Autodesk 64006-051108-9001 User Guide - Page 77

The Image Tab 69 Static Mask The Static Mask filter uses a mask to define static zones in the video and then composites the first frame of the movie into every frame of the movie in these areas. This eliminates video noise in areas that should not change and improves encoding. This filter is very specialized and is only used in special cases. You should use the Noise Reduction filters with most material. The best reason to use a static mask on an area that is not changing is that static parts of the video still have some video noise. Depending on how noisy the signal is, the changes in these static areas can be significant. The static mask prevents all pixels in the defined areas from changing, which will improve the ability of the codec to encode the overall image. This filter can also be useful for removing distracting motion in the video, such as a movement outside a window during an interview. Note: Unless you want unusual effects, only use the Static Mask with movies that contain areas that are unchanging throughout the entire clip and have no edits, no video fades to/from black, and no camera movement. To use the Static Mask filter, you must create a grayscale mask image with an image editing application. The Static Mask filter composites the first frame of the movie into every frame of the movie using a mask image. Areas that are 100% white are entirely composited from the first frame whereas areas that are 100% black are not composited at all. Use shades of gray and feathered edges to blend between the first frame and the rest of the movie. To create a static mask: 1. Copy the first frame from the movie. 2. Paste it into a new file in your image editing software. 3. In a graphics application that supports layers, create a new layer above the frame. 4. Paint the areas that are not static with a black brush. Do not make mask edges too close to a changing subject. A subject that moves into the defined zone is cut off. 5. Turn off the layer that contains the frame from the movie and use Save As to create the mask image. Save the mask image as an uncompressed PICT file at 72 ppi. 6. Click the check box next to the Static Mask filter to activate it. 7. Click Set. 8. Find the static mask file and click OK. 9. Process as normal. Note: The Static Mask filter preprocesses the image prior to encoding; the selected codec does the actual encoding of your image. Many codecs generate new keyframes in such a way that even areas that are identical throughout the whole movie may change slightly during