Adobe Ultra CS3 User Guide

Moving and scaling an input within the layer plane: Input Offset controls

If you're not familiar with how moving a layer with the Input Offset controls on the Input tab differs from repositioning a layer by using the Input Position In Scene controls on the Scene tab, see Positioning layers and performing virtual camera moves.

A) Black box represents the borders of the layer plane. Content outside this box is cropped.
B) Y axis - Vertical position: Drag up and down.  C) Angle: Ctrl-drag vertically.  D) Scale: Shift-drag vertically.  E) X axis - Horizontal position: Drag sideways.

Use the Input Offset controls, which are at the center of the Input tab, to move and scale the active layer within its layer plane. For more information, see Differences between sets of Position controls. In general, you should use these controls only when the Input Position In Scene controls on the Scene tab are locked for the layer, which they are for the input clip in a VirtualTrak set and for all insets (Source B, C, and so on) in all virtual sets.

The black box in the Input Offset grid control represents the layer plane. It does not change to reflect the size or orientation that is set by using the controls on the Scene tab. If you change the Input Offset so that any part of the image lies beyond the black box (see the pink areas in the previous graphic), that part is cropped from the image. Conversely, any places where the edge of the grid is within the layer plane (see the checkerboard areas in the previous graphic) appear either transparent or black, depending on the set. The following graphic shows what would be displayed with the Input Offset settings from the previous example.

Given how these controls function within the layer plane, these controls are useful in the following situations:

    Repositioning an input clip in a VirtualTrak scene. VirtualTrak sets lock the Input Position In Scene controls that you usually use for this purpose. These controls are particularly valuable in this regard if the input clip is a few pixels off so that the subject appears from the middle of space rather than emerging from behind a door, pillar, or other foreground element.

    Zooming in on a part of the image by increasing the scale of the source and, if necessary, repositioning it for the desired framing.

NOTE

 

The Input Offset controls require hardware capabilities that not all video cards support. For those video cards, you may see artifacts around an image when it does not fill the layer plane. In some cases, cropping the edges slightly with the Input Cropping tool can delete the visible repeat. For more information, see Cropping the edge of a frame.

NOTE

 

Vertical, horizontal, and angular movement is relative to the native coordinates of the source. If you rotate the source or flip it in either dimension by using the position and orientation controls on the Scene tab, then the image's motion seems contrary to the mouse's movement.

 

If you're working with a keyed input clip and want to see the size, position, and orientation of the input clip within the frame, try either disabling the keyer or switching to a solid image. The easiest way to do this is to right-click the Input Clip thumbnail, and then choose Assign White, Assign Black, or Assign Checkerboard. When you're ready to see the keyed video against the background again, right-click the Input Clip thumbnail, and then choose Reassign Last Source.