Patent ID: 8559510

Claim:
An image decoding apparatus which decodes image data compressed using inter picture predictive encoding, comprising: a first picture buffer that stores the compressed image data; a second picture buffer that stores decoded image data; decoding unit that decodes the compressed image data stored in said first picture buffer by referring to image data stored in said second picture buffer, as needed, and stores the decoded image data in said second picture buffer; detection unit that detects a free area of said second picture buffer; control unit that instructs said decoding unit to interrupt decoding of succeeding pictures regardless of picture type being I, P or B picture type and to delete image data which is in said second picture buffer and is not to be displayed when the free area detected by said detection unit is smaller than a predetermined value; and determination unit that determines input of IDR (Instantaneous Decoder Refresh) picture during a period in which decoding operation of said decoding unit is interrupted by said control unit, wherein said control unit restarts the decoding operation of said decoding unit from the IDR picture when presence of input of the IDR picture is determined by said determination unit.