process_get_band_noise  520 libavfilter/af_afftdn.c     band_noise = process_get_band_noise(s, dnch, 0);
process_get_band_noise  531 libavfilter/af_afftdn.c             band_noise = process_get_band_noise(s, dnch, k);
process_get_band_noise  541 libavfilter/af_afftdn.c         dnch->noise_band_auto_var[i] = s->max_var * exp((process_get_band_noise(s, dnch, i) - 2.0) * C);