Commit 9786a7a7 authored by sekine's avatar sekine
Browse files

Reduction of complexity for phase only correlation in stereo downmix for EVS.

parent ccf6ae2f

lib_com/options.h

+4 −0
Original line number Diff line number Diff line
@@ -151,6 +151,10 @@ 
#define FIX_I2_BWD                                      /* Issue 2: BWD fix to more quickly react to WB -> SWB/FB change */ 







/* NTT switches */

#define NTT_REDUC_COMP_POC                              /* Contribution  : Complexity reduction of phase spectrum in stereo downmix */



/* ################## End DEVELOPMENT switches ######################### */

/* clang-format on */

#endif

lib_enc/ivas_stereo_dmx_evs.c

+324 −1
Original line number Diff line number Diff line
@@ -155,7 +155,15 @@ static void calc_poc( 
    const float *s;

    float *P;

    float tmp1, tmp2, Lr, Li, Rr, Ri, gamma, igamma, iN;



#ifdef NTT_REDUC_COMP_POC

    float specPOr[L_FRAME48k / 2 + 1], specPOi[L_FRAME48k / 2]; /*real and imaginary part of spectrum*/

    float aR, aI;                                               /*real and imaginary values for searching phase angle*/

    int16_t j;

#else

    float specPOr[L_FRAME48k], specPOi[L_FRAME48k];

#endif



    float tmpPOC1[L_FRAME48k], tmpPOC2[L_FRAME48k];

    float rfft_buf[L_FRAME48k];

    int16_t step, bias;
@@ -200,6 +208,320 @@ static void calc_poc( 
        cos_max = n0;

    }



#ifdef NTT_REDUC_COMP_POC

    /*apploximation of phase angle on an unit circle without using sqrt()*/

    for ( i = 1; i < n0 / 2; i++ )

    {

        Lr = specLr[i];

        Li = specLi[i];

        Rr = specRr[i];

        Ri = specRi[i];



        i_for = i * cos_step;

        eps_cos = s[cos_max - i_for] * EPS;

        eps_sin = s[i_for] * EPS;

        Lr += ( specRr[i] * eps_cos + specRi[i] * eps_sin );

        Li += ( -specRr[i] * eps_sin + specRi[i] * eps_cos );

        Rr += ( specLr[i] * eps_cos + specLi[i] * eps_sin );

        Ri += ( -specLr[i] * eps_sin + specLi[i] * eps_cos );



        specPOr[i] = ( Lr * Rr + Li * Ri );

        specPOi[i] = ( Lr * Ri - Li * Rr );



        j = n0 - i;

        Lr = specLr[j];

        Li = specLi[j];

        Rr = specRr[j];

        Ri = specRi[j];

        Lr += ( -specRr[j] * eps_cos + specRi[j] * eps_sin );

        Li += ( -specRr[j] * eps_sin - specRi[j] * eps_cos );

        Rr += ( -specLr[j] * eps_cos + specLi[j] * eps_sin );

        Ri += ( -specLr[j] * eps_sin - specLi[j] * eps_cos );



        specPOr[j] = ( Lr * Rr + Li * Ri );

        specPOi[j] = ( Lr * Ri - Li * Rr );

    }

    {

        i = n0 / 2;

        Lr = specLr[i] + specRi[i] * EPS;

        Li = specLi[i] - specRr[i] * EPS;

        Rr = specRr[i] + specLi[i] * EPS;

        Ri = specRi[i] - specLr[i] * EPS;



        specPOr[i] = ( Lr * Rr + Li * Ri );

        specPOi[i] = ( Lr * Ri - Li * Rr );

    }

    /* complex spectrum (specPOr[i], specPOi[i]) are placed on an unit circle without using  srqt()*/

    for ( i = 1; i < 10; i++ ) /*search from 4 angles */

    {

        specPOr[i] = sign( specPOr[i] ) * 0.866f; /* low angles are more frequent for low frequency */

        specPOi[i] = sign( specPOi[i] ) * 0.5f;

    }

    for ( i = 10; i<n0>> 4; i++ ) /*search from 4 angles */

    {

        specPOr[i] = sign( specPOr[i] ) * 0.7071f; /* low accuracy is adequate for low frequency */

        specPOi[i] = sign( specPOi[i] ) * 0.7071f;

    }

    for ( i = n0 >> 4; i<n0>> 3; i++ ) /* binary search from 8 angles */

    {

        aR = fabsf( specPOr[i] );

        aI = fabsf( specPOi[i] );

        if ( aR > aI )

