UM:Dvo Effects Dvo Flicker

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DVO Flicker

DVO Flicker analyses the image sequence to remove brightness and chrominance fluctuations. These may be caused by varying exposure time, unsynchronised light sources, telecine tranfer, aging film stock and/or film chemical related issues.

 

dv_note

Chrominance flucuations are often termed chroma breathing.

 

ch-dvo_flicker-enable

 

The effect is enabled and the colour mode of the input set via the basic setup options :

Setup

The main configuration options are described below.

Mode

ch-dvo_flicker-mode

This parameter describes the general nature of the flickering. There is one setting curernt, Location Invariant. This is a flicker that occurs globally on a frame and is not isolated to portions within a frame.

 

dv_note

Future releases will include more Mode options.

Temporal Window

ch-dvo_flicker-temporal-window

 

Values :

5, 7, 9 , 11

Default :

11

 

The Temporal Window specifies how many frames to use for the analysis.

 

dv_note

You should usually leave this at the default value.

Variation Control

ch-dvo_flicker-variation-control

 

Numeric slider, value range 0-1.

 

Range :

0 to 1

Default :

0.5

 

The Variation Control parameter sets how precise and controlled we are when we make adjustments for flicker. The higher the value we use, the more care is taken. Lower values allow for larger adjustments (less control).

 

dv_note

Lower values (allowing larger adjustments) are best for simple scenes. Larger settings may be required to take better account of more complex and dynamic scenes with more real-world intensity changes (e.g. high-speed pans etc.).

Enhanced Adjust

ch-dvo_flicker-enhanced-adjust

 

Values :

Off, Low, Medium, High

Default :

Medium

 

This will apply further processing enhancements to deal with small scale variations (both local and global).

 

dv_alert

The High setting will apply a specialised noise filter and noticeably affect processing speed.

Max Adjust Limitation

ch-dvo_flicker-max-adjust

 

Range :

0 to 10

Default :

4

 

This sets an adjustment limit to the general processing mode. The setting corresponds to a percentage (%) of the full signal.

Black Level Save

ch-dvo_flicker-black-level-save

 

Black Level Save lets us enable specific processing to preserve black levels in the sequence.

 

If enabled, the Low and High parameters are used to assign the level of processing performed at the lower (blackest) end of the input sequence. Both Low and High are 10 bit numbers and limited to values between 0 and 100 (out of the full 10 bit range, 1024).

Low

Range :

0 to 100

Default :

0

 

If the input level is less than or equal to the setting for Low, no flicker adjustment is performed and the input signal is untouched.

 

High

Range :

0 to 100

Default :

1

 

If the input level is greater than or equal to the setting for High, full flicker adjustment is performed.

 

dv_note

In between these values, there is a soft transition between none and full processing.

Chroma

ch-dvo_flicker-chroma

 

The Chroma button enables the removal of chrominance flicker (i.e."colour breathing").

 

dv_note

The Chroma toggle removes luminance flicker as well (if present). However, for best performance, leave Chroma off unless you have chrominance flickering to remove.

 

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