Autodesk 62205-051408-9001 User Guide - Page 102

4 Building Workspaces Time and Timecode Frames (and time) are identified in Combustion in one of two ways: using numbered frames or SMPTE timecode. With numbered frames, each clip is numbered starting at one and increments by one for each successive frame. Timecode is the standard indexing method used for keeping track of video frames. The numbers in a timecode value denote hours, minutes, seconds, and frames (00:00:00:00) elapsed on a videotape. Drop-frame timecode compensates for the small difference between theoretical 30 fps and the realworld NTSC frame rate of 29.97 fps. In drop-frame timecode, the first two frame numbers of every minute are skipped (or dropped). You can identify drop-frame timecode by the semi-colon between the seconds and frames (00:00:00;00). Duration and Timelines All layers, composites, and objects have durations. You can change the duration of a layer by adjusting the in point and out point in the Timeline. The Timeline allows you to position layers and objects in time by providing a visible representation of the duration of the clips in addition to the total duration of the composite. Frame Rate The frame rate is the number of frames that are played back per second of a rendered composite. You can specify a different frame rate for each composite. Typically, the frame rate you assign to a composite depends on the type of rendered output you will generate. For film, use 24 fps. For video, use either 29.97 fps (NTSC) or 25 fps (PAL). If you are creating video for the web, you should use frame rates in the vicinity of 12 fps (lower than that produces jerky video). Cross-Platform Considerations Combustion workspaces are compatible between Mac OS and Windows-based systems. However, you should keep the following in mind when using crossplatform workspaces: • In order for the workspace to find the referenced media, you can place copies of the footage on both systems in the same folder as the workspace file. (You can also use shared folders and public file paths so footage can be accessed over the network.) • When saving the workspace file on a Macintosh system, you must add .cws to the workspace name if you plan to use it in Windows. Windows always automatically adds a 3-character extension when saving files, while the Macintosh does not. Without this file extension, Combustion will not recognize or open the workspace file in Windows. • When you transfer a workspace file from a Windows system to a Macintosh, the file may not have the appropriate icon to associate it with the Combustion application. In this case, the following error message appears when you double-click the file to open it: "The application could not be found." If this happens, launch Combustion first, then choose File | Open Workspace and select the workspace you want to open. For advanced Macintosh users only: you can reassociate any file with Combustion by editing its file type and creator code with any number of shareware or freeware utilities that can perform this operation. The creator code for Combustion is "Cbst" and the type code is "CbWS" (no quotes). These are casesensitive: you must type them exactly as they appear. ▲ If you do not know what creator and type codes are, do not try to do this. You could damage a file beyond repair if you edit the file incorrectly. Contact your system administrator. 86