xref: /frameworks/av/media/libstagefright/codecs/amrwbenc/src/dtx.c

/*
 ** Copyright 2003-2010, VisualOn, Inc.
 **
 ** 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.
 */

/***********************************************************************
*       File: dtx.c                                                    *
*                                                                      *
*       Description:DTX functions                                  *
*                                                                      *
************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include "typedef.h"
#include "basic_op.h"
#include "oper_32b.h"
#include "math_op.h"
#include "cnst.h"
#include "acelp.h"                         /* prototype of functions    */
#include "bits.h"
#include "dtx.h"
#include "log2.h"
#include "mem_align.h"

static void aver_isf_history(
        Word16 isf_old[],
        Word16 indices[],
        Word32 isf_aver[]
        );

static void find_frame_indices(
        Word16 isf_old_tx[],
        Word16 indices[],
        dtx_encState * st
        );

static Word16 dithering_control(
        dtx_encState * st
        );

/* excitation energy adjustment depending on speech coder mode used, Q7 */
static Word16 en_adjust[9] =
{
    230,                                   /* mode0 = 7k  :  -5.4dB  */
    179,                                   /* mode1 = 9k  :  -4.2dB  */
    141,                                   /* mode2 = 12k :  -3.3dB  */
    128,                                   /* mode3 = 14k :  -3.0dB  */
    122,                                   /* mode4 = 16k :  -2.85dB */
    115,                                   /* mode5 = 18k :  -2.7dB  */
    115,                                   /* mode6 = 20k :  -2.7dB  */
    115,                                   /* mode7 = 23k :  -2.7dB  */
    115                                    /* mode8 = 24k :  -2.7dB  */
};

/**************************************************************************
*
* Function    : dtx_enc_init
*
**************************************************************************/
Word16 dtx_enc_init(dtx_encState ** st, Word16 isf_init[], VO_MEM_OPERATOR *pMemOP)
{
    dtx_encState *s;

    if (st == (dtx_encState **) NULL)
    {
        fprintf(stderr, "dtx_enc_init: invalid parameter\n");
        return -1;
    }
    *st = NULL;

    /* allocate memory */
    if ((s = (dtx_encState *)mem_malloc(pMemOP, sizeof(dtx_encState), 32, VO_INDEX_ENC_AMRWB)) == NULL)
    {
        fprintf(stderr, "dtx_enc_init: can not malloc state structure\n");
        return -1;
    }
    dtx_enc_reset(s, isf_init);
    *st = s;
    return 0;
}

/**************************************************************************
*
* Function    : dtx_enc_reset
*
**************************************************************************/
Word16 dtx_enc_reset(dtx_encState * st, Word16 isf_init[])
{
    Word32 i;

    if (st == (dtx_encState *) NULL)
    {
        fprintf(stderr, "dtx_enc_reset: invalid parameter\n");
        return -1;
    }
    st->hist_ptr = 0;
    st->log_en_index = 0;

    /* Init isf_hist[] */
    for (i = 0; i < DTX_HIST_SIZE; i++)
    {
        Copy(isf_init, &st->isf_hist[i * M], M);
    }
    st->cng_seed = RANDOM_INITSEED;

    /* Reset energy history */
    Set_zero(st->log_en_hist, DTX_HIST_SIZE);

    st->dtxHangoverCount = DTX_HANG_CONST;
    st->decAnaElapsedCount = 32767;

    for (i = 0; i < 28; i++)
    {
        st->D[i] = 0;
    }

    for (i = 0; i < DTX_HIST_SIZE - 1; i++)
    {
        st->sumD[i] = 0;
    }

    return 1;
}

/**************************************************************************
*
* Function    : dtx_enc_exit
*
**************************************************************************/
void dtx_enc_exit(dtx_encState ** st, VO_MEM_OPERATOR *pMemOP)
{
    if (st == NULL || *st == NULL)
        return;
    /* deallocate memory */
    mem_free(pMemOP, *st, VO_INDEX_ENC_AMRWB);
    *st = NULL;
    return;
}


