TRANSMITTING AND RECEIVING A COMPOSITE IMAGE

摘要

For a video sequence including a composite image having a foreground image and a transparency mask, a video encoder determines whether the transparency mask is the same as a transparency mask of a preceding image. Where the transparency mask is not the same, the transparency mask is encoded as an image. The encoder then transmits the encoded foreground image, any encoded transparency mask and a flag signifying whether the encoded transparency mask for a preceding image is to be used in association with the encoded foreground image of the current image.