Patent ID: 7062149

Claim:
An apparatus for decompressing compressed data including a group of coded pictures having at least one Intra-coded picture, Predictive-coded pictures, and Bidirectionally-coded pictures, comprising: recording means for recording said compressed data; reading means for reading said compressed data from said recording means, decompressing means for decompressing said compressed data read by said reading means from said recording means; a frame memory portion for storing decompressed data decompressed by said decompressing means; displaying means for displaying said decompressed data stored in said frame memory portion; picture designating means for designating a coded picture; and control means for controlling said reading means to have said reading means read said coded picture designated by said picture designating means from said recording means and controlling said decompressing means to have said decompressing means decompress said coded picture read by said reading means, and in which said frame memory portion includes a first memory section for storing therein a picture decompressed by said decompressing means, and a second memory section for storing therein a picture immediately subsequent to said picture stored in said first memory section and decompressed by said decompressing means, said reading means being operative to read said Intra-coded picture, Predictive-coded pictures intervening between said Intra-coded picture and said coded picture designated by said picture designating means, and said coded picture designated by said picture designating means, said decompressing means being operative to assume two operating states including a Predictive-coded picture decompressing operating state, in which said decompressing means is operative to decompress, in sequence, said Intra-coded picture and said Predictive-coded pictures intervening between said Intra-coded picture and said coded picture designated by said picture designating means under the condition that said coded picture designated by said picture designating means is a Predictive-coded picture, and a Bidirectionally-coded picture reading operation state in which said decompressing means is operative to decompress in sequence said Intra-coded picture and said Predictive-coded pictures intervening between said Intra-coded picture and Predictive-coded picture read by said reading means immediately prior to said coded picture designated by said picture designating means, and then decompress said coded picture designated by said picture designating means on the basis of two of said Predictive-coded pictures decompressed immediately prior to said coded picture designated by said picture designating means under the condition that said coded picture designated by said picture designating means is a Bidirectionally-coded picture, and said control means is operative to control said displaying means operative to display said decompressed data stored in said frame memory portion asynchronously with the timing of said decompressing means.