/**************************************************************************
*
* Function    : dtx_enc
*
**************************************************************************/
Word16 dtx_enc(
        dtx_encState * st,                    /* i/o : State struct                                         */
        Word16 isf[M],                        /* o   : CN ISF vector                                        */
        Word16 * exc2,                        /* o   : CN excitation                                        */
        Word16 ** prms
          )
{
    Word32 i, j;
    Word16 indice[7];
    Word16 log_en, gain, level, exp, exp0, tmp;
    Word16 log_en_int_e, log_en_int_m;
    Word32 L_isf[M], ener32, level32;
    Word16 isf_order[3];
    Word16 CN_dith;

    /* VOX mode computation of SID parameters */
    log_en = 0;
    for (i = 0; i < M; i++)
    {
        L_isf[i] = 0;
    }
    /* average energy and isf */
    for (i = 0; i < DTX_HIST_SIZE; i++)
    {
        /* Division by DTX_HIST_SIZE = 8 has been done in dtx_buffer. log_en is in Q10 */
        log_en = add(log_en, st->log_en_hist[i]);

    }
    find_frame_indices(st->isf_hist, isf_order, st);
    aver_isf_history(st->isf_hist, isf_order, L_isf);

    for (j = 0; j < M; j++)
    {
        isf[j] = (Word16)(L_isf[j] >> 3);  /* divide by 8 */
    }

    /* quantize logarithmic energy to 6 bits (-6 : 66 dB) which corresponds to -2:22 in log2(E).  */
    /* st->log_en_index = (short)( (log_en + 2.0) * 2.625 ); */

    /* increase dynamics to 7 bits (Q8) */
    log_en = (log_en >> 2);

    /* Add 2 in Q8 = 512 to get log2(E) between 0:24 */
    log_en = add(log_en, 512);

    /* Multiply by 2.625 to get full 6 bit range. 2.625 = 21504 in Q13. The result is in Q6 */
    log_en = mult(log_en, 21504);

    /* Quantize Energy */
    st->log_en_index = shr(log_en, 6);

    if(st->log_en_index > 63)
    {
        st->log_en_index = 63;
    }
    if (st->log_en_index < 0)
    {
        st->log_en_index = 0;
    }
    /* Quantize ISFs */
    Qisf_ns(isf, isf, indice);


    Parm_serial(indice[0], 6, prms);
    Parm_serial(indice[1], 6, prms);
    Parm_serial(indice[2], 6, prms);
    Parm_serial(indice[3], 5, prms);
    Parm_serial(indice[4], 5, prms);

    Parm_serial((st->log_en_index), 6, prms);

    CN_dith = dithering_control(st);
    Parm_serial(CN_dith, 1, prms);

    /* level = (float)( pow( 2.0f, (float)st->log_en_index / 2.625 - 2.0 ) );    */
    /* log2(E) in Q9 (log2(E) lies in between -2:22) */
    log_en = shl(st->log_en_index, 15 - 6);

    /* Divide by 2.625; log_en will be between 0:24  */
    log_en = mult(log_en, 12483);
    /* the result corresponds to log2(gain) in Q10 */

    /* Find integer part  */
    log_en_int_e = (log_en >> 10);

    /* Find fractional part */
    log_en_int_m = (Word16) (log_en & 0x3ff);
    log_en_int_m = shl(log_en_int_m, 5);

    /* Subtract 2 from log_en in Q9, i.e divide the gain by 2 (energy by 4) */
    /* Add 16 in order to have the result of pow2 in Q16 */
    log_en_int_e = add(log_en_int_e, 16 - 1);

    level32 = Pow2(log_en_int_e, log_en_int_m); /* Q16 */
    exp0 = norm_l(level32);
    level32 = (level32 << exp0);        /* level in Q31 */
    exp0 = (15 - exp0);
    level = extract_h(level32);            /* level in Q15 */

