ENCODING AN IMAGE USING EMBEDDED ZERO BLOCK CODING ALONG WITH A DISCRETE COSINE TRANSFORMATION

摘要

An image (a still image or a frame of a video) is divided into macroblocks. The content of a macroblock is predicted based on the content of other macroblocks that are spatially or temporally close to the instant macroblock. The prediction is compared against the actual macroblock content to yield a residual value. The residual is then transformed by a discrete cosine ("DCT") transformation. The resulting DCT coefficients are grouped into subbands. The subbands are encoded using embedded zero block bitplane coding ("EZBC"), and the EZBC output is sent to a decoder (usually on a device remote from the encoder). The EZBC output is also decoded by a subband-dequantizer process whose output coefficients are fed into an inverse DCT to reconstruct the residual signal. The reconstructed residual is used to refine the coding process.