Working with the BCC Displacement Map Filter

The Displacement Map Þlter uses the luminance or color information from an alternate video or still image track (the Map Layer) to displace the pixels in the source image horizontally and vertically. This Þlter creates a distorted version of the source whose distorted regions correspond to the luma or color channel of the Map Layer�s media.

Source image Map Layer Filtered image

The Displacement Map Þlter includes extensive parameters for you to customize. You may need to scroll to see them all. The illustration at right does not show all the parameters.

The BCC Displacement Map can also be used as a transition. To apply a Displacement Map as a transition, use the BCC TR Displacement Map in the BCC Transitions category or apply the Þlter to two layers.

General Controls Parameter Group

At times, you may want to view your clip without the effect that you�ve applied. The

Bypass Effect checkbox

lets you view the source footage without the effect. When the Bypass Effect checkbox is

selected, it turns pink. When you applied a BCC effect to an Avid title or matte, enabling the

Bypass Effect checkbox

does not display the original title unÞltered, but rather displays the nested Graphic Fill of the matte key.

Bypass Effect is a parameter change; selecting the Bypass Effect checkbox will unrender a rendered effect. To bypass a rendered effect without unrendering, step into the effect in the Avid timeline to see the unaffected video.

Selecting the

Safe Colors checkbox

enables an NTSC/PAL color-safe Þlter that allows only colors that are safe for broadcast. BCC allows RGB values across the full 0-255 range. When this checkbox is selected, the RGB values are limited to the NTSC/PAL safe range of 16-235.

The

Draft Mode checkbox

allows you to preview your effect in a Draft Mode to speed previews. This is especially useful for effects with multiple track inputs. Deselect this option before rendering your effect.

The

Apply to Title-Matte checkbox

allows you to apply BCC Þlters to titles created in Avid�s Title tool. To apply an effect to a title, drag the effect onto the title (you do not have to Option-drag) and select the

Apply to Title-Matte checkbox

.

The

Invert Matte checkbox

allows you to invert any matte created by your effect. This is useful when you work with imported images.

The

Layer Opacity

slider sets the opacity of the Þlter layer, which allows you to fade effects. When

Apply to Title-Matte checkbox

is selected, Layer Opacity affects the graphic Þll layer, which allows you to fade titles.

The

Field Render menu

sets the rendering optimization for BCC. For most Þlters, you can use the default of

Speed Optimized

. For effects that include edging or DVE moves, you may want to use

Quality Optimized

. Quality Optimized takes more time to render, but will generally correct any problems with jitter or rough edges on effects.

Geometrics Parameter Group

The controls in the Geometrics parameter group allow you to add basic DVE moves to any Þlter.

The Geometrics parameter group includes the following controls.

Selecting the

Enable Geometrics checkbox

allows you to use the parameters to reposition a track. When this checkbox is deselected, the other parameters have no affect.

Position

X

and

Position Y

adjust the horizontal and vertical location of the track.

Scale X

and

Scale Y

change the size of the image along the X and Y axis, respectively. These parameters scale as percentages of the image�s original width and height. Thus, a Scale X value of 200 produces an image twice as wide as the original. Select the

Lock Scale checkbox

to keep the Scale X and Y values in proportion.

Tumble

,

Spin

, and

Rotate

change the image�s perspective along the X, Y, and Z axes respectively. Tumble, Spin, and Rotate can animate over values greater than 360° in order to make the shape complete more than one full revolution.

Tumble Spin Rotate

The Crop controls crop the edges of the image.

Left Crop, Top Crop

,

Right

Crop,

and

Bottom Crop

determine the width, in pixels, of the cropped area on each edge of the image.

For the Crop controls refer to the sides of the original image before it is transformed in 3D space. For example, if you tumble an image 180° so that it appears upside-down, cropping the Top affects the top of the original image, which is actually the bottom of the tumbled image.

