HINTS FOR MAKING GOOD VIDEOS
Introduction
Video is a great way for showing reviewers the look and feel of your application. Much of the work at IUI involves highly interactive applications and examples that are difficult to capture using words and static images. To misquote the cliché, if a picture is worth a thousand words, then a good video can be worth many more still.
IUI98 videos should run no longer than 10 minutes.
Guidelines
The guidelines discussed below were originally developed for CHI video submissions, which are included in a "video proceedings" and must therefore be completely self-explanatory and meet very high standards of production quality. Videos for presentation with a talk should be clearly visible and easy for the audience to follow, but need not meet such high standards of craft (but the closer, the better!). Moreover, if you are submitting a video only for the use of reviewers, you needn't worry so much about production quality and pacing as you would if you intend to show the video at the conference. In any case, following these time-tested suggestions will help you produce a better video with less effort.
Before Taping Begins
Before taping begins, have a detailed script of the video that has been thoroughly rehearsed. Videos require much more planning and preparation than most people think. Find someone who doesn't understand what you do, sit them down and give your demo to them before the camera arrives. It's good practice in speaking and helps to clarify the delivery of your ideas. If your demo involves a larger group of people, it will be especially important to have the major scripting and production bugs worked out beforehand.
There's no need to hire professional actors to appear in your video. (However, professional readers may be appropriate for the audio, see below.) Usually the most realistic and convincing advocate of an idea is the person responsible for the research. However, make sure people who appear on camera speak naturally, and don't look like they are reading. Remember that the value of video is as a way of demonstrating things, so keep talking heads to a minimum unless they are an intrinsic part of the event or process being described.
Pacing
The video medium is different from either a lecture or demonstration. The pacing of a videotape presentation must be appropriate for concentrated presentation through a TV monitor. Too slow a pace is as common as too fast. A recording of a live demo will appear too slow. A large number of jump cuts (abrupt change of image) tends to create too fast a pace.
Exposition and Presentation
In contrast to the CHI videotapes which must stand alone and be understandable to viewers who are not familiar with the subject, IUI videotapes are intended to accompany a paper. Therefore it's not necessary to start with an extensive introduction explaining the goals and context of the work.
The exposition style of your videotape presentation will greatly affect its impact. Use the multiple modes of communication that are available simultaneously in videotape. Always explain (briefly perhaps) what is about to happen or what is most interesting. Tell the viewer where to look and what to look for. You might speak aloud the directions to the camera operator, such as ``if you zoom in on the top right corner of the display'' which will help the viewer orient themselves. Display screens have few natural navigation aids. Make your point once, and make it effectively; avoid being repetitious.
Seek variety of image: switch between face, screen, hands, and slides to keep the viewer's interest. Always start out with an establishing shot, which shows the context of the subject and/or group. This might be a wide shot of the group in a meeting room, a split-screen shot of users in different locations, a wide shot of a meeting participant at the computer, or of the entire computer screen. This helps the viewer stay oriented. Periodically return to an establishing shot to keep the viewer from getting confused.
Each shot should be visually well-composed. Avoid having the subject in the exact middle of the screen. Pay attention to the background and colors; the eye is drawn to the most brightly colored part of the scene. Make the lightest and brightest part be the point of interest. Carefully consider lighting and make sure that there are no ghoulish shadows on faces (a common occurrence with overhead lighting) and no dramatic shadows on walls.
Do not overuse panning, zooming and other moving shots. Begin and end each moving shot with a static shot. Avoid visual distractions, such as idly moving the mouse. Fades to black can be used as transitions between scenes, but they should not be overused. A full screen fade usually indicates a change in subject, time or place, and can be confusing when used elsewhere.
Equipment
The final production quality of a video depends both on the quality of the equipment and the training and experience of the video maker. If you have access to a high-quality production studio and trained personnel, use them. However, production quality can be achieved with the commercial equipment found in most universities and companies. The guidelines below are intended for researchers who have access to such equipment, but little experience in making videos.
Camera Basics
Maintain the quality of the original recording medium throughout the editing process. Shoot black and white displays with a black and white camera or only one gun of a color camera, usually green.
Keeping the camera stable and level is vital. Use a tripod, whenever possible. Remember that camera jiggles are more apparent in telephoto shots; take extra care in zooms and close-ups.
Avoid using different sources of lights when shooting, as it will throw off your colors. For example, avoid taping in a room with both natural and artificial light sources. The white balance setting adjusts the camera to your lighting. When setting, focus the camera on the color that you want to be filmed as white. This could be a sheet of white paper or the whitest color in the scene, depending on the effect you want. Avoid having too much white in a scene because it will make all your other colors too dark. Monitor your video levels. White levels should be at 100 units, and black levels should have a pedestal of 5 to 7.5 units. If possible, include 30 seconds of color bars and tone at the beginning of the tape. The color bars must be generated by the camera or editing equipment. Color bars copied from another tape are worse than none at all.
