IMAGE CODING DEVICE, CODING RATE CONVERSION DEVICE, AUDIO VIDEO STREAM RECORDING DEVICE, NETWORK DISTRIBUTION SYSTEM, COEFFICIENT CONVERSION DEVICE, INTEGRATED CIRCUIT, AND IMAGE CODING METHOD

摘要

An image coding device (301) in an aspect of the present invention includes: a quantization unit (304) which quantizes an orthogonal transform coefficient set (217) obtained by orthogonally transforming image data (310), so as to generate a quantized coefficient set (110) that corresponds to one coded block unit; a coefficient sequence extraction unit (101) which extracts a first coefficient sequence (112) that is a part of the quantized coefficient set (110); a coefficient non-zeroing unit (102) which converts at least one of zero coefficients included in the first coefficient sequence (112) into a nonzero coefficient, so as to generate a second coefficient sequence (113) including all coefficients resulting from the conversion; a coefficient sequence selection unit (106) which selects one of the first coefficient sequence (112) and the second coefficient sequence (113), the selected one having a smaller amount of codes when coded; and a variable-length coding unit (306) which performs variable-length coding on the first coefficient sequence (112) or the second coefficient sequence (113) selected by the coefficient sequence selection unit (106), so as to generate coded image data (311).