static void decorrelation(PSContext *ps, float (*out)[32][2], const float (*s)[32][2], int is34) { float power[34][PS_QMF_TIME_SLOTS] = {{0}}; float transient_gain[34][PS_QMF_TIME_SLOTS]; float *peak_decay_nrg = ps->peak_decay_nrg; float *power_smooth = ps->power_smooth; float *peak_decay_diff_smooth = ps->peak_decay_diff_smooth; float (*delay)[PS_QMF_TIME_SLOTS + PS_MAX_DELAY][2] = ps->delay; float (*ap_delay)[PS_AP_LINKS][PS_QMF_TIME_SLOTS + PS_MAX_AP_DELAY][2] = ps->ap_delay; const int8_t *k_to_i = is34 ? k_to_i_34 : k_to_i_20; const float peak_decay_factor = 0.76592833836465f; const float transient_impact = 1.5f; const float a_smooth = 0.25f; ///< Smoothing coefficient int i, k, m, n; int n0 = 0, nL = 32; static const int link_delay[] = { 3, 4, 5 }; static const float a[] = { 0.65143905753106f, 0.56471812200776f, 0.48954165955695f }; if (is34 != ps->is34bands_old) { memset(ps->peak_decay_nrg, 0, sizeof(ps->peak_decay_nrg)); memset(ps->power_smooth, 0, sizeof(ps->power_smooth)); memset(ps->peak_decay_diff_smooth, 0, sizeof(ps->peak_decay_diff_smooth)); memset(ps->delay, 0, sizeof(ps->delay)); memset(ps->ap_delay, 0, sizeof(ps->ap_delay)); } for (n = n0; n < nL; n++) { for (k = 0; k < NR_BANDS[is34]; k++) { int i = k_to_i[k]; power[i][n] += s[k][n][0] * s[k][n][0] + s[k][n][1] * s[k][n][1]; } } //Transient detection for (i = 0; i < NR_PAR_BANDS[is34]; i++) { for (n = n0; n < nL; n++) { float decayed_peak = peak_decay_factor * peak_decay_nrg[i]; float denom; peak_decay_nrg[i] = FFMAX(decayed_peak, power[i][n]); power_smooth[i] += a_smooth * (power[i][n] - power_smooth[i]); peak_decay_diff_smooth[i] += a_smooth * (peak_decay_nrg[i] - power[i][n] - peak_decay_diff_smooth[i]); denom = transient_impact * peak_decay_diff_smooth[i]; transient_gain[i][n] = (denom > power_smooth[i]) ? power_smooth[i] / denom : 1.0f; } } //Decorrelation and transient reduction // PS_AP_LINKS - 1 // ----- // | | Q_fract_allpass[k][m]*z^-link_delay[m] - a[m]*g_decay_slope[k] //H[k][z] = z^-2 * phi_fract[k] * | | ---------------------------------------------------------------- // | | 1 - a[m]*g_decay_slope[k]*Q_fract_allpass[k][m]*z^-link_delay[m] // m = 0 //d[k][z] (out) = transient_gain_mapped[k][z] * H[k][z] * s[k][z] for (k = 0; k < NR_ALLPASS_BANDS[is34]; k++) { int b = k_to_i[k]; float g_decay_slope = 1.f - DECAY_SLOPE * (k - DECAY_CUTOFF[is34]); float ag[PS_AP_LINKS]; g_decay_slope = av_clipf(g_decay_slope, 0.f, 1.f); memcpy(delay[k], delay[k]+nL, PS_MAX_DELAY*sizeof(delay[k][0])); memcpy(delay[k]+PS_MAX_DELAY, s[k], numQMFSlots*sizeof(delay[k][0])); for (m = 0; m < PS_AP_LINKS; m++) { memcpy(ap_delay[k][m], ap_delay[k][m]+numQMFSlots, 5*sizeof(ap_delay[k][m][0])); ag[m] = a[m] * g_decay_slope; } for (n = n0; n < nL; n++) { float in_re = delay[k][n+PS_MAX_DELAY-2][0] * phi_fract[is34][k][0] - delay[k][n+PS_MAX_DELAY-2][1] * phi_fract[is34][k][1]; float in_im = delay[k][n+PS_MAX_DELAY-2][0] * phi_fract[is34][k][1] + delay[k][n+PS_MAX_DELAY-2][1] * phi_fract[is34][k][0]; for (m = 0; m < PS_AP_LINKS; m++) { float a_re = ag[m] * in_re; float a_im = ag[m] * in_im; float link_delay_re = ap_delay[k][m][n+5-link_delay[m]][0]; float link_delay_im = ap_delay[k][m][n+5-link_delay[m]][1]; float fractional_delay_re = Q_fract_allpass[is34][k][m][0]; float fractional_delay_im = Q_fract_allpass[is34][k][m][1]; ap_delay[k][m][n+5][0] = in_re; ap_delay[k][m][n+5][1] = in_im; in_re = link_delay_re * fractional_delay_re - link_delay_im * fractional_delay_im - a_re; in_im = link_delay_re * fractional_delay_im + link_delay_im * fractional_delay_re - a_im; ap_delay[k][m][n+5][0] += ag[m] * in_re; ap_delay[k][m][n+5][1] += ag[m] * in_im; } out[k][n][0] = transient_gain[b][n] * in_re; out[k][n][1] = transient_gain[b][n] * in_im; } } for (; k < SHORT_DELAY_BAND[is34]; k++) { memcpy(delay[k], delay[k]+nL, PS_MAX_DELAY*sizeof(delay[k][0])); memcpy(delay[k]+PS_MAX_DELAY, s[k], numQMFSlots*sizeof(delay[k][0])); for (n = n0; n < nL; n++) { //H = delay 14 out[k][n][0] = transient_gain[k_to_i[k]][n] * delay[k][n+PS_MAX_DELAY-14][0]; out[k][n][1] = transient_gain[k_to_i[k]][n] * delay[k][n+PS_MAX_DELAY-14][1]; } } for (; k < NR_BANDS[is34]; k++) { memcpy(delay[k], delay[k]+nL, PS_MAX_DELAY*sizeof(delay[k][0])); memcpy(delay[k]+PS_MAX_DELAY, s[k], numQMFSlots*sizeof(delay[k][0])); for (n = n0; n < nL; n++) { //H = delay 1 out[k][n][0] = transient_gain[k_to_i[k]][n] * delay[k][n+PS_MAX_DELAY-1][0]; out[k][n][1] = transient_gain[k_to_i[k]][n] * delay[k][n+PS_MAX_DELAY-1][1]; } } }