        {

            specPOr[i] = sign( specPOr[i] ) * 0.92388f;  /* (wnd[n0>>2]+wnd[(n0>>2)-1])*0.5f) */

            specPOi[i] = sign( specPOi[i] ) * 0.382683f; /* (wnd[n0>>2]+wnd[(n0>>2)-1])*0.5f) */

        }

        else

        {

            specPOr[i] = sign( specPOr[i] ) * 0.382683f; /* (wnd[n0>>2]+wnd[(n0>>2)-1])*0.5f) */

            specPOi[i] = sign( specPOi[i] ) * 0.92388f;  /* (wnd[(n0>>2)*3]+wnd[((n0>>2)*3)-1])*0.5f) */

        }

    }

    for ( i = n0 >> 3; i<n0>> 2; i++ ) /* binary search from 16 angles */

    {

        aR = fabsf( specPOr[i] );

        aI = fabsf( specPOi[i] );

        if ( aR > aI )

        {

            if ( aR * 0.414213f /*tanf(PI/8)*/ > aI )

            {

                specPOr[i] = sign( specPOr[i] ) * 0.980785f; /* (wnd[(n0>>3)*7]+wnd[((n0>>3)*7)-1])*0.5f */

                specPOi[i] = sign( specPOi[i] ) * 0.19509f;  /* (wnd[n0>>3]+wnd[(n0>>3)-1])*0.5f) */

            }

            else

            {

                specPOr[i] = sign( specPOr[i] ) * 0.83147f; /* (wnd[(n0>>3)*5]+wnd[((n0>>3)*5)-1])*0.5f */

                specPOi[i] = sign( specPOi[i] ) * 0.55557f; /* (wnd[(n0>>3)*3]+wnd[(n0>>3)*3-1])*0.5f */

            }

        }

        else

        {

            if ( aR > aI * 0.41421356f /*tanf(PI/8)*/ )

            {

                specPOr[i] = sign( specPOr[i] ) * 0.55557f;

                specPOi[i] = sign( specPOi[i] ) * 0.83147f;

            }

            else

            {

                specPOr[i] = sign( specPOr[i] ) * 0.19509f;

                specPOi[i] = sign( specPOi[i] ) * 0.980785f;

            }

        }

    }



    for ( i = n0 >> 2; i<n0>> 1; i++ ) /* binary search from 32 angles */

    {

        aR = fabsf( specPOr[i] );

        aI = fabsf( specPOi[i] );



        if ( aR > aI )

        {

            if ( aR * 0.4142136f /*tanf(PI/8)*/ > aI )

            {

                if ( aR * 0.19891f /*tanf(PI/16)*/ > aI )

                {

                    specPOr[i] = sign( specPOr[i] ) * 0.995185f;

                    specPOi[i] = sign( specPOi[i] ) * 0.098017f;

                }

                else

                {

                    specPOr[i] = sign( specPOr[i] ) * 0.95694f;

                    specPOi[i] = sign( specPOi[i] ) * 0.290285f;

                }

            }

            else

            {

                if ( aR * 0.66818f /*tanf(PI*3/16)*/ > aI )

                {

                    specPOr[i] = sign( specPOr[i] ) * 0.881921f;

                    specPOi[i] = sign( specPOi[i] ) * 0.471397f;

                }

                else

                {

                    specPOr[i] = sign( specPOr[i] ) * 0.77301f;

                    specPOi[i] = sign( specPOi[i] ) * 0.634393f;

                }

            }

        }

        else

        {

            if ( aR > aI * 0.4142136f /*tanf(PI/8)*/ )

            {

                if ( aR > aI * 0.668179f /*tanf(PI*3/16)*/ )

                {

                    specPOr[i] = sign( specPOr[i] ) * 0.634393f;

                    specPOi[i] = sign( specPOi[i] ) * 0.77301f;

                }

                else

                {

                    specPOr[i] = sign( specPOr[i] ) * 0.471397f;

                    specPOi[i] = sign( specPOi[i] ) * 0.881921f;

                }

            }

            else

            {

                if ( aR > aI * 0.198912f /*tanf(PI/16)*/ )

                {

                    specPOr[i] = sign( specPOr[i] ) * 0.290285f;

                    specPOi[i] = sign( specPOi[i] ) * 0.95694f;

                }

                else

                {

                    specPOr[i] = sign( specPOr[i] ) * 0.098017f;

                    specPOi[i] = sign( specPOi[i] ) * 0.995158f;

                }

            }

        }

    }



    for ( i = n0 >> 1; i < min( n0, 320 ); i++ ) /* binary search from 64 angles */

    {

        aR = fabsf( specPOr[i] );

        aI = fabsf( specPOi[i] );



        if ( aR > aI )

