Adobe 22030000 User Guide - Page 32

ENCORE CS3 28 User Guide 4 If you want to create a dual-sided disc, specify which side this project is for. 5 Close the Build panel and save the project. See also "Check the space remaining on your disc" on page 28 Check the space remaining on your disc The Build panel displays the available space and the used space for the specified disc size during the authoring process. The display conveys size information only and has no bearing on quality. Encore calculates the free space using the transcoding data rate (whether it was set automatically or manually). It then combines this estimated bit rate with the actual bit rate of any transcoded clips and, based on the disc size, calculates the space remaining on your disc. When transcoding assets, Encore attempts to maintain the highest quality (highest data rate) for the amount of video in the project. If you continue to add video to a project, the program lowers the video data rate to squeeze in the additional content. Encore will warn you if quality dips below a certain level once you build the project or run Check Project. For more information, see "About transcoding" on page 51. ❖ Choose Window > Build to display the Build panel, and scroll down to the Disc Info section. Encore displays the amounts of used video space, free space, and space used for ROM content. Respectively, the "thermometer" graphic uses blue, white, and green colors to show the amounts. Asset types and amounts Of all the content types, the video portion occupies the most disc space. Depending on the data rate, 1 minute of standard-definition video for DVD projects can occupy up to 73.5 MB, at a rate of 9.8 megabits per second (Mbps). One minute of high-definition video for a Blu-ray project can occupy from 270 to 405 MB (using rates of 36 Mbps and 54 Mbps). One minute of compressed audio, on the other hand, occupies only 11.5 MB. Still menus are negligible in terms of size. (See "Average asset size" on page 30.) The amount of video in a project directly affects the optimal data rate. You need an accurate tally of the amount of video in a project to develop a bit budget and to choose a disc size. If the project contains 1 hour of video, for example, it can be transcoded at twice the data rate as a project with 2 hours of video content. Although the video content in each project occupies the same amount of disc space, the quality of the hour-long video will be superior (though not necessarily by a factor of 2). See also "About transcoding" on page 51 Data rates Data rates, usually expressed in Mbps (megabits per second, or 1,000,000 bits per second), specify the amount of data contained in an asset stream and directly affect the quality of video. The data rate is used during transcoding to compress the asset. For video assets, the Encore transcode presets use data rates ranging from 15 to 40 Mbps for Bluray projects and from 4 to 9 Mbps for DVD projects. You can edit the presets' data rates, but you cannot exceed 40 Mbps for Blu-ray projects or 9.0 Mbps for DVD projects, nor can you go below the Encore minimum data rate of 2.0 Mbps. Typical data rates for video range between 4 and 6 Mbps. If bit budgeting targets a data rate less than 6 Mbps, consider using variable bit rate (VBR) encoding. For more information about VBR, see "Calculate a bit budget" on page 29. For more information about transcoding, see "About transcoding" on page 51.