void(* mdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input)
void(* imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input)
void(* imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input)
enum mdct_permutation_type mdct_permutation