan) lens, anaglyphs appear three-dimensional due to the perception of depth. Figure 3-31 shows a pair of glasses for viewing anaglyph images. Figure 3-31. Anaglyph 3D glasses
3.14.1.1. Recording for a 3D effect
To create an anaglyph, you need to capture your video using two cameras. If you are planning on shooting a multicamera-style video, you will need twice as many cameras as you intend to use. For example, if you are planning on doing a three-camera shoot, you will need six cameras total to capture your video to process it as an anaglyph.
If you don't have two videotape cameras, you can still create a 3D video by using two web cameras. Depending on the speed of your computer and the software you use to capture your video, you might need two separate computers to capture each video independently. Figure 3-32 shows a setup using two iSight cameras. Figure 3-32. A two-web-camera setup
When setting up your cameras, attempt to place them about three inches apart from each other. This is intended to mimic the distance between a person's eyes. You can either set up two tripods as closely together as possible, purchase a mounting bar like one offered by Jasper Engineering (http://www.stereoscopy.com/jasper/heavyduty-bar.html; $199 $289), or construct your own mounting bracket. If you plan on capturing close-ups, you might have to angle the cameras inward, in an almost cross-eyed fashion. To make the editing process easier, find a way to synchronize your cameras. You can do this either by setting the cameras to record timecode as the current time of day, or by using a slate [Hack #9]. Also carefully label your tapes, so you can determine the left from right camera angels. 3.14.1.2. Creating the effect
After you have acquired your footage, you need to import it into your editing system and place your footage on your timeline. Place both videos within the same space, so that the videos are stacked in your timeline. Although how you place your footage is up to you, make sure you know which image is from the left camera and which is from the right camera. If you are planning to make your video black and white, completely desaturate both video layers (or simply make them black and white, if your system offers such an easy solution). Also apply any effects you plan on using to your scenes before applying any of the anaglyph effects. Otherwise, you might not get the results you desire. The images for both the left and right cameras need to be composed together, so the top layer needs to be slightly transparent; about 50% should suffice. Otherwise, the footage on the lower layer will never be seen. Here's how to change the opacity of your footage:
Once you have changed the opacity, you need to alter the RGB (Red, Green, Blue) values. To create the 3D effect, you need to remove red from the right camera and remove green/blue from the left camera. Doing so will cause the viewers, when wearing anaglyph glasses, to see the image in a stereo pair thereby creating the illusion of depth. Here's how to alter RGB values:
After you change the RGB values, your image will look a little odd. This look is expected, because you have removed colors from the composition. To finalize your 3D look, attempt to line up your two images so that they appear as closely as possible to be one image. Figure 3-33 shows an image before it is lined up and after. Figure 1-33. Lining up two images to make the effect work
3.14.1.3. Viewing the video
To see the 3D effect, you need a pair of glasses with one red lens and one blue (or cyan) lens. If you don't have a pair lying around the house and you need a pair ASAP, you can make a run to the local bookstore and pick up a 3D children's book (which should include a pair of glasses). If you are willing to wait for them, get a pair for free from http://www.rainbowsymphony.com/freestuff.html. You can also purchase them in bulk from http://www.3dglassesonline.com. Once you have a pair of glasses, viewing your video in 3D is as easy as putting on your glasses and pressing (or clicking) the Play button. 3.14.2. Creating an Pulfrich 3D Movie
You can create a 3D using a single camera by using the Pulfrich effect. Using the Pulfrich effect to create a 3D movie does not require the images to be effected in any way and involves only the movement of the camera or the objects it is recording. In fact, when creating a 3D movie using the Pulfrich effect, you can view your raw footage in 3D! Additionally, viewers who do not wear 3D glasses can still enjoy the video without realizing they are missing anything.
3.14.2.1. Recording the video
Making a video using the Pulfrich effect is easy. You simply need to move the camera horizontally left-to-right or right-to-left. This is essentially a dolly move; however, for the effect to be of use, the movement must be smooth. Figure 3-34 diagrams how a camera should move to create the Pulfrich effect. The fundamental ingredient to the effect is an object's movement in relation to the camera. A simple and fun experiment to experience the Pulfrich effect is to sit in the passenger seat of a car and record the scenery out of your window. Driving at various speeds will provide ample insight to how momentum can affect the Pulfrich effect. If you plan on using this technique, I highly recommend experimenting with it first. 3.14.2.2. Viewing the effect
To view a Pulfrich effect video, you need a pair of glasses with one lens of transparent grey and the other clear. You can create a pair of Pulfrich effect-friendly glasses by simply removing one lens from a pair of sunglasses. Plus, if you wear them while watching a sporting event, such as football, you will probably experience some 3D images. Figure 3-34. The Pulfrich effect, caused by horizontal camera movement |
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