The

Blend

control soften the edges of the image by reducing their opacity. The

Blend

parameter

determines the width, in pixels, of the transparent band on each edge of the image. These values are unaffected by the Crop values, allowing you to soften the edges of an uncropped image.

Drop Shadow Parameter Group

The controls in the Drop Shadow parameter group allow you to add an animatable drop shadow to an effect.

The Drop Shadow parameter group includes the following controls.

The

Enable Drop Shadow checkbox

turns the shadow on and off. If this checkbox is not selected, the other parameters have no affect.

Source Opacity

sets the opacity of the source. You can use this parameter to fade in a title or other source, without fading in the shadow.

Distance

sets the distance (in pixels) between the shadow and the image.

Intensity

sets the opacity of the drop shadow, and is scaled as a percentage. At a value of 100, the shadow is completely opaque. Lower Intensity values allow the background image to be seen through the shadow. At a value of 0, the shadow is completely invisible.

Softness

controls the softness of the edges of the shadows. A setting of 0 produces a sharply deÞned shadow with hard edges. Increasing Softness produces shadows with softer edges.

Angle

sets the direction of the drop shadow. A setting of 0° places the shadow to the right of the image; a setting of 90° places it directly below the image.

Shadow Color

sets the color of the shadow.

If the source image is opaque, selecting the

Opaque Source

checkbox

can speed rendering and previews. If your source is partially transparent, deselect this option for best results.

The

Map Layer menu

determines which clip layer in the timeline is used to create the distortions in the source image.

If the Map Layer is partly transparent, the displacement amount is scaled by its alpha values. Pixels whose map alpha is 0 are not displaced.

Source image Map Layer Filtered image

You can use the Noise Map Þlter to create auto-animated noise patterns that create a continuously ßowing displacement effect. Luma gradients also make good Map Layers. You can also try using a title or logo to create a displacement as shown in the example at right.

Map Parameter Group

The Map parameters control the appearance of the map used to distort the source image.

Pre Blur

applies a blur to the Map Layer. Increasing Pre Blur can help eliminate sharp edges in the map to create a smoother effect.

Pre Blur=0 Pre Blur=50

Displacement Þlters often look rough if the Map Layer is high-contrast or has sharp edges.

Blur Threshold

softens the Map Layer before computing the displacements. After the Map Layer is blurred, the blurred track is compared to the original Map Layer, and the color change for each channel is reduced by a relative amount. Increasing Blur Threshold blurs parts of the image with rapid changes in color without blurring subtle details. This is particularly appropriate for a displacement map, which can severely distort areas of the image where the Map Layer changes rapidly.

Map Black Level

sets the channel values of the map that are output as pure black. All pixels whose value is lower than the Map Black Level value become pure black. For example, if Map Black Level is set to 50, all pixels with a value of 50 or less output to a value of 0. The remaining values (50-255) are remapped to produce a smooth gradient from black to white.

Map Black Level=0 Map Black Level=75

Map White Level

sets the channel values of the input image that are treated as pure white by the Þlter. All pixels whose value is higher than the Map White Level value become to pure white. For example, if Map White Level is set to 200, all pixels with a value of 200 or more are output to a value of 255. The remaining values (0-200) are remapped to produce a smooth gradient from black to white.

Map White Level=255 Map White Level=175

Displacement Map 1 Parameter Group

The

View Map checkbox

allows you to view the Map Layer as you make adjustments to it. Deselect this option before rendering.

The

Horizontal Channel menu

is the channel in the Map Layer used to compute horizontal displacement. The choices are

Red

,

Green

,

Blue

,

Luma,

White

,

Gray

, and

Black

. White treats all of the pixels as if they were white (i. e. fully displaces each pixel to the Max. Horizontal value). Gray treats all pixels as if they were 50% gray (resulting in no displacement). Black treats all pixels as if they were black, thereby displacing all pixels to the negative of the Max. Horizontal Displacement value.