    /* generate white noise vector */
    for (i = 0; i < L_FRAME; i++)
    {
        exc2[i] = (Random(&(st->cng_seed)) >> 4);
    }

    /* gain = level / sqrt(ener) * sqrt(L_FRAME) */

    /* energy of generated excitation */
    ener32 = Dot_product12(exc2, exc2, L_FRAME, &exp);

    Isqrt_n(&ener32, &exp);

    gain = extract_h(ener32);

    gain = mult(level, gain);              /* gain in Q15 */

    exp = add(exp0, exp);

    /* Multiply by sqrt(L_FRAME)=16, i.e. shift left by 4 */
    exp += 4;

    for (i = 0; i < L_FRAME; i++)
    {
        tmp = mult(exc2[i], gain);         /* Q0 * Q15 */
        exc2[i] = shl(tmp, exp);
    }

    return 0;
}

/**************************************************************************
*
* Function    : dtx_buffer Purpose     : handles the DTX buffer
*
**************************************************************************/
Word16 dtx_buffer(
        dtx_encState * st,                    /* i/o : State struct                    */
        Word16 isf_new[],                     /* i   : isf vector                      */
        Word32 enr,                           /* i   : residual energy (in L_FRAME)    */
        Word16 codec_mode
        )
{
    Word16 log_en;

    Word16 log_en_e;
    Word16 log_en_m;
    st->hist_ptr = add(st->hist_ptr, 1);
    if(st->hist_ptr == DTX_HIST_SIZE)
    {
        st->hist_ptr = 0;
    }
    /* copy lsp vector into buffer */
    Copy(isf_new, &st->isf_hist[st->hist_ptr * M], M);

    /* log_en = (float)log10(enr*0.0059322)/(float)log10(2.0f);  */
    Log2(enr, &log_en_e, &log_en_m);

    /* convert exponent and mantissa to Word16 Q7. Q7 is used to simplify averaging in dtx_enc */
    log_en = shl(log_en_e, 7);             /* Q7 */
    log_en = add(log_en, shr(log_en_m, 15 - 7));

    /* Find energy per sample by multiplying with 0.0059322, i.e subtract log2(1/0.0059322) = 7.39722 The
     * constant 0.0059322 takes into account windowings and analysis length from autocorrelation
     * computations; 7.39722 in Q7 = 947  */
    /* Subtract 3 dB = 0.99658 in log2(E) = 127 in Q7. */
    /* log_en = sub( log_en, 947 + en_adjust[codec_mode] ); */

    /* Find energy per sample (divide by L_FRAME=256), i.e subtract log2(256) = 8.0  (1024 in Q7) */
    /* Subtract 3 dB = 0.99658 in log2(E) = 127 in Q7. */

    log_en = sub(log_en, add(1024, en_adjust[codec_mode]));

    /* Insert into the buffer */
    st->log_en_hist[st->hist_ptr] = log_en;
    return 0;
}

/**************************************************************************
*
* Function    : tx_dtx_handler Purpose     : adds extra speech hangover
*                                            to analyze speech on
*                                            the decoding side.
**************************************************************************/
void tx_dtx_handler(dtx_encState * st,     /* i/o : State struct           */
        Word16 vad_flag,                      /* i   : vad decision           */
        Word16 * usedMode                     /* i/o : mode changed or not    */
        )
{

    /* this state machine is in synch with the GSMEFR txDtx machine      */
    st->decAnaElapsedCount = add(st->decAnaElapsedCount, 1);

    if (vad_flag != 0)
    {
        st->dtxHangoverCount = DTX_HANG_CONST;
    } else
    {                                      /* non-speech */
        if (st->dtxHangoverCount == 0)
        {                                  /* out of decoder analysis hangover  */
            st->decAnaElapsedCount = 0;
            *usedMode = MRDTX;
        } else
        {                                  /* in possible analysis hangover */
            st->dtxHangoverCount = sub(st->dtxHangoverCount, 1);

