[Opus] Update to v1.2.1

third_party/opus/src/silk/float/find_LTP_FLP.c

Index: third_party/opus/src/silk/float/find_LTP_FLP.c
diff --git a/third_party/opus/src/silk/float/find_LTP_FLP.c b/third_party/opus/src/silk/float/find_LTP_FLP.c
index 722999601409d3d94639226c0a1f23f19a7e4d75..f97064930e8416cfdfe952eadbb8ba74b09c8f43 100644
--- a/third_party/opus/src/silk/float/find_LTP_FLP.c
+++ b/third_party/opus/src/silk/float/find_LTP_FLP.c
@@ -33,100 +33,32 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "tuning_parameters.h"
 
 void silk_find_LTP_FLP(
-    silk_float                      b[ MAX_NB_SUBFR * LTP_ORDER ],      /* O    LTP coefs                                   */
-    silk_float                      WLTP[ MAX_NB_SUBFR * LTP_ORDER * LTP_ORDER ], /* O    Weight for LTP quantization       */
-    silk_float                      *LTPredCodGain,                     /* O    LTP coding gain                             */
-    const silk_float                r_lpc[],                            /* I    LPC residual                                */
-    const opus_int                  lag[  MAX_NB_SUBFR ],               /* I    LTP lags                                    */
-    const silk_float                Wght[ MAX_NB_SUBFR ],               /* I    Weights                                     */
+    silk_float                      XX[ MAX_NB_SUBFR * LTP_ORDER * LTP_ORDER ], /* O    Weight for LTP quantization         */
+    silk_float                      xX[ MAX_NB_SUBFR * LTP_ORDER ],     /* O    Weight for LTP quantization                 */
+    const silk_float                r_ptr[],                            /* I    LPC residual                                */
+    const opus_int                  lag[ MAX_NB_SUBFR ],                /* I    LTP lags                                    */
     const opus_int                  subfr_length,                       /* I    Subframe length                             */
-    const opus_int                  nb_subfr,                           /* I    number of subframes                         */
-    const opus_int                  mem_offset                          /* I    Number of samples in LTP memory             */
+    const opus_int                  nb_subfr                            /* I    number of subframes                         */
 )
 {
-    opus_int   i, k;
-    silk_float *b_ptr, temp, *WLTP_ptr;
-    silk_float LPC_res_nrg, LPC_LTP_res_nrg;
-    silk_float d[ MAX_NB_SUBFR ], m, g, delta_b[ LTP_ORDER ];
-    silk_float w[ MAX_NB_SUBFR ], nrg[ MAX_NB_SUBFR ], regu;
-    silk_float Rr[ LTP_ORDER ], rr[ MAX_NB_SUBFR ];
-    const silk_float *r_ptr, *lag_ptr;
+    opus_int   k;
+    silk_float *xX_ptr, *XX_ptr;
+    const silk_float *lag_ptr;
+    silk_float xx, temp;
 
-    b_ptr    = b;
-    WLTP_ptr = WLTP;
-    r_ptr    = &r_lpc[ mem_offset ];
+    xX_ptr = xX;
+    XX_ptr = XX;
     for( k = 0; k < nb_subfr; k++ ) {
         lag_ptr = r_ptr - ( lag[ k ] + LTP_ORDER / 2 );
+        silk_corrMatrix_FLP( lag_ptr, subfr_length, LTP_ORDER, XX_ptr );
+        silk_corrVector_FLP( lag_ptr, r_ptr, subfr_length, LTP_ORDER, xX_ptr );
+        xx = ( silk_float )silk_energy_FLP( r_ptr, subfr_length + LTP_ORDER );
+        temp = 1.0f / silk_max( xx, LTP_CORR_INV_MAX * 0.5f * ( XX_ptr[ 0 ] + XX_ptr[ 24 ] ) + 1.0f );
+        silk_scale_vector_FLP( XX_ptr, temp, LTP_ORDER * LTP_ORDER );
+        silk_scale_vector_FLP( xX_ptr, temp, LTP_ORDER );
 