        {

            if ( aR * 0.414213f /*tanf(PI/8)*/ > aI )

            {

                if ( aR * 0.19891f /*tanf(PI/16)*/ > aI )

                {

                    if ( aR * 0.0984914f /*tanf(PI/32)*/ > aI )

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.99879f;

                        specPOi[i] = sign( specPOi[i] ) * 0.04907f;

                    }

                    else

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.98918f;

                        specPOi[i] = sign( specPOi[i] ) * 0.14763f;

                    }

                }

                else

                {

                    if ( aR * 0.303347f /*tanf(PI*3/32)*/ > aI )

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.970031f;

                        specPOi[i] = sign( specPOi[i] ) * 0.24298f;

                    }

                    else

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.941544f;

                        specPOi[i] = sign( specPOi[i] ) * 0.33689f;

                    }

                }

            }

            else

            {

                if ( aR * 0.66818f /*tanf(PI*3/16)*/ > aI )

                {

                    if ( aR * 0.534511f /*tanf(PI*5/32)*/ > aI )

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.903989f;

                        specPOi[i] = sign( specPOi[i] ) * 0.427555f;

                    }

                    else

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.857729f;

                        specPOi[i] = sign( specPOi[i] ) * 0.514103f;

                    }

                }

                else

                {

                    if ( aR * 0.8206788f /*tanf(PI*7/32)*/ > aI )

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.803208f;

                        specPOi[i] = sign( specPOi[i] ) * 0.595699f;

                    }

                    else

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.740951f;

                        specPOi[i] = sign( specPOi[i] ) * 0.671559f;

                    }

                }

            }

        }

        else

        {

            if ( aR > aI * 0.4142136f /*tanf(PI/8)*/ )

            {

                if ( aR > aI * 0.6681767f /*tanf(PI*3/16)*/ )

                {

                    if ( aR > aI * 0.820681f /*tanf(PI*7/32)*/ )

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.671559f;

                        specPOi[i] = sign( specPOi[i] ) * 0.740951f;

                    }

                    else

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.595699f;

                        specPOi[i] = sign( specPOi[i] ) * 0.803208f;

                    }

                }

                else

                {

                    if ( aR > aI * 0.5345111f /*tanf(PI*5/32)*/ )

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.514103f;

                        specPOi[i] = sign( specPOi[i] ) * 0.857729f;

                    }

                    else

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.427555f;

                        specPOi[i] = sign( specPOi[i] ) * 0.903989f;

                    }

                }

            }

            else

            {

                if ( aR > aI * 0.1989124f /*tanf(PI/16)*/ )

                {

                    if ( aR > aI * 0.3033467f /*tanf(PI*3/32)*/ )

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.33689f;

                        specPOi[i] = sign( specPOi[i] ) * 0.941544f;

                    }

                    else

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.24298f;

                        specPOi[i] = sign( specPOi[i] ) * 0.970031f;

                    }

                }

                else

                {

                    if ( aR > aI * 0.098491f /*tanf(PI/32)*/ )

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.14673f;

                        specPOi[i] = sign( specPOi[i] ) * 0.989177f;

                    }

                    else

                    {

                        specPOr[i] = sign( specPOr[i] ) * 0.049068f;

                        specPOi[i] = sign( specPOi[i] ) * 0.998795f;

                    }

                }

            }

        }

    }

    for ( i = 1; i < min( n0, 320 ); i++ ) /*neglect highest frequency bins when 48 kHz samplng*/

    {

        tmp1 = wnd[i * step + bias] * gamma;

        specPOr[i] *= tmp1;

        specPOi[i] *= tmp1;

        gamma -= igamma;

    }

    if ( i < n0 )

    {

        gamma -= igamma * ( n0 - 320 );

    }

    for ( /* i = min(n0, 320) */; i < n0; i++ ) /*neglect higher frequency bins when 48 kHz samplng*/

    {

        specPOr[i] = 0.f;

        specPOi[i] = 0.f;

    }

    specPOr[n0] = sign( specLr[n0] ) * sign( specRr[n0] ) * wnd[i * step + bias] * gamma;



#else



    for ( i = 1; i < n0 / 2; i++ )

    {

        Lr = specLr[i];
@@ -245,6 +567,7 @@ static void calc_poc( 
    }



    specPOr[n0] = sign( specLr[i] ) * sign( specRr[i] ) * wnd[i * step + bias] * gamma;

#endif



    rfft_buf[0] = specPOr[0];

    rfft_buf[1] = specPOr[n0];