This section contains guidelines and advice for those who are new to video production, particularly in creating videos for CHI. The following suggestions will help you produce a successful Video Figure or Video Preview of your work. None of the following suggestions are required reading.
Important: Please review the Technical Requirements and Guidelines for Videos at CHI to make sure that your video complies with our technical requirements for video submissions.
Organization and Structure
There are many ways to organize a video presentation, just as there are many ways to write prose. You should use that video to tell a (micro) story and present the research in a way that contributes to this goal. Your video should be understandable by itself; you should not assume that the viewer has read your printed submission. Your video should also be understandable to viewers who are not familiar with the subject. Therefore, most videos will need a short introduction explaining the goals and context of the work, as well as the problems or issues being addressed.
It is generally not a good idea to simply show all the features of your system; you should identify what is novel and interesting. Always clearly state the status of what is being shown. If you are simulating any aspect of the system, be sure to mention this.
Videos require much more planning and preparation than most people think. Before recording begins, prepare a detailed script of the video, including a written version of any voiceover text at each scene. A common and often effective strategy for videos that use voice narration is to record the entire narration at a comfortable pace, leaving gaps in the audio for important visual transitions, and fit the video accordingly. This is not how one would record a feature film, but it’s a very effective strategy for research videos that can simplify the process.
Once you’ve written a voiceover script, you can start off by testing your script with colleagues and friends, just like you were practicing a talk. Is it interesting and understandable? Incorporate their feedback before you start storyboarding. Next you may want to storyboard your video. Do the cuts and transitions make sense; can you visualize how it will look? As well as being useful for usability testing, the storyboard should be an important part of your planning process.
Exposition and Presentation
The expository style of your video presentation will greatly affect its impact. Use both video and audio. Always explain what is about to happen or what is most interesting: as the narrator, tell the viewer where to look and what to look for. Visual aids, such as callouts, annotations and captions, can help orient the viewer. Make your point once, and make it effectively; avoid being repetitive.
When appropriate, seek a variety of images: switch between face, screen, hands, and slides to keep the viewer’s interest. If possible, 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 prevent viewer confusion.
Pay attention to the background and colors; the eye is drawn to the most brightly colored part of the scene; make sure the brightest point is the point of interest. Carefully consider lighting and make sure that there are no distracting shadows, especially on faces (a common occurrence with overhead lighting).
Avoid visual distractions, such as idly moving the mouse in a screen-captured video. 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.
Video is different from a lecture or a demonstration. A recording of a live demonstration will often appear too slow. A large number of sudden cuts may create too fast a pace. And please remember that your digital video will be accessed by an international audience, so speak clearly and more slowly than is natural to successfully convey your message.
Record in the highest possible quality and resolution, even though you will compress the final video. Maintain the quality of the original recording throughout the editing process; leave compression to the last step.
Keeping the camera stable and level is vital. Tripods are a low-cost way to get the most out of your camera; use a tripod whenever possible. Remember that camera jiggles are more apparent in telephoto shots; take extra care in zooms and close-ups. Contemporary hi-definition web-cameras are suitable for over-the-shoulder shoots.
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 elements are at the edge of the picture.
Lighting makes a huge difference in perceived quality. For indoor recordings, if you have access to a diffuse light source, use it. Avoid overhead lights that cast shadows in the scene, and avoid light sources that are directly visible to the camera. Lighting for video is closely related to lighting for photography, so if you have friends who are hobbyist photographers, ask them for advice on how they might light a scene.
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. Choose a quiet room, or a studio if you can, to record any audio material. If it is important to hear key clicks or computer audio output (beeps), record these on an audio track separate from the voice-over. If needed, audio editing tools like Audacity include a filter to eliminate background noise.
You can add a voice-over audio track to explain what is happening in the video. Make sure that the discussion is synchronized with the action on the screen. Usually the most realistic and convincing advocate of an idea is the person responsible for the work being reported. However, you may wish to use someone with a very clear and understandable voice. A professional actor is not necessary; a friend or a trained reader could do it. We recommend that you not use a computer-generated voice as generated by reader applications. Prepare a detailed script of the video and rehearse it thoroughly, in front of others if possible. This will help not only the delivery but also the clarity of your ideas.
If you are adding music to the video, place it on a separate track, so it will be easy to fade out music when the narration or the sound made by the system begins. You can assemble and mix this track in audio-editing tools such as Audacity.
A decent-quality microphone will improve the recording quality relative to a typical computer microphone. A large-diaphragm condenser microphone will generally be best for recording the voiceover track, and nearly any university A/V expert or hobbyist musician will have one; borrow one if you can. Even if you choose to buy a microphone, you don’t need to spend hundreds of dollars to get a quality condenser microphone; the cheapest large-diaphragm condenser microphone you can find will likely provide a huge benefit in audio quality relative to your desktop, laptop, or phone microphone.
Avoid holding a microphone in your hand while recording; support it with a microphone stand. A hand-held microphone will inevitably lead to uneven volume in the recording.
Recording Computer Screens
Because of incompatibilities of resolution, refresh rate, and interlacing, it can be difficult to get good shots of computer screens on video. Using a flat-panel LCD video monitor often leads to best results when filming a computer screen. Use a resolution that lets you capture text, lines, colors and animations accurately.
Other ways to capture a screen is using screen-capturing software. For Windows users, Camtasia, Camstudio, and MS Expression Encoder are known to produce acceptable screen captures. For OSX, the Quicktime player already has a Screen Recording feature.
If you are using screen capture software, make sure that it is able to capture the screen at a satisfactory frame rate and does not affect the performance of your application. Most software can capture the whole screen or a specific area such as a window. Since performance is often affected by the size of the area being captured, you should try focusing the capture on the area of interest. This will also reduce the artifacts if you later compress and rescale the image. Finally, remember that screen capture only captures the screen: you may want to add wider shots taken with a camcorder to show the user interacting with the system; you should also consider adding click sounds when the user clicks the mouse to make such interactions more explicit (some capture software can do that automatically).
Once you have a draft of the video, please test your video for usability. Do people want to see more talking head shots or fewer? Is the illustration of your material clear? Is the pace too fast or too slow? Are there any particular usability problems with specific segments of the video?
Raw analog or digital footage can be 1 gigabyte per minute in data size. Editing digital video generally requires two times more disk space than the video itself. Choose what you want to preserve carefully when editing, and compress your video as a final step.
Before submitting the video, you should try playing it with a variety of video-reading software and a variety of computers.