IDFT_R2C           95 libavcodec/rdft.c     s->sign_convention = trans == IDFT_R2C || trans == DFT_C2R ? 1 : -1;
IDFT_R2C          101 libavcodec/rdft.c     if ((ret = ff_fft_init(&s->fft, nbits-1, trans == IDFT_C2R || trans == IDFT_R2C)) < 0)