Setting QuickTime transition effects for two source filters

When you set transition effects for two source filters (see Adding and applying two source filter tracks), you can set the following alpha channel based effects in the Select Effect dialog box:

Alpha Compositor

Use this effect to combine two images using the alpha channels of the images to control the blending. It provides for the standard alpha blending options, and can handle pre-multiplying by any color, although white and black are most common and often run faster. The alpha compositor effect has one parameter, Blend mode, that can contain one of the following values:

• Straight alpha performs a standard alpha blend. The alpha channel value of the first track defines the amount of that track that is included in the composite image. One minus the alpha channel value of the first track defines the amount of the second track that is included in the composite image.
• Pre-multiply alpha calculates the destination pixel based on the color you specify in the Pre-multiply color field.
• Reverse alpha performs a reverse alpha blend.

Chroma Key

The chroma key effect combines two tracks by replacing all the first track's pixels (specified in the Key Color field) with the corresponding pixels of the second track. This allows the second track to "show through" the first in those places where the first track has the specified color. The Key Color is the chroma key color to replace in the first track with pixels from the second track.

The following effects are transitions between two tracks:

Cross Fade

A "cross fade" or "dissolve" provides a smooth alpha blending between two video sources, which results in a smooth fade out from the first track into the second. This effect has one parameter--Percentage. The two slider controls let you manipulate the degree of visibility of either source during the blend.

Explode

In an explode effect, track B grows from a single point expanding out until it entirely covers track A. This effect has three parameters:

• Percentage: The two slider controls let you manipulate the degree of visibility of either source during the blend.
• Explode Center X: The x-coordinate (horizontal) of the explosion center.
• Explode Center Y: The y-coordinate (vertical) of the explosion center.

Gradient Wipe

The Gradient Wipe effect transitions between two tracks, with the change pattern controlled by an input image. At the start of the effect, the area covered by the input image shows the first track, while the area outside the input image shows the second. Over the duration of the effect, the input image shrinks until only the second track is visible. The gradient wipe effect has three parameters:

• Percentage: The two slider controls let you manipulate the degree of visibility of either source during the blend.
• Matte: The input image that controls the transition between the two tracks.
• Edge Blur: The slider from 0 to 255 controls the amount of edge blur, or distortion, that the leading edge of the gradient wipe displays.

Implode

In an implode effect, track A shrinks down to a single point, revealing track B. The center point of the implosion is defined in the effect parameters. The implode effect has three parameters:

• Percentage: The two slider controls let you manipulate the degree of visibility of either source during the blend.
• Implode center X: The x-coordinate (horizontal) of the implosion center.
• Implode center Y: The y-coordinate (vertical) of the implosion center.

Push

A push is an effect where one source image replaces another, with both tracks moving at the same time. For example, track A would typically occupy the entire screen, and then track B would slide in from the left, while track A slides out to the right at the same time. The push effect has two parameters:

• Percentage: The two slider controls let you manipulate the degree of visibility of either source during the blend.
• Push from: Controls the direction from which track B replaces track A. This parameter can contain Top, Right, Bottom, and Left.

Slide

In a slide effect, track B slides into the screen to cover track A. At the end of the effect, track B completely covers track A. The slide effect has two parameters:

• Percentage: The two slider controls let you manipulate the degree of visibility of either source during the blend.
• Angle: The angle from which track B enters the frame. This value is expressed in degrees, with 0 degrees defined as the top of the screen.

Iris, Matrix Wipe, Radial, Wipe

Each of these effects is an implementation of a series of masking or "reveal" type effects that take place between two tracks. Each has seven parameters:

• Percentage: The two slider controls let you manipulate the degree of visibility of either source during the blend.
• Wipe Type: By setting this parameter, you control which of the 13 available wipes, listed in the Wipe Type menu, is used. You can preview the wipe types in the preview pane of the Select Effects dialog box.
• Horizontal repeat: The number of horizontal repeats of the effect that occur in a single track.
• Vertical repeat: The number of vertical repeats of the effect that are executed in a single track.
• Border width: The width, in pixels, of a border that is drawn around the second track.
• Border color: The RGB color of the border around the second track.
• Soft edges: If the option is selected for this parameter, the border drawn around the second track is blurred.

Zoom

This filter produces a zooming effect of one image (B) over (or from) another image (A). The Zoom filter has four parameters:

• Percentage: The percent, or amount, of the area that the zooming image (B) zooms. The left zoom percentage setting controls the zooming image (B) from its starting point (center to outer), and the right side controls the zooming image from the end point (outer back to center). You can adjust the two percentage settings and watch the effects of zooming in and out, zooming image B over a large portion of image A, zooming image B over a very small portion of image A, or a combination of the two so that the zooming object "zooms in place."
• Zoom Type: Lets you control which images zoom. Zooming B over A zooms image B out from or into a static image A. Zooming B over Zooming A zooms image B out from or into a zooming image A. Zooming A simply zooms image A.
• Zoom Center: The X and Y axis settings adjust the horizontal and vertical start or end point of the zooming image, depending on the area percentage settings.
• Distance: The amount of travel space or velocity that the image zooms.