Adobe 12040118 Tutorial - Page 214

more information, see Tracking 3D camera movement (CS6). Note: In After Effects CS5.5, and later, you can stabilize shaky footage a lot easier using the Warp Stabilizer. For more information, see Stabilize motion with the Warp Stabilizer effect (CS5.5 and later). Uses for motion tracking and stabilization Motion tracking has many uses. Here are some examples: Combining elements filmed separately, such as adding video to the side of a moving city bus or a star to the end of a sweeping wand. Animating a still image to match the motion of action footage, such as making a cartoon bumblebee sit on a swaying flower. Animating effects to follow a moving element, such as making a moving ball glow. Linking the position of a tracked object to other properties, such as making stereo audio pan from left to right as a car races across the screen. Stabilizing footage to hold a moving object stationary in the frame to examine how a moving object changes over time, which can be useful in scientific imaging work. Stabilizing footage to remove the jostling (camera shake) of a handheld camera. Depending on the encoder you use, it is possible to decrease the size of your final output file by stabilizing motion footage. Random motion, such as from the jostling of a handheld camera, can make it difficult for many compression algorithms to compress your video. Motion tracking user interface and terminology overview You set up, initiate, and apply motion tracking with the Tracker panel. As with all properties, you can modify, animate, manage, and link tracking properties in the Timeline panel. You specify areas to track by setting track points in the Layer panel. Each track point contains a feature region, a search region, and an attach point. A set of track points is a tracker. Layer panel with track point A. Search region B. Feature region C. Attach point Feature region The feature region defines the element in the layer to be tracked. The feature region should surround a distinct visual element, preferably one object in the real world. After Effects must be able to clearly identify the tracked feature throughout the duration of the track, despite changes in light, background, and angle. Search region The search region defines the area that After Effects will search to locate the tracked feature. The tracked feature needs to be distinct only within the search region, not within the entire frame. Confining the search to a small search region saves search time and makes the search process easier, but runs the risk of the tracked feature leaving the search region entirely between frames. Attach point The attach point designates the place of attachment for the target -the layer or effect control point to synchronize with the moving feature in the tracked layer. Note: When you begin tracking, After Effects sets the quality of the motion source layer to Best and the resolution to Full in the Composition and