            /* decAnaElapsedCount + dtxHangoverCount < DTX_ELAPSED_FRAMES_THRESH */
            if (sub(add(st->decAnaElapsedCount, st->dtxHangoverCount),
                        DTX_ELAPSED_FRAMES_THRESH) < 0)
            {
                *usedMode = MRDTX;
                /* if short time since decoder update, do not add extra HO */
            }
            /* else override VAD and stay in speech mode *usedMode and add extra hangover */
        }
    }

    return;
}



static void aver_isf_history(
        Word16 isf_old[],
        Word16 indices[],
        Word32 isf_aver[]
        )
{
    Word32 i, j, k;
    Word16 isf_tmp[2 * M];
    Word32 L_tmp;

    /* Memorize in isf_tmp[][] the ISF vectors to be replaced by */
    /* the median ISF vector prior to the averaging               */
    for (k = 0; k < 2; k++)
    {
        if ((indices[k] + 1) != 0)
        {
            for (i = 0; i < M; i++)
            {
                isf_tmp[k * M + i] = isf_old[indices[k] * M + i];
                isf_old[indices[k] * M + i] = isf_old[indices[2] * M + i];
            }
        }
    }

    /* Perform the ISF averaging */
    for (j = 0; j < M; j++)
    {
        L_tmp = 0;

        for (i = 0; i < DTX_HIST_SIZE; i++)
        {
            L_tmp = L_add(L_tmp, L_deposit_l(isf_old[i * M + j]));
        }
        isf_aver[j] = L_tmp;
    }

    /* Retrieve from isf_tmp[][] the ISF vectors saved prior to averaging */
    for (k = 0; k < 2; k++)
    {
        if ((indices[k] + 1) != 0)
        {
            for (i = 0; i < M; i++)
            {
                isf_old[indices[k] * M + i] = isf_tmp[k * M + i];
            }
        }
    }

    return;
}

static void find_frame_indices(
        Word16 isf_old_tx[],
        Word16 indices[],
        dtx_encState * st
        )
{
    Word32 L_tmp, summin, summax, summax2nd;
    Word16 i, j, tmp;
    Word16 ptr;

    /* Remove the effect of the oldest frame from the column */
    /* sum sumD[0..DTX_HIST_SIZE-1]. sumD[DTX_HIST_SIZE] is    */
    /* not updated since it will be removed later.           */

    tmp = DTX_HIST_SIZE_MIN_ONE;
    j = -1;
    for (i = 0; i < DTX_HIST_SIZE_MIN_ONE; i++)
    {
        j = add(j, tmp);
        st->sumD[i] = L_sub(st->sumD[i], st->D[j]);
        tmp = sub(tmp, 1);
    }

    /* Shift the column sum sumD. The element sumD[DTX_HIST_SIZE-1]    */
    /* corresponding to the oldest frame is removed. The sum of     */
    /* the distances between the latest isf and other isfs, */
    /* i.e. the element sumD[0], will be computed during this call. */
    /* Hence this element is initialized to zero.                   */

    for (i = DTX_HIST_SIZE_MIN_ONE; i > 0; i--)
    {
        st->sumD[i] = st->sumD[i - 1];
    }
    st->sumD[0] = 0;

    /* Remove the oldest frame from the distance matrix.           */
    /* Note that the distance matrix is replaced by a one-         */
    /* dimensional array to save static memory.                    */

    tmp = 0;
    for (i = 27; i >= 12; i = (Word16) (i - tmp))
    {
        tmp = add(tmp, 1);
        for (j = tmp; j > 0; j--)
        {
            st->D[i - j + 1] = st->D[i - j - tmp];
        }
    }

