Apple Final Cut Pro 5 - Manual (Page 1702)

Appendix A Video Formats 351
V
Storage Medium
Video—especially digital video—can be stored on more than just videotape. The
characteristics of the storage medium determine playback and recording capabilities.
For example, magnetic and optical disc media (CD, DVD, hard disk) are capable of
nonlinear reading and writing, while videotape is inherently linear. Videotape is still a
very efficient means of storing large amounts of digital data in a small space, but other
types of media are quickly gaining ground.
Tape Size, Cassette Shape, and Tape Coating
The width of a video tape is directly related to how much information can be stored. In
analog formats, wider tape usually yields higher quality, but other factors can help
reduce tape size with minimal loss of quality. For example, Both BetacamSP and VHS
both use 1/2”-wide tape, but BetacamSP uses a high-quality component video
recording method that keeps luma and chroma information separate, while VHS uses a
composite method that mixes these signals into one, causing interference between the
two. The physical formulation of these two kinds of tape are also different, which
accounts for some of the quality difference.
The size of the cassette itself can be varied as well. For example, the BetacamSP format
comes in both small and large sizes. The small tapes are used for camcorders, while the
large format is used in studio VTRs.
Aspects of the physical composition of magnetic tape, such as density of magnetic
particles, limits the data rate and track size that can be recorded on the tape. The
magnetic coating on a video tape is formulated to work with particular camcorder and
VTRs. If you choose the wrong tape coating, the tape can actually clog the video record
heads of your video equipment, leading to video signal dropouts during recording and
playback. Always read the documentation that comes with your video equipment
before purchasing a particular brand of video tape stock.