1. School of Computer Science & Information Technology G6DPMM - Lecture 15 Media Design III – Video & Animation

2. Perception of Video Changes in sensory input tend to be instantly noticeable Changes in sensory input tend to be instantly noticeable Changes in background sound (e.g. cessation) Changes in background sound (e.g. cessation) Unexpected movement Unexpected movement Motion in peripheral vision Motion in peripheral vision Fundamental biological imperative Fundamental biological imperative Danger Danger Opportunity Opportunity Motion is the strongest such imperative Motion is the strongest such imperative Video is both effective and has a high cognitive cost Video is both effective and has a high cognitive cost

3. Change & Movement Change Change A sensory property becomes different over time A sensory property becomes different over time For example –visual properties For example –visual properties Colour, size, position Colour, size, position Movement Movement A type of change involving position A type of change involving position Animation Animation A type of movement that is synthetic (e.g. generated by computer, cell drawing, etc.) A type of movement that is synthetic (e.g. generated by computer, cell drawing, etc.)

4. Increasing use of Video Video is becoming increasingly used in multimedia Video is becoming increasingly used in multimedia Technically more feasible (i.e. cheaper) Technically more feasible (i.e. cheaper) Increasing bandwidth on networks Increasing bandwidth on networks This may or may not be a good thing! This may or may not be a good thing! Very powerful media for conveying concepts Very powerful media for conveying concepts Is it being used for conveying useful concept? Is it being used for conveying useful concept? The (cognitive) power of video is the danger! The (cognitive) power of video is the danger! Video grabs attention like no other media Video grabs attention like no other media If the message is trivial or mundane this is a very bad thing! If the message is trivial or mundane this is a very bad thing!

5. Video Abuse Video is becoming increasingly used in multimedia Video is becoming increasingly used in multimedia Technically more feasible (i.e. cheaper) Technically more feasible (i.e. cheaper) Increasing bandwidth on networks Increasing bandwidth on networks This may or may not be a good thing! This may or may not be a good thing! Very powerful media for conveying concepts Very powerful media for conveying concepts Is it being used for conveying useful concept? Is it being used for conveying useful concept? The (cognitive) power of video is the danger! The (cognitive) power of video is the danger! Video grabs attention like no other media Video grabs attention like no other media If the message is trivial or mundane this is a very bad thing! If the message is trivial or mundane this is a very bad thing! Appropriate video Appropriate video Only use if there is no other way to convey the message Only use if there is no other way to convey the message Use video sparingly Use video sparingly

6. Data budget / experience trade-off High quality is desirable High quality is desirable BUT – data budget implications BUT – data budget implications Length of clip Length of clip Clarity of image Clarity of image Resolution of image (i.e. size) Resolution of image (i.e. size) Frame rate Frame rate How high quality to you need? How high quality to you need? Depends upon application Depends upon application Some (e.g. medical) need very high quality Some (e.g. medical) need very high quality Medium quality might be acceptable (sports) Medium quality might be acceptable (sports) Lower quality might be acceptable (e.g. talking head) Lower quality might be acceptable (e.g. talking head)

7. Data budget / experience trade-off High quality is desirable High quality is desirable BUT – data budget implications BUT – data budget implications Length of clip Length of clip Clarity of image Clarity of image Resolution of image (i.e. size) Resolution of image (i.e. size) Frame rate Frame rate How high quality to you need? How high quality to you need? Depends upon application Depends upon application Some (e.g. medical) need very high quality Some (e.g. medical) need very high quality Medium quality might be acceptable (sports) Medium quality might be acceptable (sports) Lower quality might be acceptable (e.g. talking head) Lower quality might be acceptable (e.g. talking head)

8. Placing the video Placing video on screen Placing video on screen Provide video with its own area on screen Provide video with its own area on screen Provide video with its own video playing context Provide video with its own video playing context The context may be the entire screen The context may be the entire screen Linking to video Linking to video Don’t hide links Don’t hide links Make it obvious that it is a video link Make it obvious that it is a video link Video context (1) Video context (2)

