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      1 /*
      2  * Copyright (C) 2003 - 2016 Sony Corporation
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "ldac.h"
     18 
     19 
     20 #define LDAC_TH_LOWENERGY_L _scalar(225.47)
     21 #define LDAC_TH_LOWENERGY_M _scalar(897.61)
     22 #define LDAC_TH_LOWENERGY_H _scalar(3573.44)
     23 
     24 #define LDAC_TH_CENTROID    _scalar(45.0)
     25 #define LDAC_TH_ZERODIV     _scalar(1.0e-6)
     26 
     27 /***************************************************************************************************
     28     Calculate Pseudo Spectrum and Low Band Energy
     29 ***************************************************************************************************/
     30 static SCALAR calc_mdct_pseudo_spectrum_ldac(
     31 SCALAR *p_spec,
     32 SCALAR *p_psd,
     33 int n)
     34 {
     35     int isp;
     36     SCALAR low_energy, tmp;
     37     SCALAR y0, y1, y2;
     38 
     39     {
     40         y1 = p_spec[0];
     41         y2 = p_spec[1];
     42         tmp = y1 * y1 + y2 * y2;
     43         low_energy = tmp;
     44         p_psd[0] = sqrt(tmp);
     45     }
     46 
     47     for (isp = 1; isp < LDAC_NSP_LOWENERGY; isp++) {
     48         y0 = y1;
     49         y1 = y2;
     50         y2 = p_spec[isp+1];
     51         tmp = y1 * y1 + (y0-y2) * (y0-y2);
     52         low_energy += tmp;
     53         p_psd[isp] = sqrt(tmp);
     54     }
     55 
     56     for (isp = LDAC_NSP_LOWENERGY; isp < n-1; isp++) {
     57         y0 = y1;
     58         y1 = y2;
     59         y2 = p_spec[isp+1];
     60         tmp = y1 * y1 + (y0-y2) * (y0-y2);
     61         p_psd[isp] = sqrt(tmp);
     62     }
     63 
     64     {
     65         tmp = y1 * y1 + y2 * y2;
     66         p_psd[n-1] = sqrt(tmp);
     67     }
     68 
     69     return low_energy;
     70 }
     71 
     72 /***************************************************************************************************
     73     Calculate Pseudo Spectrum Centroid
     74 ***************************************************************************************************/
     75 static SCALAR calc_spectral_centroid_ldac(
     76 SCALAR *p_spec,
     77 int nsp)
     78 {
     79     int isp;
     80     SCALAR centroid;
     81     SCALAR s1, s2;
     82 
     83     s1 = s2 = _scalar(0.0);
     84     for (isp = 0; isp < nsp; isp++) {
     85         s1 += (SCALAR)isp * *p_spec;
     86         s2 += *p_spec++;
     87     }
     88 
     89     if (s2 < LDAC_TH_ZERODIV) {
     90         centroid = _scalar(0.0);
     91     }
     92     else {
     93         centroid = s1 / s2;
     94     }
     95 
     96     return centroid;
     97 }
     98 
     99 /***************************************************************************************************
    100     Calculate Number of Zero Cross
    101 ***************************************************************************************************/
    102 static int calc_zero_cross_number_ldac(
    103 SCALAR *p_time,
    104 int n)
    105 {
    106     int i;
    107     int zero_cross = 0;
    108     SCALAR prev;
    109 
    110     prev = _scalar(0.0);
    111     for (i = 0; i < n; i++) {
    112         if (prev * *p_time < _scalar(0.0)) {
    113             zero_cross++;
    114         }
    115         prev = *p_time++;
    116     }
    117 
    118     return zero_cross;
    119 }
    120 
    121 /***************************************************************************************************
    122     Analyze Frame Status
    123 ***************************************************************************************************/
    124 DECLSPEC int ana_frame_status_ldac(
    125 SFINFO *p_sfinfo,
    126 int nlnn)
    127 {
    128     AC *p_ac;
    129     int ich;
    130     int nchs = p_sfinfo->cfg.ch;
    131     int nsmpl = npow2_ldac(nlnn+1);
    132     int cnt, zero_cross;
    133     int a_status[LDAC_PRCNCH];
    134     SCALAR low_energy, centroid;
    135     SCALAR a_psd_spec[LDAC_NSP_PSEUDOANA];
    136 
    137     for (ich = 0; ich < nchs; ich++) {
    138         p_ac = p_sfinfo->ap_ac[ich];
    139 
    140         low_energy = calc_mdct_pseudo_spectrum_ldac(p_ac->p_acsub->a_spec, a_psd_spec, LDAC_NSP_PSEUDOANA);
    141 
    142         centroid = calc_spectral_centroid_ldac(a_psd_spec, LDAC_NSP_PSEUDOANA);
    143 
    144         zero_cross = calc_zero_cross_number_ldac(p_ac->p_acsub->a_time, nsmpl);
    145 
    146         a_status[ich] = LDAC_FRMSTAT_LEV_0;
    147         if (low_energy < LDAC_TH_LOWENERGY_L) {
    148             a_status[ich] = LDAC_FRMSTAT_LEV_3;
    149         }
    150         else {
    151             if (low_energy < LDAC_TH_LOWENERGY_M) {
    152                 a_status[ich] = LDAC_FRMSTAT_LEV_2;
    153             }
    154             else if (low_energy < LDAC_TH_LOWENERGY_H) {
    155                 a_status[ich] = LDAC_FRMSTAT_LEV_1;
    156             }
    157 
    158             cnt = p_ac->frmana_cnt;
    159             if ((centroid > LDAC_TH_CENTROID) && (zero_cross >= LDAC_TH_ZCROSNUM)) {
    160                 cnt++;
    161 
    162                 if (cnt >= LDAC_MAXCNT_FRMANA) {
    163                     cnt = LDAC_MAXCNT_FRMANA;
    164                     a_status[ich] = LDAC_FRMSTAT_LEV_2;
    165                 }
    166                 else if (a_status[ich] <= LDAC_FRMSTAT_LEV_1) {
    167                     a_status[ich]++;
    168                 }
    169             }
    170             else {
    171                 cnt = 0;
    172             }
    173             p_ac->frmana_cnt = cnt;
    174         }
    175     }
    176 
    177     if (nchs == LDAC_CHANNEL_1CH) {
    178         return a_status[0];
    179     }
    180     else {
    181         return min_ldac(a_status[0], a_status[1]);
    182     }
    183 }
    184 
    185