Final Cut Pro 6 - Broadcast Safe Filter Controls

Chapter 26

Measuring and Setting Video Levels

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III

Luma/Chroma Mode Pop-Up Menu
Choose one of the presets in this pop-up menu to decide the maximum allowable
chroma saturation. The normal setting of 120 should work in most situations; however,
more conservative settings are available.

Note: The number in the preset refers to the value of the combined luma and chroma
signals, mostly weighted toward the luma signal.

If you choose Custom from the Luma/Chroma Mode pop-up menu, you can use the
sliders in the Custom Luminance Limiting and Custom Saturation Limiting areas to
manually fine-tune clamping of luma and chroma levels. If any mode other than
Custom is chosen, the Custom Luminance Limiting and Custom Saturation Limiting
sliders have no effect.

Custom Luminance Limiting Controls
 Enable: Select or deselect the checkbox to enable or disable the Custom Luminance

Limiting controls.

Note: The sliders below have an effect only when this checkbox is selected.

 Clamp Above: All luma values above this parameter value are clamped to the

parameter value. The lower you set this value, the more clipping occurs at the top of
the waveform.

 Max. Output: Compresses the range of values between the Start (Threshold) and

Clamp Above values so the maximum output value is the value set here. Setting this
value higher than the Clamp Above value has no effect. Values below the Start
(Threshold) value clip the signal.

 Start (Threshold): Defines the lowest value affected by the Custom Luminance

Limiting controls.

Options in the Luma/
Chroma Mode pop-up
menu

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Part III

Color Correction and Video Quality Control

Custom Saturation Limiting Controls
 Enable: Select or deselect the checkbox to enable or disable the Custom Saturation

Limiting controls.

Note: You can still adjust the sliders below, but they have an effect only when this
checkbox is selected.

 Clamp Above: All chroma values above this parameter value are clamped to the

parameter value. The lower you set this value, the more clipping occurs.

 Max. Output: Compresses the range of values between the Start (Threshold) and

Clamp Above values so the maximum output value is the value set here. Setting this
value higher than the Clamp Above value has no effect. Values below the Start
(Threshold) value clip the signal.

 Start (Threshold): Defines the lowest value affected by the Custom Saturation

Limiting controls.

 Reduce Chroma/Luma: When the combination of the luma and chroma signals is

too high and the Broadcast Safe filter can reduce either luma or chroma to make
the combined signal legal, this parameter determines how much luma and chroma
are reduced. When the slider is set to 100 (centered), the filter reduces luma and
chroma equally.

Note: The Custom Luminance Limiting and Custom Saturation Limiting controls are
effective only when you choose Custom from the Luma/Chroma Mode pop-up menu.

RGB Limiting Controls
 Enable: Select or deselect the checkbox to enable or disable the Max. RGB Output

Level parameter. When this parameter is enabled, any equivalent RGB values that
exceed the Max. RGB Output Level parameter value are clamped to that value.
Negative RGB values are automatically clamped to zero.

Note: Unlike the Custom Luminance Limiting and Custom Saturation Limiting
controls, this option can always be enabled, regardless of the option currently
selected in the Luma/Chroma Mode pop-up menu.

 Max. RGB Output Level: This parameter value is the maximum RGB-equivalent value

that the filter outputs.

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

” on page 531).