Autodesk 64006-051108-9001 User Guide - Page 194

186 Chapter 8: Encoding DVDs DVD-ROMs are essentially very big, very fast CD-ROMs. Transfer speeds are in the 1 MByte/sec range for 1x, and DVD-ROMs can hold from between 4.7 to 17 GB (gigabytes) of data. However, the higher-capacity DVD-ROM discs are substantially more expensive to press, so many developers keep their production costs lower by using the lower-capacity discs. Even with "only" 4 GB of space, a DVD-ROM could hold about 6 1/2 hours of a 200 KBytes/sec movie. Cleaner encodes MPEG-2, which is the format used for DVD-Video. DVD-Video is another form of DVD that is used for the commercial distribution of prerecorded movies. The discs can be played back on standard set-top and portable DVD players or on computers with DVD-ROM drives. Disc Space If you have a fixed amount of content that you need to fit onto a disc, the length of the video and the size of the disc may become the determining factors of the data rate instead of the speed of the media. Data Rate If you know the space available on the disc and the length of the video, use the following formula to determine the data rate for a movie: datarate = ---d----i--s--c---s---p---a----c---e--videolength where, datarate discspace videolength is the data rate of the final movie in KBytes/sec is the size of the disc in KBytes (see Disc Space formula) is the duration of the video in seconds (see Video Length formula) Disc Space Use this formula to calculate the disc size in KB: discspace = sizeofdisc × 1024 where, discspace sizeofdisc is the size of the disc in KBytes is the size of the disc in MB For example, a CD-ROM is 665,600 KB.