Apple Soundtrack Pro 2 - Manual (Page 498)

498 Appendix C Working with Professional Video and Audio Equipment
Amplifiers and Signal Levels for Unpowered Speakers
Unpowered speakers require signals with higher voltage than consumer and
professional equipment can provide directly. These levels are known as speaker level
audio signals, while audio devices such as tape recorders and audio mixers usually
provide line level signals. An audio amplifier boosts line level signals to speaker levels
to properly drive speakers. Wide-gauge speaker cables that can handle the higher
electrical strength of speaker levels are used to connect the amplifier to speakers.
Connecting Professional Video Devices
Regardless of what format or video interface you use, the same basic steps apply when
you connect a VTR or camcorder to your computer.
Connecting Professional SD Video Devices
If you’re using a format other than DV, such as Betacam SP or Digital Betacam, you
need to install a third-party video interface that supports the proper signal for the
format you’re using. Some video interfaces can digitize analog video input and output
(for analog formats like Betacam SP), while others capture video only if it is already
digital. In either case, the video interface encodes the video information using a codec,
which may or may not apply compression to the video data to make it smaller while
stored on disk. Compression settings used by video interfaces are typically controlled
by software and use a variation of the M-JPEG codec (although the name of the codec
itself may not reflect this).
Unlike DV video devices (which use a single FireWire cable), third-party interfaces send
and receive video, audio, and device control data on separate cables. For remote device
control connections on professional equipment, 9-pin (DB9) connectors are used.