Patent ID: 7688890

Claim:
An image data compression device to compress image data, comprising: a quantization part quantizing the image data with a quantization step that varies based on a quantization parameter; a FIFO buffer part buffering quantized data of a plurality of frames which are quantized by the quantization part; a coded data formation part reading out the quantized data from the FIFO buffer part asynchronously with a writing to the FIFO buffer part and generating coded data by encoding the quantized data; a rate control part controlling a data size of the coded data by changing the quantization step of the quantization part by frames, calculating a predicted data size of the coded data of a previous frame from a data size of the quantized data of the previous frame and calculating the quantization parameter by using the predicted data size; and a frame skip part performing a skip process to skip a generation process of the image data that is supplied to the quantization part and performing the skip process if a frame, in which the quantization parameter becomes larger than a skip threshold, appears consecutively in a number of times which is equal or more than the number of a skip succession threshold.