| 摘要 |
PROBLEM TO BE SOLVED: To maintain continuity between frames and enable prediction in the time region and filter processing. SOLUTION: One frame (N points) of input samples is duplicated and every two N points are taken out (11) and applied with 2 N points of window functions (12) to obtain 2N points of X(n). Then the first N/2 length of x(i) where i=0,..., N/2-1 are inversed in the order of time to be subtracted from the next N/2 of x(i) where i=N/2..., N-1 and the final N/2 length of x(i) where i=N+N/2,..., 2N-1 are inversed in the order or time to be added to immediately proceeding N/2 of x(i) where i=N,..., N+N/2-1 for pre-processing (41). After that, inverse filter processing (42) is applied to the results y(n) of this to obtain a residual signal z(n), which is Discrete Cosine Transformed(DCT) to obtain a frequency region coefficient v(k) (33) to subject to weighted quantization. |
