Apple Final Cut Pro 5 - Manual (Page 326)

Chapter 23 Using Color Bars for Video Calibration 325
IV
Measuring Analog Video During Output
If you output to analog tape using the built-in FireWire interface of your computer with
a consumer DV device, keep in mind that not all DV devices use the same analog black
level. While the digital video signal output from FireWire always has a digital black
value of 0 percent, some DV devices output analog black around 0 IRE, and others
around 7.5 IRE, depending on the model. Professional video facilities are fairly stringent
about keeping black levels at precisely 0 IRE for PAL and for NTSC in Japan, and at 7.5
IRE for NTSC in the United States. If your DV device outputs at the wrong analog black
level, you may need to use a hardware proc amp (processing amplifier) to adjust your
analog video signal accordingly.
Using the Waveform Monitor and Vectorscope
Before logging new clips, it’s a good idea to check the bars of each new tape you log
with the Waveform Monitor and Vectorscope in Final Cut Pro. You can also make
adjustments to individual clips on tape, if necessary. Final Cut Pro saves individual
image control settings with each clip you log. You can then have Final Cut Pro capture
your offline clips using these individually saved image control settings.
What Is Setup?
Setup refers to the black level of an NTSC analog video signal. If you use a hardware
proc amp to adjust an incoming or outgoing analog video signal, the setup control
will allow you to adjust the analog video signal’s voltage level for black.
If you are outputting back to analog tape using a third-party analog video interface,
you should check the documentation that came with the video interface to
determine how to configure the video interface for the U.S. standard for setup (7.5
IRE) or the Japanese standard (0 IRE). Most vendors of analog video interfaces include
a software control panel that allows you to select which black level to use. Most
vendors label this as “7.5 Setup” vs. “0 Setup,” or in some cases “NTSC” vs. “NTSC-J.”
If you’re outputting back to digital tape using a digital signal (for example, SDI or HD-
SDI) and a third-party digital video interface, you don’t need to worry about setup
levels, because the digital values for black and white specified by the International
Telecommunications Union (ITU) are standardized worldwide, and are the same as
the digital values Final Cut Pro uses.