You will need to use a TV in addition to the view-finder of the camera during taping. It is impossible to tell if the shots are correct from just the little view-finder. Remember that the final picture will not be as clear as the picture in the monitor, so zoom in closer than might seem necessary, and make sure that no important parts are at the edge of the picture.
Tape Format
IUI98 is able to accept only NTSC (i.e. North American standard signal) VHS format tapes. Use the best quality VHS tape you can obtain.
Video quality decreases markedly with each "generation," that is, each time a tape is copied. Hence, you may want to use a higher resolution tape for your original recording. From highest to lowest quality, the formats are: 1-inch, Beta SP, 3/4 inch U-matic, Hi-8mm, and Super VHS.
Editing
To minimize loss of quality, you should be sure to edit your original raw footage directly onto the final master tape. A good idea is to do a rough edit from the original tape onto a working copy. Write down all the "edit points," that is, the times in seconds or, better, frame numbers at which to start and end a particular extraction from the raw footage tape(s). Then do a good edit in which you copy from the raw footage to your final master.
Audio
Audio quality is as important as image quality to the overall impact of your video. Try to avoid recording the noise of computer fans and disks. Therefore, it is generally better to record the audio after the video by doing a voice-over in a studio or other quiet room. With a voice-over, you watch the video and record the sound that explains what is happening. Make sure that the discussion is synchronized with the action on the screen. If you have introductory ``talking heads,'' try to do these with the computer off, or with the microphones arranged so that the computer noise is not picked up. Another motivation for doing a voice-over afterwards is that the person operating the computer can concentrate on the demo and go as fast as possible without awkward pauses while he or she thinks about what to say next.
Many successful videos use trained readers for the audio, which you can find by calling acting schools or radio stations. Alternatively, the researchers may do the voice-over after the demo is complete.
If it is important to hear key clicks or computer audio output (beeps), record these on a separate audio track, and mix them with the voice-over in the editing studio. Similarly, if you are adding music to the video, this can go on a separate track, so it will be easy to fade out music when narration begins, etc.
Taping Computer Screens
Because of incompatibilities of resolution, refresh rate, and interlacing, it is often difficult to get good shots of computer screens on video. Two ways to capture the image: by pointing a camera at the screen, or using a scan converter or video encoder to translate the computer's signal directly to an NTSC signal or videotape. You will probably need to experiment to find the best way of capturing screen images on video.
Most people will film the screen with a camera. In this case, darken the room to enhance contrast, and set your white balance to match the white of the screen. Position your camera to avoid rhomboidal windows from the curved face of the display. You will have to pan around the screen to show different parts, because the video will usually not show the entire display in sufficient resolution to read text and see the graphics. If you have problems with one camera, you might consider borrowing or renting different cameras to see if you can obtain better results when shooting from the screen.
Try to find a display that has a refresh rate that is compatible or synchronized with the video camera rate of 30 frames per second. Most displays are not, so you will get a crawling refresh line on the tape. In this case, try to wait until it is not visible before each video segment. If there is a continuous beating or flashing on the video, this means that the refresh rates are completely incompatible, and you should probably not make a video of that screen.
The best screen from which to film is an active matrix LCD, since this has no refresh cycle. Be sure to film in a darkened room so that the colors will be bright.
If you have hardware that converts your computer signal to NTSC, you can record directly from your computer to tape. A major problem with this is that single pixel horizontal lines will flicker badly (in fact, all odd number width horizontal lines will flicker somewhat). If your display is color, limit color saturation to 75 to 80% and choose hues carefully, especially reds, to avoid exceeding the NTSC color bandwidth.
Final Thoughts
Anyone who has done video editing and post-production knows that it is a surprisingly time consuming business. However, it's garbage-in garbage-out, and if you don't have good content or message, the best video editing in the world won't help it that much. So, make sure that you thoroughly "proof read" your video. The time will be well spent, and it will probably still only require a fraction of the time that you have to spend anyway on video production.
So, how does one "proof read" a videotape? You can start off by testing your script with colleagues and friends. Is it interesting and understandable? Next you may want to storyboard your video. Do the cuts and transitions make sense to people, can then visualize how it will look? As well as being useful for usability testing, the storyboard should be an important part of your planning process. Next you should do rough cuts of the video. Do people want to see more talking head shots or less? Is the demo clear? Is the pace too fast or too slow? Are there any particular usability problems with specific segments of the video?
Making a video is hard work, but as any attendee of CHI or SIGGRAPH will tell you, a good video is worth its weight in gold.
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