发明名称 |
Adaptive transform coding by selecting optimum block lengths according to variations between successive blocks |
摘要 |
Subblocks of input digital samples are stored into a buffer at frame intervals and segmented into blocks having an integral multiple of the length of the subblock. Each block is encoded into transform coefficients and stored into a memory. Each coefficient is squared and those of the squared transform coefficients which correspond to high-frequency components of the input digital samples are summed and a minimum value is detected therefrom as corresponding to an optimum block length. Those transform coefficients which correspond to the optimum block length are selected from the memory and multiplexed with a signal representative of the optimum block length. In a modification, interblock differences are detected between successive transform coefficients of equal block length and squared. Those of the squared interblock differences which correspond to equal block length are summed, producing a set of squared sums for each block length. A variation is detected between a representative squared sum of a given set and a representative squared sum of a successive set to identify a block length which corresponds to the variation as an optimum block length. |
申请公布号 |
EP0428156(B1) |
申请公布日期 |
1996.08.21 |
申请号 |
EP19900121798 |
申请日期 |
1990.11.14 |
申请人 |
NEC CORPORATION |
发明人 |
SUGIYAMA, AKIHIKO;IWADARE, MASAHIRO;NISHITANI, TAKAO |
分类号 |
G10L19/02;G10L19/022;H03M7/30;(IPC1-7):H03M7/30 |
主分类号 |
G10L19/02 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|