Using the maximum frequency response of pitch taps instead of maxabs

silk/VQ_WMat_EC.c

@@ -39,6 +39,7 @@ void silk_VQ_WMat_EC(
     const opus_int16            *in_Q14,                        /* I    input vector to be quantized                */
     const opus_int32            *W_Q18,                         /* I    weighting matrix                            */
     const opus_int8             *cb_Q7,                         /* I    codebook                                    */
+    const opus_uint8            *cb_gain_Q7,                    /* I    codebook effective gain                     */
     const opus_uint8            *cl_Q5,                         /* I    code length for each codebook vector        */
     const opus_int              mu_Q9,                          /* I    tradeoff betw. weighted error and rate      */
     const opus_int32            max_gain_Q7,                    /* I    maximum sum of absolute LTP coefficients    */
@@ -54,11 +55,7 @@ void silk_VQ_WMat_EC(
     *rate_dist_Q14 = silk_int32_MAX;
     cb_row_Q7 = cb_Q7;
     for( k = 0; k < L; k++ ) {
-		gain_tmp_Q7 = silk_abs( cb_row_Q7[ 0 ] ) + 
-			          silk_abs( cb_row_Q7[ 1 ] ) + 
-				      silk_abs( cb_row_Q7[ 2 ] ) + 
-				      silk_abs( cb_row_Q7[ 3 ] ) + 
-				      silk_abs( cb_row_Q7[ 4 ] );
+	    gain_tmp_Q7 = cb_gain_Q7[k];
 
         diff_Q14[ 0 ] = in_Q14[ 0 ] - silk_LSHIFT( cb_row_Q7[ 0 ], 7 );
         diff_Q14[ 1 ] = in_Q14[ 1 ] - silk_LSHIFT( cb_row_Q7[ 1 ], 7 );

silk/main.h

@@ -219,6 +219,7 @@ void silk_VQ_WMat_EC(
     const opus_int16            *in_Q14,                        /* I    input vector to be quantized                */
     const opus_int32            *W_Q18,                         /* I    weighting matrix                            */
     const opus_int8             *cb_Q7,                         /* I    codebook                                    */
+    const opus_uint8            *cb_gain_Q7,                    /* I    codebook effective gain                     */
     const opus_uint8            *cl_Q5,                         /* I    code length for each codebook vector        */
     const opus_int              mu_Q9,                          /* I    tradeoff betw. weighted error and rate      */
     const opus_int32            max_gain_Q7,                    /* I    maximum sum of absolute LTP coefficients    */

silk/quant_LTP_gains.c

@@ -47,6 +47,7 @@ void silk_quant_LTP_gains(
     opus_int8            temp_idx[ MAX_NB_SUBFR ];
     const opus_uint8     *cl_ptr_Q5;
     const opus_int8      *cbk_ptr_Q7;
+    const opus_uint8     *cbk_gain_ptr_Q7;
     const opus_int16     *b_Q14_ptr;
     const opus_int32     *W_Q18_ptr;
     opus_int32           rate_dist_Q14_subfr, rate_dist_Q14, min_rate_dist_Q14;
@@ -61,6 +62,7 @@ void silk_quant_LTP_gains(
     for( k = 0; k < 3; k++ ) {
         cl_ptr_Q5  = silk_LTP_gain_BITS_Q5_ptrs[ k ];
         cbk_ptr_Q7 = silk_LTP_vq_ptrs_Q7[        k ];
+        cbk_gain_ptr_Q7 = silk_LTP_vq_gain_ptrs_Q7[ k ];
         cbk_size   = silk_LTP_vq_sizes[          k ];
 
         /* Set up pointer to first subframe */
@@ -80,6 +82,7 @@ void silk_quant_LTP_gains(
                 b_Q14_ptr,              /* I    input vector to be quantized                            */
                 W_Q18_ptr,              /* I    weighting matrix                                        */
                 cbk_ptr_Q7,             /* I    codebook                                                */
+                cbk_gain_ptr_Q7,        /* I    codebook effective gains                                */
                 cl_ptr_Q5,              /* I    code length for each codebook vector                    */
                 mu_Q9,                  /* I    tradeoff between weighted error and rate                */
 				max_gain_Q7,            /* I    maximum sum of absolute LTP coefficients                */

silk/tables.h

@@ -78,6 +78,8 @@ extern const opus_uint8  * const silk_LTP_gain_iCDF_ptrs[ NB_LTP_CBKS ];
 extern const opus_uint8  * const silk_LTP_gain_BITS_Q5_ptrs[ NB_LTP_CBKS ];                         /*   3 */
 extern const opus_int16  silk_LTP_gain_middle_avg_RD_Q14;
 extern const opus_int8   * const silk_LTP_vq_ptrs_Q7[ NB_LTP_CBKS ];                                /* 168 */
+extern const opus_uint8  * const silk_LTP_vq_gain_ptrs_Q7[NB_LTP_CBKS];
+
 extern const opus_int8   silk_LTP_vq_sizes[ NB_LTP_CBKS ];                                          /*   3 */
 
 extern const opus_uint8  silk_LTPscale_iCDF[ 3 ];                                                   /*   4 */

silk/tables_LTP.c

@@ -267,6 +267,30 @@ const opus_int8 * const silk_LTP_vq_ptrs_Q7[NB_LTP_CBKS] = {
     (opus_int8 *)&silk_LTP_gain_vq_2[0][0]
 };
 
+/* Maximum frequency-dependent response of the pitch taps above,
+   computed as max(abs(freqz(taps))) */
+static const opus_uint8 silk_LTP_gain_vq_0_gain[8] = {
+      46,      2,     90,     87,     93,     91,     82,     98
+};
+
+static const opus_uint8 silk_LTP_gain_vq_1_gain[16] = {
+     109,    120,    118,     12,    113,    115,    117,    119,
+      99,     59,     87,    111,     63,    111,    112,     80
+};
+
+static const opus_uint8 silk_LTP_gain_vq_2_gain[32] = {
+     126,    124,    125,    124,    129,    121,    126,     23,
+     132,    127,    127,    127,    126,    127,    122,    133,
+     130,    134,    101,    118,    119,    145,    126,     86,
+     124,    120,    123,    119,    170,    173,    107,    109
+};
+
+const opus_uint8 * const silk_LTP_vq_gain_ptrs_Q7[NB_LTP_CBKS] = {
+    &silk_LTP_gain_vq_0_gain[0],
+    &silk_LTP_gain_vq_1_gain[0],
+    &silk_LTP_gain_vq_2_gain[0]
+};
+
 const opus_int8 silk_LTP_vq_sizes[NB_LTP_CBKS] = {
     8, 16, 32
 };