Performing a Confidence Check
Chapter 7, Editing

Use scene detection when you are working on a single shot made up of multiple scenes. Scene detection locates the frames when scenes change and splices the shot at those points. When you apply scene detection to a shot in the Storyboard, it is broken up into numerous smaller pieces that you can then colour grade independently.

For example, you may have a finished edited HD master tape that needs to be colour graded before it is ready for broadcasting. You can capture the entire tape as one shot, and then use scene detection to cut it into separate shots. You can then colour grade each shot one-by-one.

Note: Lustre uses the scene's Src In number to assign unique ID numbers during scene detection. This ensures that any scene captured more than once has the same number assigned to it, which is useful when scenes are transferred from Lustre to other effects applications, and back again. By using the Src In number as the basis for assigning numbers, the grading metadata applied to a scene that has been captured and put through scene detection more than once, is maintained.

1. Capture from an edited video tape. See Capturing Material.

2. Create a new empty cut. See Working With Cuts.

3. Drag the digitized shot from the Shot bin to the Storyboard.

4. Click Editing, and then click Edit to display the Edit menu.

5. Enable Scene Detect.

   

   Hint: If the Editing While Grading button is enabled in the User settings, you can start a scene detection from any menu by pressing Shift+S. For more information about the Editing While Grading button, see System & Menu Settings.

   A threshold indicator bar appears to the right of the Shot bin. When a scene change is detected, the indicator jumps and turns red, and a splice is introduced into the Storyboard, Timeline, and timebar at that frame. When the process is completed, a series of shots is created in the Storyboard.

6. You can change the threshold by dragging the thin black horizontal line in the threshold indicator up or down. When you lower the threshold value, a small amount of change is enough to trigger a splice. If the value is too low, splices appear in the middle of a scene. If the value is too high, some changes may not be detected. Generally, the default threshold value gives a good result.

   

   Images courtesy of Hungarian Academy of Film & Theatre, 3rd year

   
   

7. Press Spacebar to pause the scene detection process.

   Note: To continue a paused scene detection, press Spacebar again. To stop scene detection, hold down your left mouse button.

8. If, for any reason, a scene change is not detected, you can add a cut manually by clicking Cut. See Inserting Cuts.