143
Creating a track matte effect
Creating a track matte effect
The Matrox track matte effect lets you superimpose one clip onto another using
an animated matte, sometimes called a traveling matte, to determine how the two
clips are composited (keyed). You can use any of the following types of clips as
your matte:
• A grayscale video or graphics clip.
• A graphics clip or graphics sequence with an alpha channel.
• Any clip to which you’ve applied an effect that provides an alpha channel,
such as a Matrox chroma key or 3D DVE.
When using a grayscale cl ip as your matte, areas of black in the matte create
transparent areas in your foreground clip, areas of white create opaque areas that
prevent the underlying clip from showing through, and gray areas create
semi-transparent areas in your foreground clip.
°To set up a Matrox track matte effect:
1Place your background clip (underlying image) on the appropriate lower
track in your sequence, such as on the Video 1 track.
2Place your matte clip directly above your background clip, such as on the
Video 2 track, and apply the Matrox Source Identifier effect to this clip.
¦NoteThis effect is used only to identify which clip you’re using as the matte
for your track matte effect. If you set up another effect in the same segment
that also uses the Matrox Source Identifier effect, such as for anoth er track
matte effect or an additio nal source for a Matrox cub e effect, you must assign
a unique ID number to each source clip.
3In the Effect Controls panel, click the triangle beside Matrox Source
Identifier to expa nd the property list, then select a unique ID number for
your matte clip from the Identify As list, as shown below:
¡ Important Any effect applied to your matte after applying the Matrox
Source Identifier effect will be ignored. Therefore, if you want to apply an
effect such as a Matrox chroma key or apply motion to your matte using a
Matrox 3D DVE or Adobe Premiere Pro Motion effect, you must apply this
effect before applying the Matrox Source Identifier effect.
Select a unique ID number
for your matte source