9. Video & Narrative Videos have their own pace Videos have their own pace To a greater or lesser extent, control is removed from the user To a greater or lesser extent, control is removed from the user This can disrupt narrative This can disrupt narrative Done deliberately Done deliberately Takes over the users attention to focus on an important point Takes over the users attention to focus on an important point Done badly Done badly User feels disempowered and frustrated User feels disempowered and frustrated Leads to annoyance or loss of attention Leads to annoyance or loss of attention

10. Video Controls Important for empowering a user Important for empowering a user BUT – too many inappropriate controls are confusing BUT – too many inappropriate controls are confusing A common mistake is to include all possible controls A common mistake is to include all possible controls What is the users motivation for watching the video? What is the users motivation for watching the video? Automatic play Automatic play In page video – very bad practice (user out of control) In page video – very bad practice (user out of control) Unique context – might be acceptable, depending upon complexity of context Unique context – might be acceptable, depending upon complexity of context Play / Stop button Play / Stop button Addresses the problem of automatic play Addresses the problem of automatic play Provides a quick exit route Provides a quick exit route

11. Within video navigation Full video controls Full video controls Slow motion (varying speeds) Slow motion (varying speeds) Rewind (varying speeds) Rewind (varying speeds) Reverse (NB problems with some codecs) Reverse (NB problems with some codecs) Single frame step Single frame step Frame numbers / jump Frame numbers / jump Chapter-based navigation Chapter-based navigation User defined bookmarks User defined bookmarks Are these needed? Are these needed? Some applications (e.g. sports) need more than play/stop Some applications (e.g. sports) need more than play/stop Long clips have different requirements from short ones Long clips have different requirements from short ones Probably technical multimedia applications (e.g. video editing) need this full range Probably technical multimedia applications (e.g. video editing) need this full range Controls don’t need to be permanent (e.g. advanced mode) Controls don’t need to be permanent (e.g. advanced mode)

12. Link Labelling & Interruption Never force users to watch video they don’t want Never force users to watch video they don’t want The longer the clip the more important this rule is The longer the clip the more important this rule is Design dilemma – link labelling can interrupt narrative flow Design dilemma – link labelling can interrupt narrative flow Either: Either: Warn the user about a video before they view it (link labelling) Warn the user about a video before they view it (link labelling)or Allow an easy way out of the video (interruption) Allow an easy way out of the video (interruption)

13. Minimize video usage Break large clips down into small clips Break large clips down into small clips Must be under full control Must be under full control Preview clips may be useful Preview clips may be useful Does this affect narrative flow? Does this affect narrative flow? Video introduction Video introduction Video “scene-setting” sequence followed by other media Video “scene-setting” sequence followed by other media Audio only Audio only Voice is often as effective as a “talking head” Voice is often as effective as a “talking head” Images and Audio Images and Audio Commented slideshow Commented slideshow “Foreign correspondent” style “Foreign correspondent” style Audio speech with still picture of person speaking Audio speech with still picture of person speaking Various other media as needed Various other media as needed

14. Animation in Design Types of animation Types of animation Moving still objects along pre-defined paths Moving still objects along pre-defined paths Changing shapes of objects Changing shapes of objects “tweening” “tweening” Frame (cell) based animation Frame (cell) based animation Animating wire-frame models Animating wire-frame models Representation of movement Representation of movement Movement may be hinted at – even in still images Movement may be hinted at – even in still images

15. Use of Animation Most of the guidelines for using video apply Most of the guidelines for using video apply Animation is cognitively powerful Animation is cognitively powerful Use sparingly and with good reason Use sparingly and with good reason Beware of animation in cheap clip-art libraries Beware of animation in cheap clip-art libraries Putting free animated gifs on your web pages is usually a very bad mistake! Putting free animated gifs on your web pages is usually a very bad mistake! Because movement is powerful very subtle animations are often the most effective Because movement is powerful very subtle animations are often the most effective

16. Cartoon Physics Animation in multimedia is about communicating concepts, not modelling the world Animation in multimedia is about communicating concepts, not modelling the world Animations should behave the way people think that they will – not the way they really will Animations should behave the way people think that they will – not the way they really will Cartoons exaggerate this behaviour – this sort of exaggeration can be useful in making a point Cartoons exaggerate this behaviour – this sort of exaggeration can be useful in making a point