Patent ID: 6724816
Filing Date: 2004-04-20
Classification: G06T,H04N

Abstract:
An apparatus for receiving motion pictures having an external memory and a video decoder for restoring original pixel values after a variable length decoding process, an inverse quantization, an IDCT process, and a motion compensation process of video bit stream in a macro-block units, comprising:a compression unit which divides a decoded macro-block into a plurality of sub-blocks, and compresses decoded pixel values in each sub-block to store in said external memory; a decompression unit which reads the compressed pixel value from said external memory and restores the compressed pixel values to an original pixel value in a macro-block units; and a memory control unit which controls compression and reconstruction of pixel values, and controls storage of said pixel values in said external memory, wherein said compression unit comprises: a deviation calculation unit which calculates a standard deviation of the decoded pixel values for each sub-block; a buffer which temporarily stores the decoded pixel values in a macro-block unit and outputs the decoded pixels in sub-block units; an ADPCM compression unit which outputs first rows of each sub-block output from said buffer as original pixel values without compression, codes a difference between a prediction value and a current pixel value with respect to each remaining rows of each sub-block, and adjusts a quantization interval using the standard deviation when performing the coding; and a write FIFO which temporarily stores an output of said ADPCM compression unit, and conforms the video decoder to a data rate of said external memory.