| 摘要 |
In a bit allocation method for use in orthogonal transform coding wherein bits are allocated to respective ones of transform coefficients, a bit allocation directed to the ith transform coefficient being expressed as b(i) (i=0, 1, ..., N-1, where N represents the number of the blocks) here, A included in equation (I) below is calculated so that b(i) satisfies equation (II) below first. Then, b(i) is calculated by equation (I). Thereby, b(i) is quantized as a function of A under a condition that a desired total number of bits is B. b(i)=Q(f(i))=Q(A+g(i))=Q(A+( l n sigma (i )<2>)/a) (I> (where f(i) is a bit allocation function without limiting b(i) to an integer, sigma (i)<2> is variance of the ith transform coefficient, Q(f(i)) is a function that uniformly quantizes f(i), and a is a specified set value) <MATH> <IMAGE> |
