Timeline editing of objects in video

We present a video editing technique based on changing the timelines of individual objects in video, which leaves them in their original places but puts them at different times. This allows the production of object-level slow motion effects, fast motion effects, or even time reversal. This is more flexible than simply applying such effects to whole frames, as new relationships between objects can be created. As we restrict object interactions to the same spatial locations as in the original video, our approach can produce high-quality results using only coarse matting of video objects. Coarse matting can be done efficiently using automatic video object segmentation, avoiding tedious manual matting. To design the output, the user interactively indicates the desired new life spans of objects, and may also change the overall running time of the video. Our method rearranges the timelines of objects in the video whilst applying appropriate object interaction constraints. We demonstrate that, while this editing technique is somewhat restrictive, it still allows many interesting results

Analyzing Barehand Input Mappings for Video Timeline Control and Object Pointing on Smart TVs

Smart TVs are getting popular in recent few years. Given the emerging feature of distant bare hand control, one challenge is how to perform common tasks with this new input modality. Two tasks are discussed in this thesis including video timeline control task and object pointing task. For video timeline control task, we explore CD gain functions to support seeking and scrubbing tasks. We demonstrate that a linear CD gain function performs better comparing with either a constant function or generalised logistic function (GLF). In particular, Linear gain is faster than a GLF and has lower error rate than Constant gain. Furthermore, Linear and GLF gains' average temporal error when targeting a one second interval on a two hour timeline (+/- 5s) is less than one third the error of a Constant gain. For object pointing task, we design five select strategies to compare the performance, including one Positional based mapping, one Rate based mapping, one Positional + Rate based mapping and two Traditional TV remote style mappings. We picked the first three techniques for our user study. Through a series of experiments, we demonstrate that Positional mapping is faster than other mappings when the target is visible but requires many clutches in large targeting spaces. Rate-based mapping is, in contrast, preferred by participants due to its perceived lower effort, despite being slightly harder to learn initially. Tradeoffs in the design of target selection in smart tv displays are discussed

Content-Aware Dynamic Timeline for Video Browsing

When browsing a long video using a traditional timeline slider control, its effectiveness and precision degrade as a video’s length grows. When browsing videos with more frames than pixels in the slider, aside from some frames being inaccessible, scrolling actions cause sudden jumps in a video’s continuity as well as video frames to flash by too fast for one to assess the content. We propose a content-aware dynamic timeline control that is designed to overcome these limitations. Our timeline control decouples video speed and playback speed, and leverages video content analysis to allow salient shots to be presented at an intelligible speed. Our control also takes advantage of previous work on elastic sliders, which allows us to produce an accurate navigation control. ACM Classification: H5.2 [Information interfaces and presentation]

Direct Animation Interfaces : an Interaction Approach to Computer Animation

Creativity tools for digital media have been largely democratised, offering a range from beginner to expert tools. Yet computer animation, the art of instilling life into believable characters and fantastic worlds, is still a highly sophisticated process restricted to the spheres of expert users. This is largely due to the methods employed: in keyframe animation dynamics are indirectly specified over abstract descriptions, while performance animation suffers from inflexibility due to a high technological overhead. The reverse trend in human-computer interaction to make interfaces more direct, intuitive, and natural to use has so far hardly touched the animation world: decades of interaction research have scarcely been linked to research and development of animation techniques. The hypothesis of this work is that an interaction approach to computer animation can inform the design and development of novel animation techniques. Three goals are formulated to illustrate the validity of this thesis. Computer animation methods and interfaces must be embedded in an interaction context. The insights this brings for designing next generation animation tools must be examined and formalised. The practical consequences for the development of motion creation and editing tools must be demonstrated with prototypes that are more direct, efficient, easy-to-learn, and flexible to use. The foundation of the procedure is a conceptual framework in the form of a comprehensive discussion of the state of the art, a design space of interfaces for time-based visual media, and a taxonomy for mappings between user and medium space-time. Based on this, an interaction-centred analysis of computer animation culminates in the concept of direct animation interfaces and guidelines for their design. These guidelines are tested in two point designs for direct input devices. The design, implementation and test of a surface-based performance animation tool takes a system approach, addressing interaction design issues as well as challenges in extending current software architectures to support novel forms of animation control. The second, a performance timing technique, shows how concepts from video browsing can be applied to motion editing for more direct and efficient animation timing