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Video. Using video. Carefully planned, well-executed video clips can make a dramatic difference in a multimedia project Use video only when all other methods (text, still images) are not enough; don’t use it just because it’s possible. Obtaining video clips. Shoot your own clips
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Using video • Carefully planned, well-executed video clips can make a dramatic difference in a multimedia project • Use video only when all other methods (text, still images) are not enough; don’t use it just because it’s possible
Obtaining video clips • Shoot your own clips • Buy footage; this can be a nightmare since the licensing rights and permission may be difficult to obtain • On some projects you have no choice but to pay the price for required footage • Example: Istockphoto
Video compression • Even a small 10-second clip of full-motion video requires transfer of an enormous amount of data in a very short amount of time • One frame of 24-bits requires almost 1MB of computer data, 30 seconds will require a one gigabyte • Full-size, full-motion video requires that the computer deliver data at about 30MB per second • This technological bottleneck is overcome using digital video compression schemes or codecs (coders/decoders)
Video compression • A codec is the algorithm used to compress a video for delivery and then decode it in real-time for fast playback • All popular codecs employ lossy compression algorithms • Popular codecs: MPEG, Divx, RealVideo, DVI/Indeo, Cinepak
Typical filename extensions • avi - Audio Video Interleave • mp4 - MPEG-4 Part 14 or MP4 file format • mkv & mka - Matroska Multimedia Container • mpg & mpeg - Moving Picture Experts Group • flv - Flash Video • wmv, wma & asf - Advanced Systems Format • mov - Apple Quicktime Movie • rm - Real Media File • 3gp - 3GPP Multimedia File • vob + ifo - Video Object & DVD Information File Wikipedia: Comparison of Container Formats http://en.wikipedia.org/wiki/Comparison_of_container_formats
Use of video in multimedia (good video is illustrative) (use static video, near shots) (less than 1 min clips) (video is confirming and creates mental images) (divide long video into clips with interactivity)
Principles of animation • Animation is possible because of a biological phenomenon known as persistence of vision and a psychological phenomenon called phi • An object seen by the human eye remains chemically mapped on the eye’s retina for a brief time after viewing • Combined with the human mind’s need to conceptually complete a perceived action, this makes it possible for a series of images to blend together into a visual illusion of movement
Computer animation • Computer animation programs typically use layers, keyframes and tweening techniques • These methods are commonly used also with traditional animations that are done without computers • You can usually set your own framerate, but the rate at which changes are computed and screens actully refreshed will depend on the power of your display platform and hardware • The smaller the object, the faster it can move
Animation file formats • Some file formats are designed specially for animations; they can be often ported among applications and platforms • Popular animation formats: Director (.dir and .dcr), 3D Studio Max (.max), Windows Audio Video Interleave (.avi), Machintosh Quicktime (.mov), Motion Video (.mpg), Flash (.swf)
Video vs. animation • Video includes something that is real; an animation has no limits • When to choose video, when animation? • http://streams.metropolia.fi/old/optometria/skiaskopia/
Example: • 2D Visualization of nuclear power plant components • 3D visualization of a wood pressing machine
