PITCH_MIN_PERIOD 1025 libavfilter/af_arnndn.c             PITCH_MAX_PERIOD-3*PITCH_MIN_PERIOD, &pitch_index);
PITCH_MIN_PERIOD 1028 libavfilter/af_arnndn.c     gain = remove_doubling(pitch_buf, PITCH_MAX_PERIOD, PITCH_MIN_PERIOD,