Using Scene Detection to Create Subclips

If you don't want to make the Subclips yourself, you can get Liquid Edition to do it by opening the clip in the Clip Viewer and using the Scene Detection tool. This is the automatic and much faster way to create individual Subclips from a long master clip.

To use Scene Detection

1.	Open a clip in the Clip Viewer. The quickest way to do this is to switch to Storyboard mode by pressing Shift+F3. This isn't necessary if you have a dual-screen setup. However, on single screens, it's the easiest way to open a clip in the Clip Viewer without adjusting any settings in Liquid Edition.
2.	Click the extended dialog arrow in the top-right corner of the Clip Viewer to display the three tabs: Video, Audio, and Scenes (Figure 14.18). Figure 14.18. The Clip Viewer with the extended dialog displayed.
3.	Click the Scenes tab (Figure 14.19) to bring up the Scene Detection options. Figure 14.19. The Scenes tab.
4.	Select either the "based on video content" or "based on metadata" radio button. See the "Video Content and Metadata Explained" sidebar for an explanation of what these do. Don't worry about the Create clips options just yet. You usually only select these once the scene detection is completed.
5.	Click Start to begin the process. The Clip Viewer runs through the scene using a low-quality picture to speed up the process. As each scene is detected, a small green marker appears on the Clip Viewer's Timeline marking the start of a scene (Figure 14.20). Figure 14.20. After the detection process, green markers set out each scene change.
6.	Create either a master clip or a Subclip from these markers by clicking the radio button next to either option and clicking the Create clips button. This creates your clips in the Rack where the original clip is stored.

Tips

• Clips created as master clips only have the amount of handle length you define in the Scene Detection options. Clips created as Subclips have a handle length that is effectively the same length as the original clip.

• When you are scanning using video content, you may adjust the sensitivity of the detection program using the Interframe Sensitivity slider. You'll need to experiment to find the perfect setting for each of your tapes.

• After scene detection, you can review the results by jumping through each scene marker using the C and V keys on your keyboard. Delete any unnecessary scene markers by clicking the Delete Marker button . The Delete Marker button isn't a default button for the Clip Viewer; therefore you must customize the Clip Viewer and add the Delete Marker button to the interface. See Chapter 1 for more details on adding buttons to the Clip Viewer. You can also clear all scene markers using the Clear all scene markers button.

Video Content and Metadata Explained

Scene detection uses two types of data to create scenesVideo Content and Metadata. Their functions are explained below.

Video Content: The Scene Detection program runs through your clip specifically looking for changes in light level, such as the change from an indoor scene to an outdoor scene. This also occurs at a pixel level, which allows the program to detect changes in screen contenta second person entering the scene, for example.

Metadata: The Scene Detection program looks for the beginning or end of a recording. Each time you click the Pause button on the camera or turn the camera off, a flag is sent to the data on the film to signal this event. This is known as Metadata.

So, which one should you use? This depends on the film you've created. If you've used the DV tape over several weeks or months, then obviously the scenes are very much dependent on the camera being turned on and off. In this case, you should use Metadata.

However, if the camera is running continuously for the whole length of the tapefilming a stage play or a concert, for examplethen you probably get better results using Video Content.