-        silk_corrMatrix_FLP( lag_ptr, subfr_length, LTP_ORDER, WLTP_ptr );
-        silk_corrVector_FLP( lag_ptr, r_ptr, subfr_length, LTP_ORDER, Rr );
-
-        rr[ k ] = ( silk_float )silk_energy_FLP( r_ptr, subfr_length );
-        regu = 1.0f + rr[ k ] +
-            matrix_ptr( WLTP_ptr, 0, 0, LTP_ORDER ) +
-            matrix_ptr( WLTP_ptr, LTP_ORDER-1, LTP_ORDER-1, LTP_ORDER );
-        regu *= LTP_DAMPING / 3;
-        silk_regularize_correlations_FLP( WLTP_ptr, &rr[ k ], regu, LTP_ORDER );
-        silk_solve_LDL_FLP( WLTP_ptr, LTP_ORDER, Rr, b_ptr );
-
-        /* Calculate residual energy */
-        nrg[ k ] = silk_residual_energy_covar_FLP( b_ptr, WLTP_ptr, Rr, rr[ k ], LTP_ORDER );
-
-        temp = Wght[ k ] / ( nrg[ k ] * Wght[ k ] + 0.01f * subfr_length );
-        silk_scale_vector_FLP( WLTP_ptr, temp, LTP_ORDER * LTP_ORDER );
-        w[ k ] = matrix_ptr( WLTP_ptr, LTP_ORDER / 2, LTP_ORDER / 2, LTP_ORDER );
-
-        r_ptr    += subfr_length;
-        b_ptr    += LTP_ORDER;
-        WLTP_ptr += LTP_ORDER * LTP_ORDER;
-    }
-
-    /* Compute LTP coding gain */
-    if( LTPredCodGain != NULL ) {
-        LPC_LTP_res_nrg = 1e-6f;
-        LPC_res_nrg     = 0.0f;
-        for( k = 0; k < nb_subfr; k++ ) {
-            LPC_res_nrg     += rr[  k ] * Wght[ k ];
-            LPC_LTP_res_nrg += nrg[ k ] * Wght[ k ];
-        }
-
-        silk_assert( LPC_LTP_res_nrg > 0 );
-        *LTPredCodGain = 3.0f * silk_log2( LPC_res_nrg / LPC_LTP_res_nrg );
-    }
-
-    /* Smoothing */
-    /* d = sum( B, 1 ); */
-    b_ptr = b;
-    for( k = 0; k < nb_subfr; k++ ) {
-        d[ k ] = 0;
-        for( i = 0; i < LTP_ORDER; i++ ) {
-            d[ k ] += b_ptr[ i ];
-        }
-        b_ptr += LTP_ORDER;
-    }
-    /* m = ( w * d' ) / ( sum( w ) + 1e-3 ); */
-    temp = 1e-3f;
-    for( k = 0; k < nb_subfr; k++ ) {
-        temp += w[ k ];
-    }
-    m = 0;
-    for( k = 0; k < nb_subfr; k++ ) {
-        m += d[ k ] * w[ k ];
-    }
-    m = m / temp;
-
-    b_ptr = b;
-    for( k = 0; k < nb_subfr; k++ ) {
-        g = LTP_SMOOTHING / ( LTP_SMOOTHING + w[ k ] ) * ( m - d[ k ] );
-        temp = 0;
-        for( i = 0; i < LTP_ORDER; i++ ) {
-            delta_b[ i ] = silk_max_float( b_ptr[ i ], 0.1f );
-            temp += delta_b[ i ];
-        }
-        temp = g / temp;
-        for( i = 0; i < LTP_ORDER; i++ ) {
-            b_ptr[ i ] = b_ptr[ i ] + delta_b[ i ] * temp;
-        }
-        b_ptr += LTP_ORDER;
+        r_ptr  += subfr_length;
+        XX_ptr += LTP_ORDER * LTP_ORDER;
+        xX_ptr += LTP_ORDER;
     }
 }