Apple Soundtrack Pro 2 - Manual (Page 504)

504 Appendix C Working with Professional Video and Audio Equipment
Synchronizing Equipment with a Blackburst Generator
With most professional editing systems, you capture video, audio, and timecode via
separate cables. It’s important that when you capture, the VTR and the video and audio
interfaces are synchronized via a common video timing signal. If digital audio samples
and video lines and frames are not precisely synchronized, they eventually drift apart
because they are captured at slightly different rates.
Using a common sync source is especially important when you are independently
capturing long segments of video and audio to synchronize together later. If your
audio deck and capture interface are not both receiving the same timing information,
the sync between the audio and video portions of clips might drift over time.
A blackburst generator provides a common timing signal (or clock) to lock together the
timing clocks of all devices in a system. This is sometimes referred to as external sync or
house sync because every device in an entire facility can be timed to this common
reference.
Professional VTRs, camcorders, audio devices, and interfaces often have the ability to
accept sync signals from an external device. These connectors are labeled “genlock”
(short for generator lock), “external sync”, “reference input”, or “reference video”. On some
equipment, the normal composite video input of a device can be used to lock to
external sync.
Important: To synchronize your video or audio devices and interfaces, they must all
accept an external clock source (such as a blackburst generator).
A Recommended Audio System Using a Third-Party Audio Interface
To set up a system using a third-party audio interface, you need the
following equipment:
 Your computer and display
 A device-controllable audio deck, such as a DAT or multitrack deck
 Appropriate analog cables for your system
 An audio interface
Note: Some third-party PCI interface cards have a breakout box connected to the
card with a special cable.
 A USB-to-serial adapter or internal modem serial port adapter
 A blackburst generator, with the appropriate cables to connect it to both your
third-party audio interface and your audio deck. (For more information, see
“
Synchronizing Equipment with a Blackburst Generator ,” next.)
 An RS-422 video deck control cable