UM:Dvo Effects Dvo Warp

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DVO Warp
From Release : 2013.2.076


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DVO Warp is an intelligent automatic tool for removing warping artifacts often associated with line scanners.

The current version of the tool deals with vertical warping. The tool should be considered very precise, with results hard to match for any manual/semi-manual process.

A high priority is given to safety, so the tool can be run largely unsupervised without creating issues.

Parameters
Enable / Mark

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Enable Enable enables/disables the tool.
Mark Mark enables diagnostic marking of the processed (de-warped) frames by drawing a white circle in the upper right corner of the image. DEFAULT is off.
Profile

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This control is used to set internal configuration parameters to match specific behaviors which have been identified (such as a specific scanner type).

The different profiles available are :

General The general mode for sources which are unknown or don't have a profile. This is the DEFAULT.
GE-III (a) Golden Eye III model A – the most common model.
GE-III (b) Golden Eye III model B – uncommon model with a different mechanical construction which affects warping behavior.

The Profile setting does not visually change any of the other user parameters, but may in some cases affect how they are interpreted. In particular, the Sensitivity parameter may be interpreted for conditions matching a specific profile. The General profile mode has no specific tuning and expect this mode to have the greatest effective range for a parameter such as Sensitivity.

Sensitivity

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Range 0.0 - 1.0
Default 0.5

This parameter sets the general sensitivity for the detection and selection of warped frames to process.

A low sensitivity corresponds to warps with high “amplitude” (more visible) and high sensitivity then corresponds to warps with low amplitude (less visible).

If you set sensitivity too high the actual processing may become much harder even to the point that the algorithm cancels it for safety reasons.

Sensitivity should mainly be tuned for a common source, splice and scanner. It should normally not have to be tuned for specific clips.

Safety
Range 0.0 - 1.0
Default 0.5

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The Safety parameter lets the user choose a desired "safe" processing level, therefore placing limits on how much de-warping to do. Processing will be cancelled if it is considered unsafe (hitting this user set limit).

The larger the value, the safer we will be, and the less risk of over-processing.

This parameter is of a statistical nature and targeted for setting a comfortable level for unsupervised processing (of a lot of material). The effect of the parameter range may not always be noticeable for an individual clip.

Whatever the setting for Safety, processing may be cancelled for a specific shot because any amount of de-warping may end up being considered unsafe.

Offset

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When a frame is warped it normally exhibits some kind of offset or jump. By default the de-warp algorithm will try to stabilize such offsets.

Offsets cannot always be stabilized (hence "Try Stabilize"). The internal stabilization is fairly basic and as an alternative the more advanced DVO Steady II can be used and may be a better choice.

This functionality only affects the actual frames being de-warped.

Options are:

Keep Keeps the average offset of each frame.
Try Stabilize As described stabilizes frame offset/jumps when possible. This is the DEFAULT.
Scene Mode

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Frames affected by warping issues are often found on either side of a physical splice. By default the tool is set to only analyze frames on either side of a scene cut, but it can also be set to analyze all frames.

Start Only
Setting Enabled by default
Range 0 - 50
Default 30

Enables analysis/processing at the start of the scene. Also set the number of frames after the scene cut which should be analyzed.

End Only
Setting Enabled by default
Range 0 - 50
Default 30

Enables analysis/processing at the end of the scene. Also set the number of frames before the scene cut which should be analyzed.

Full analysis/processing of all frames is enabled when both Start Only and End Only have been disabled.

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Region Of Interest

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The Region of Interest setup here is specific to DVO Warp.

Left / Right

The left and right sides are used to isolate the area used for warp analysis.

This is useful for selecting an area which may be easier to analyze in some circumstances. The algorithm should be quite robust under many conditions, but if a part of the frame is largely filled with complex motions this is a useful way to disregard them.

DVO Warp will analyze the set region only but still process the full frame.

Top / Bottom

The use of top and bottom will have an effect on the actual processing.

Areas outside any top or bottom set will not be de-warped by the tool. However, these areas will still be repositioned according to the position offset of the inside of the ROI (i.e. top and bottom line).

These can further be controlled in the graphical ROI overlay by selecting and repositioning the lines for left, top, right and bottom.

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