Max. Horizontal Displacement

sets the amount of horizontal displacement for pixels in the Map Layer. Positive values move points that correspond to white pixels in the Map Layer to the right; points that correspond to black pixels displace to the left. For negative values, pixels are displaced in the opposite direction (white pixels move to the left and black pixels to the right). The displacement of gray pixels is interpolated between these values. 50% gray pixels undergo no displacement, because they are �pulled� equally in both directions.

Max. Horizontal=25 Max. Horizontal=75 Max. Horizontal=175

The

Vertical Channel menu

sets the channel in the Map Layer used to compute vertical displacement. The choices are

Red

,

Green

,

Blue

,

Luma,

White

,

Gray

, and

Black

. White treats all pixels as if they were white (fully displaces each pixel to the Max. Vertical Displacement value). Gray treats all pixels as if they were 50% gray (resulting in no displacement). Black treats all pixels as if they were black, thereby displacing all pixels to the negative of the Max. Vertical Displacement value.

Max. Vertical Displacement

sets the vertical displacement for pixels. White pixels are displaced upward by this amount, and black pixels are displaced downward by this amount. The displacement of gray pixels is interpolated between these values. 50% gray pixels undergo no displacement, because they are �pulled� equally in both directions.

The

Map Behavior

menu

determines how the map is applied when the source image is a different size than the image in the Map Layer. If your map is the same size as the image to which you are applying the Þlter, the Map Behavior settings all produce the same result.

•

Center Map

centers the map on the source and does not displace the source image outside the boundaries of the centered Map Layer.

•

Stretch Map to Fit

resizes the Map Layer to the size of the source.

•

Tile Map

creates tiles from the Map Layer and uses them to displace the source. Tile Map only has an effect when the map is smaller than the source image.

PixelChooser Parameter Group

The PixelChooser is included in many Boris Þlters and provides several methods to selectively Þlter an image. You can use the PixelChooser to create a matte between Þltered and unÞltered pixels, either by specifying a geometric region or by using the image�s luma or color information.

See the individual PixelChooser Þlter for more detailed information on the PixelChooser controls.

Working with the Pinning Controls

A displacement Þlter might distort the image in such a way that it creates holes at the edges of your image, or, at more extreme settings, tears holes in the center of your image. The pinning controls can counteract this effect by undistorting the image at speciÞed edges, or in regions around up to two chosen points (�pin points�) within the image.

No Pin Pin All Edges

The most important control on this section is

Edge Pin

, which determines which edges are pinned. You can pin any or all of the edges, the center of the image, or only the horizontal or vertical edges.

The default setting pins all the edges, which prevents edge distortion at most parameter settings. However, pinning cannot always prevent tearing at extreme settings. Increasing

Edge Pin Width

can help by undistorting within a greater distance from the edges. For effects that involve less distortion, a smaller Edge Pin Width prevents the edges from tearing and looks more realistic.

Pin Point 1 and Pin Point 2 Parameter Groups

Pin Point 1

and

Pin Point 2

set the coordinates of a pin point. A pin point is a point at which the image is undistorted. The remaining Point 1 controls affect the distortion in a circular region (the pin region) centered around this point. The Pin Point 2 parameters apply a second pin point. These parameters function identically to the Pin Point 1 controls.

Point 1 Strength

sets the amount of pinning applied to the image at the pin point. The default value of 100 completely undistorts the pin point. Decreasing values reduce the effect of the pin point, and at a value of 0, the point undergoes the full distorting effect of the Þlter. In other words, when Point 1 Strength is 0, the Pin Point 1 has no affect.

Point 1 Range

sets the radius (in pixels) of the Pin Point 1 region.

Point 1 Center %

sets the percentage of the pin region for which the pin is fully applied. For example, if you set Point 1 Range to 100, and Point 1 Center % to 50, then pixels within 50 pixels (50% of the Point 1 Range setting) are completely undistorted, and pixels within 50 to 100 pixels are partially undistorted.