Picture data processor

TL;DR: In this paper, the bit number of expansion picture data X (n) outputted from a JPEG decoder is reduced in an error propagation circuit 22 and picture data Y (8n) are generated.

Abstract: PURPOSE: To reduce the capacity of a picture memory used in a picture data processor. CONSTITUTION: The bit number of expansion picture data X (n) outputted from a JPEG decoder 21 is reduced in an error propagation circuit 22 and picture data Y (8n) are generated. To the error propagation circuit 22, an error data memory 23 for storing errors generated in picture elements at the end part of one block is connected. Thus, an error propagation processing by a block unit is made possible. Then, the picture data Y (n) are alternately stored in the two memory areas 24a and 24b of the picture memory 24 by a screen unit and the picture data Y (n) stored in the memory areas 24a and 24n are alternately read and supplied to a display processor 25.