    /* Compute the first column of the distance matrix D            */
    /* (squared Euclidean distances from isf1[] to isf_old_tx[][]). */

    ptr = st->hist_ptr;
    for (i = 1; i < DTX_HIST_SIZE; i++)
    {
        /* Compute the distance between the latest isf and the other isfs. */
        ptr = sub(ptr, 1);
        if (ptr < 0)
        {
            ptr = DTX_HIST_SIZE_MIN_ONE;
        }
        L_tmp = 0;
        for (j = 0; j < M; j++)
        {
            tmp = sub(isf_old_tx[st->hist_ptr * M + j], isf_old_tx[ptr * M + j]);
            L_tmp = L_mac(L_tmp, tmp, tmp);
        }
        st->D[i - 1] = L_tmp;

        /* Update also the column sums. */
        st->sumD[0] = L_add(st->sumD[0], st->D[i - 1]);
        st->sumD[i] = L_add(st->sumD[i], st->D[i - 1]);
    }

    /* Find the minimum and maximum distances */
    summax = st->sumD[0];
    summin = st->sumD[0];
    indices[0] = 0;
    indices[2] = 0;
    for (i = 1; i < DTX_HIST_SIZE; i++)
    {
        if (L_sub(st->sumD[i], summax) > 0)
        {
            indices[0] = i;
            summax = st->sumD[i];
        }
        if (L_sub(st->sumD[i], summin) < 0)
        {
            indices[2] = i;
            summin = st->sumD[i];
        }
    }

    /* Find the second largest distance */
    summax2nd = -2147483647L;
    indices[1] = -1;
    for (i = 0; i < DTX_HIST_SIZE; i++)
    {
        if ((L_sub(st->sumD[i], summax2nd) > 0) && (sub(i, indices[0]) != 0))
        {
            indices[1] = i;
            summax2nd = st->sumD[i];
        }
    }

    for (i = 0; i < 3; i++)
    {
        indices[i] = sub(st->hist_ptr, indices[i]);
        if (indices[i] < 0)
        {
            indices[i] = add(indices[i], DTX_HIST_SIZE);
        }
    }

    /* If maximum distance/MED_THRESH is smaller than minimum distance */
    /* then the median ISF vector replacement is not performed         */
    tmp = norm_l(summax);
    summax = (summax << tmp);
    summin = (summin << tmp);
    L_tmp = L_mult(voround(summax), INV_MED_THRESH);
    if(L_tmp <= summin)
    {
        indices[0] = -1;
    }
    /* If second largest distance/MED_THRESH is smaller than     */
    /* minimum distance then the median ISF vector replacement is    */
    /* not performed                                                 */
    summax2nd = L_shl(summax2nd, tmp);
    L_tmp = L_mult(voround(summax2nd), INV_MED_THRESH);
    if(L_tmp <= summin)
    {
        indices[1] = -1;
    }
    return;
}

static Word16 dithering_control(
        dtx_encState * st
        )
{
    Word16 tmp, mean, CN_dith, gain_diff;
    Word32 i, ISF_diff;

    /* determine how stationary the spectrum of background noise is */
    ISF_diff = 0;
    for (i = 0; i < 8; i++)
    {
        ISF_diff = L_add(ISF_diff, st->sumD[i]);
    }
    if ((ISF_diff >> 26) > 0)
    {
        CN_dith = 1;
    } else
    {
        CN_dith = 0;
    }

    /* determine how stationary the energy of background noise is */
    mean = 0;
    for (i = 0; i < DTX_HIST_SIZE; i++)
    {
        mean = add(mean, st->log_en_hist[i]);
    }
    mean = (mean >> 3);
    gain_diff = 0;
    for (i = 0; i < DTX_HIST_SIZE; i++)
    {
        tmp = abs_s(sub(st->log_en_hist[i], mean));
        gain_diff = add(gain_diff, tmp);
    }
    if (gain_diff > GAIN_THR)
    {
        CN_dith = 1;
    }
    return CN_dith;
}