Apple Final Cut Pro 7 - Manual (Page 1321)

The Max. RGB Output Level slider goes between 75 and 125; 100 is the default setting.
If you want to reduce RGB levels, set the slider to a value below 100. If you want the
filter to tolerate higher RGB levels, set the slider to a value above 100.
For more detailed control, you can use the RGB Limit filter instead (see “Using the RGB
Limit Filter” ).
About Custom Luminance Limiting and Custom Saturation Limiting
The following section gives some examples to show how the Custom Luminance Limiting
and Custom Saturation Limiting controls in the Broadcast Safe filter work.
In the following example, Max. Output parameter values between 95 and 105 are
compressed down to the range between 95 and 100. The shape of the waveform is
preserved.
Start (Threshold) Clamp Above Max. Output
105
100
95
90
85
Start (Threshold) = 95 Clamp Above = 105 Max. Output = 100
In the next diagram, values above 100 are clamped, removing details above a value of
100. In this case, the Max. Output parameter has no effect because its value is identical
to that of the Clamp Above parameter.
105
100
95
90
85
Start (Threshold) = 95
Start (Threshold) Clamp Above Max. Output
Clamp Above = 100 Max. Output = 100
1321 Chapter 78 Measuring and Setting Video Levels