Storyboard Frame Editing for Cinematic Composition
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Storyboard Frame Editing for Cinematic Composition Scott McDermott Junwei Li William Bares Center for Advanced Computer Studies University of Louisiana at Lafayette Lafayette, LA 70504 USA +1 337 482 6284 sdm1718, jxl0326, [email protected] ABSTRACT STORYBOARD FRAME EDITOR We are developing an intelligent virtual cinematography The storyboard frame editor allows an author to visually interface that can be used to compose sequences of shots and specify how the camera should frame a set of subjects in a automatically evaluate individual shots and transitions, shot (Figure 1). A shot is a continuous sequence of frames reporting possible deviations from widely accepted cinematic filmed by one camera. This editor automatically exports a set composition guidelines. Authors compose shots using a of constraints, which are used by a solver to compute a Storyboard Frame Editor to place subject objects as they satisfactory shot of the subjects in a given 3D scene [1]. should appear in the frame. Then the Storyboard Sequencer is STORYBOARD SEQUENCER used to design shot-to-shot transitions. The storyboard sequencer is used to arrange shots into Keywords cinematic compositions by specifying the possible transitions Animation, Graphical user interfaces between shots. The sequencer can edit either linear or INTRODUCTION branching arrangements of shots. Expert cinematographers have long since used cinematic LINEAR IDIOMS idioms to direct the flow from frame to frame by representing Many film production designers illustrate the progress of common shots such as the establishing shot and two shot of scenes in a film, by drawing a number of storyboard sketches, conversing players [5]. Virtual 3D cinematography systems one for each shot. We have adopted this convention for the adopted idioms to help generate sequences of prototypical sequencer’s linear mode, in which users can edit idioms shots to film actions such as conversations between small whose shots are always presented in the same linear order just groups of virtual players [2, 3, 4]. Our visual interface allows as in motion pictures (Figure 2). authors to quickly create their own idioms with the help of an automated composition assistant. Figure 1. Frame Editor User Interface. Figure 2. Storyboard Sequencer in linear mode. Permission to make digital or hard copies of all or part of this work for BRANCHING IDIOMS personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that The sequencer’s branching idiom mode is used to construct copies bear this notice and the full citation on the first page. To copy idioms in which one shot may transition to two or more other otherwise, or republish, to post on servers or to redistribute to lists, shots (Figure 3). The actual selection of which transition requires prior specific permission and/or a fee. branch to take during an animation is left to the user’s 3D IUI’02, January 13-16, 2002, San Francisco, California, USA. Copyright 2002 ACM 1-58113-459-2/02/0001…$5.00. application program, which imports the idioms and calls upon a constraint solver to position the camera [1]. &URVVLQJWKHOLQH Test if a subject appears to suddenly change direction (Figure 4b). Compute the subject’s view angle relative to the camera in the two frames. This angle is measured in the horizontal ‘ground’ plane and is 0 if the subject directly faces the camera. If the view angles differ in sign, the assistant suggests that the author insert a neutral angle shot of the subject facing towards or away from the camera or change the angle of either shot. -XPS&XW Avoid cut transitions between two frames that do not present a set of subject(s) at significantly different size, position, or view angle (Figure 4c). For each subject in the Figure 3. Storyboard Sequencer in branching idiom mode. first frame, we find its view angle relative to the camera, its size in the frame, and location in the frame and subtract SEQUENCER INTERFACE The Storyboard Sequencer allows authors to combine these from the corresponding values for that subject in the individual frames into a linear (Figure 2) or branching idiom next frame. Report failure if the absolute values of any of (Figure 3). In either mode, the user can add and manipulate these calculations fall below the user-specified thresholds. shots or edit a shot in the Frame Editor by selecting it by CONCLUSION browsing the thumbnail images of the frames. In the We plan to extend the composition assistant to implement branching mode, the sequencer is divided into two additional cinematic and photographic composition workspaces, with sequences on the left and shots on the right. guidelines and evaluate its performance in authoring camera Both shots and sequences can have various transition links, shots for several short animated 3D films. represented by arrows, between other shots or sequences. ACKNOWLEDGMENTS COMPOSITION ASSISTANT Thanks to Christina Boudreaux and Somying Thainimit for The Storyboard Sequencer includes an intelligent assistant help with the frame editor and constraint solver, and also to that may be invoked to evaluate individual frames and the Louisiana Board of Regents for support under Board of transitions to suggest improvements to the composition. Regents Support Fund contract (1999-2002)-RD-A-48. Photographic/Per Frame REFERENCES Examine a subject’s placement, size, and view angle relative 1. Bares, William, Scott McDermott, Christina Boudreaux, to the camera in an individual shot to check if a selected and Somying Thainimit. Virtual 3D Camera Composition photographic composition guideline is satisfied [6, 7]. from Frame Constraints. In ACM Multimedia 2000, 5XOHRI7KLUGV October 30th to November 4th, Los Angeles, California, Suggests that subjects appear at or near the intersection of a pages 177-186. pair of horizontal and vertical lines that divide the frame into 2. Drucker, Steven and David Zeltzer. 1995. CAMDROID: A nine equal parts (Figure 4a). This check is satisfied if the System for Implementing Intelligent Camera Control. In bounding rectangle of each subject covers one of these four 1995 Symposium on Interactive 3D Graphics, pages 139- intersection points of the two vertical and horizontal lines. 144, 1995. Cinematic/Per Transition 3. Karp, Peter, and Steven Feiner. 1993. Automated Examine the visual continuity of the pair of frames on each Presentation Planning of Animation Using Task end of a transition [5, 6], or a series of transitions. Decomposition with Heuristic Reasoning. In Graphics Interface ‘93, 1993, pages 118-126. 4. Li-wei He, Michael F. Cohen, and David H. Salesin. 1996. The virtual cinematographer: A paradigm for automatic realtime camera control and directing. In Computer Graphics (Proceedings of SIGGRAPH ‘96), Figure 4b. Crossing the line 1996, pages 217-224. 5. Mascelli, Joseph. The Five C’s of Cinematography. Silman-James Press, Los Angeles, California, 1965. 6. Millerson, Gerald. 1994. Video Camera Techniques. Focal Press, Oxford, England, 1994. 7. Peterson, Bryan. Learning to See Creatively. Watson- Figure 4a. Rule of Thirds Guptill, New York, New York, 1988. Figure 4c. Jump cut .