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# Adding Effects to Media

The Media list allows you to easily add and edit effects to your clips, such as blurs and crops.

## Blurring a Clip

To blur the front, matte clip, or back clip for the selected media, use the Xblur and Yblur fields. The Xblur field controls the amount of blurring on the horizontal (X) axis, and the Yblur field controls the amount of blurring on the vertical (Y) axis.

NoteIf you apply the media to more than one surface, all the surfaces are blurred.

(a) Xblur(b) Yblur(c) Gaussian Blur

You can use a Gaussian (Gaussian enabled) or a Box blur (Gaussian disabled):

- Gaussian blur has rounded, smoother edges. It is a better blur for animation because it can be blurred on a subpixel level (0.00).
- Box blur has rectangular, rougher edges.

To blur the front clip of media:

1. In Action, click Media.
2. Select the front media.
3. To use a Gaussian blur, double-click the Gaussian field (otherwise a Box blur is applied).
4. Set the blur using the Xblur and Yblur values, and then negate the values for the Blur fields on the matte media. For example, to blur only the front clip 10 pixels on both axes, set the front Xblur and Yblur fields to 10 and the matte Xblur and Yblur fields to -10.
   Tip Alt-drag over the XBlur or YBlur field to change both values proportionally.

To blur the matte clip of media:

1. In Action, click Media.
2. Select the matte media.
3. To use a Gaussian blur, double-click the Gaussian field (otherwise a Box blur is applied).
4. Set the matte Xblur and Yblur fields. Blurring only the matte clip produces a softer edge on the surface of the front clip.
   Tip Alt-drag over the Xblur or Yblur field to change both values proportionally.

## Cropping a Clip

When you crop media, the front and matte clips are cropped together. You cannot crop the back clip. If you applied the media to more than one surface, all the surfaces are cropped.

You can animate a crop by changing the size and shape of the Crop box at different keyframes. You can also animate the softness of the Crop box.

NoteAnimating a crop in the Channel Editor does not enable the Crop field in the Media list.

To crop a clip with the Media list:

1. In Action, click Media.
2. Set values for cropping and softness in the Top, Bottom, Left, and Right fields. Once you set a value in one of the Crop or Softness fields, white checkmarks indicate that Crop and Softness are enabled.

   (a) Softness area of Crop field(b) Crop area of Crop field

   Tip Alt-drag over one of the fields to change all four values proportionally.

To crop gesturally in the image window:

1. Double-click the Crop field to enable Crop and Softness.
2. In the View box, select Media Front or Media Matte.

   The clip appears in the image window with a red outline, which indicates the Crop box, and a green outline, which indicates the Softness box.

   (a) Crop box(b) Softness box

   TipYou can use two viewports to view the crop interactively on both the front and the matte clips.
3. Set the corners of the Crop box and Softness box by dragging either the corners or edges of the red and green outlines.

   The crop and softness values in the Media list are updated as you drag.

4. Click Result.

   The cropped media appears in the image window, and the front and matte clip share the same crop.

5. To mute the Crop and Softness values, double-click the Crop field. To mute only the Softness, double-click the Softness area of the Crop field. When muted, a black checkmark appears in the Crop field.

## Eliminating Unwanted Black in Areas of Media Transparency

When compositing with images generated by rendering 3D objects over a black background, unwanted black often appears on translucent or anti-aliased areas of the media. Use the Divide tool to divide the front media by its associated matte media, which eliminates the black edges in the composite.

To remove unwanted black in media transparency:

1. In Action, click Media.
2. In the Media list, select the media containing the unwanted black.
3. Double-click the Divide field of the media containing the unwanted black.

   The selected media's front is divided by its matte, resulting in correct colour in areas of transparency.

## Slipping Media

You can animate the Slip value of a media's front, matte or background clip. Do this to begin a clip at a specified frame number, or to produce a freeze frame effect where the first frame is held for a specified number of frames. In addition, Slip values are animatable for all types of clips.

If you want to animate the Slip values, or control the Front Slip and Matte Slip separately, use the Channel Editor. The channels are found in their respective media and are named Slip and slip_matte. The Background Slip channel is found in Scene Media Background Slip.

To slip media:

1. In Action, click Media.
2. Change the value of Slip for either the Front or Matte fields, or both, of the media you want to slip.
   Tip Alt-drag over the Front or Matte slip field to change both while maintaining the same offset.

   A positive value starts the clip at the specified frame. A negative value creates a freeze frame effect where the first frame of the clip is held by the specified number of frames.

To slip a background clip:

1. Change the value of the B (background) Slip field.