
Varying values over time
Most attribute values in VideoCanvas are timed values meaning that they can be varied over time. You can for instance have the center point of a filter move with the background, or gradually change the exposure of footage.
You can switch on or off interpolation for each timed value to control wether a transition or movement should be smooth or sudden. For that you use the attribute inspector (see below).
There are two places you can see which timed values you have: You can select the attribute in the attribute inspector and see the list of timed values for the attributes. And for point values you can also see them drawn as purple lines in the movie canvas window as depicted here:
To make something move in VideoCanvas you specify it's start position and time and then the end position and time. All values in between will be smoothly calculated.
Manipulating timed values in the attribute inspector
- See the timed values for an attribute
- Select the attribute in the attribute list of the attribute inspector. The timed values are shown in the right column of the inspector attributes and any point values are drawn in the movie canvas
- Add a timed value
- Move the time slider to the time you want
and click the + button below the timed values list.
- Change the timing or value
- Select the timed value and double click in the time column, or change the value in the value inspector below.
- Turn on or off interpolation
- Click the Smooth check box of the timed value. If it's checked the used values will smoothly change from the previous over time to the selected value. Otherwise the earlier value will be used constantly until the time of the new value which will cause the used value to suddenly change.
- Delete a timed value
- Select the timed value and click the - button below the timed values list.
- Move to the time of a value
- Selecting a timed value will set the current movie time to the time of the value.
Timed values in timeline
The times (key frames) of the selected attributes are drawn as small knobs that you can drag to the left or right adjust the timing of drag out of the Timeline to delete the key frame.
Manipulating timed values in the movie canvas
- See the timed values for an attribute
- Select the timed value by first selecting the clip, track or filter that has the attribute and then clicking on a handle
to select it. Values before the current time will be drawn in a purple curve as in the picture above.
- Automatically add a timed values
- The default behaviour: When you drag a knob or change a text on the canvas you modify the closest timed value.
Optionally: Open the application preferences (under the VideoCanvas menu) and change that to automatically create new timed values instead whenever you make an adjustment in the canvas.
See also
The attribute inspector.
Clips vs Tracks
Positioning clips.
Positioning tracks.