/*

 * Copyright (C) 2003 - 2016 Sony Corporation

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include "ldac.h"

#define LDAC_TH_LOWENERGY_L _scalar(225.47)

#define LDAC_TH_LOWENERGY_M _scalar(897.61)

#define LDAC_TH_LOWENERGY_H _scalar(3573.44)

#define LDAC_TH_CENTROID    _scalar(45.0)

#define LDAC_TH_ZERODIV     _scalar(1.0e-6)

/***************************************************************************************************

    Calculate Pseudo Spectrum and Low Band Energy

***************************************************************************************************/

static SCALAR calc_mdct_pseudo_spectrum_ldac(

SCALAR *p_spec,

SCALAR *p_psd,

int n)

{

    int isp;

    SCALAR low_energy, tmp;

    SCALAR y0, y1, y2;

    {

        y1 = p_spec[0];

        y2 = p_spec[1];

        tmp = y1 * y1 + y2 * y2;

        low_energy = tmp;

        p_psd[0] = sqrt(tmp);

    }

    for (isp = 1; isp < LDAC_NSP_LOWENERGY; isp++) {

        y0 = y1;

        y1 = y2;

        y2 = p_spec[isp+1];

        tmp = y1 * y1 + (y0-y2) * (y0-y2);

        low_energy += tmp;

        p_psd[isp] = sqrt(tmp);

    }

    for (isp = LDAC_NSP_LOWENERGY; isp < n-1; isp++) {

        y0 = y1;

        y1 = y2;

        y2 = p_spec[isp+1];

        tmp = y1 * y1 + (y0-y2) * (y0-y2);

        p_psd[isp] = sqrt(tmp);

    }

    {

        tmp = y1 * y1 + y2 * y2;

        p_psd[n-1] = sqrt(tmp);

    }

    return low_energy;

}

/***************************************************************************************************

    Calculate Pseudo Spectrum Centroid

***************************************************************************************************/

static SCALAR calc_spectral_centroid_ldac(

SCALAR *p_spec,

int nsp)

{

    int isp;

    SCALAR centroid;

    SCALAR s1, s2;

    s1 = s2 = _scalar(0.0);

    for (isp = 0; isp < nsp; isp++) {

        s1 += (SCALAR)isp * *p_spec;

        s2 += *p_spec++;

    }

    if (s2 < LDAC_TH_ZERODIV) {

        centroid = _scalar(0.0);

    }

    else {

        centroid = s1 / s2;

    }

    return centroid;

}

/***************************************************************************************************

    Calculate Number of Zero Cross

***************************************************************************************************/

static int calc_zero_cross_number_ldac(

SCALAR *p_time,

int n)

{

    int i;

    int zero_cross = 0;

    SCALAR prev;

    prev = _scalar(0.0);

    for (i = 0; i < n; i++) {

        if (prev * *p_time < _scalar(0.0)) {

            zero_cross++;

        }

        prev = *p_time++;

    }

    return zero_cross;

}

/***************************************************************************************************

    Analyze Frame Status

***************************************************************************************************/

DECLSPEC int ana_frame_status_ldac(

SFINFO *p_sfinfo,

int nlnn)

{

    AC *p_ac;

    int ich;

    int nchs = p_sfinfo->cfg.ch;

    int nsmpl = npow2_ldac(nlnn+1);

    int cnt, zero_cross;

    int a_status[LDAC_PRCNCH];

    SCALAR low_energy, centroid;

    SCALAR a_psd_spec[LDAC_NSP_PSEUDOANA];

    for (ich = 0; ich < nchs; ich++) {

        p_ac = p_sfinfo->ap_ac[ich];

        low_energy = calc_mdct_pseudo_spectrum_ldac(p_ac->p_acsub->a_spec, a_psd_spec, LDAC_NSP_PSEUDOANA);

        centroid = calc_spectral_centroid_ldac(a_psd_spec, LDAC_NSP_PSEUDOANA);

        zero_cross = calc_zero_cross_number_ldac(p_ac->p_acsub->a_time, nsmpl);

        a_status[ich] = LDAC_FRMSTAT_LEV_0;

        if (low_energy < LDAC_TH_LOWENERGY_L) { 

            a_status[ich] = LDAC_FRMSTAT_LEV_3;

        }

        else {

            if (low_energy < LDAC_TH_LOWENERGY_M) {

                a_status[ich] = LDAC_FRMSTAT_LEV_2;

            }

            else if (low_energy < LDAC_TH_LOWENERGY_H) {

                a_status[ich] = LDAC_FRMSTAT_LEV_1;

            }

            cnt = p_ac->frmana_cnt;

            if ((centroid > LDAC_TH_CENTROID) && (zero_cross >= LDAC_TH_ZCROSNUM)) {

                cnt++;

                if (cnt >= LDAC_MAXCNT_FRMANA) {

                    cnt = LDAC_MAXCNT_FRMANA;

                    a_status[ich] = LDAC_FRMSTAT_LEV_2;

                }

                else if (a_status[ich] <= LDAC_FRMSTAT_LEV_1) {

                    a_status[ich]++;

                }

            }

            else {

                cnt = 0;

            }

            p_ac->frmana_cnt = cnt;

        }

    }

    if (nchs == LDAC_CHANNEL_1CH) {

        return a_status[0];

    }

    else {

        return min_ldac(a_status[0], a_status[1]);

    }

}