Autodesk 64006-051108-9001 - Discreet Cleaner - Mac User Manual 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:
where,
datarate
discspace
videolength
Disc Space
Use this formula to calculate the disc size in KB:
where,
discspace
sizeofdisc
For example, a CD-ROM is 665,600 KB.
datarate
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)
discspace
is the size of the disc in KBytes
is the size of the disc in MB
discspace
= ------------------------------ -
videolength
×
sizeofdisc 1024
=