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***************************************************************************************************/
30static SCALAR calc_mdct_pseudo_spectrum_ldac(
31SCALAR *p_spec,
32SCALAR *p_psd,
33int 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***************************************************************************************************/
75static SCALAR calc_spectral_centroid_ldac(
76SCALAR *p_spec,
77int 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***************************************************************************************************/
102static int calc_zero_cross_number_ldac(
103SCALAR *p_time,
104int 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***************************************************************************************************/
124DECLSPEC int ana_frame_status_ldac(
125SFINFO *p_sfinfo,
126int 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