Line data    Source code

       1             : /*====================================================================================
       2             :     EVS Codec 3GPP TS26.452 Aug 12, 2021. Version 16.3.0
       3             :   ====================================================================================*/
       4             : #include <stdint.h>
       5             : #include "options.h" /* Compilation switches                   */
       6             : #include "cnst.h"
       7             : #include "prot_fx.h"     /* Function prototypes                    */
       8             : #include "prot_fx_enc.h" /* Function prototypes                    */
       9             : 
      10             : /*------------------------------------------------------------------------
      11             :  * RE8_cod:
      12             :  *
      13             :  * MULTI-RATE INDEXING OF A POINT y in THE LATTICE RE8 (INDEX COMPUTATION)
      14             :  * note: the index I is defined as a 32-bit word, but only
      15             :  *       16 bits are required (long can be replaced by unsigned integer)
      16             :  *--------------------------------------------------------------------------*/
      17             : 
      18     1907653 : void re8_cod_fx(
      19             :     Word16 x[], /* i  : point in RE8 (8-dimensional integer vector)                         Q0*/
      20             :     Word16 *n,  /* i  : codebook number (*n is an integer defined in {0,2,3,4,..,n_max})    Q0*/
      21             :     UWord16 *I, /* o  : index of c (pointer to unsigned 16-bit word)                        Q0*/
      22             :     Word16 k[]  /* o  : index of v (8-dimensional vector of binary indices) = Voronoi index Q0*/
      23             : )
      24             : {
      25             :     Word16 ka_fx, c_fx[8];
      26             :     /*----------------------------------------------------------------------
      27             :      * decompose x as x = 2^r c + v, where r is an integer >=0, c is an element
      28             :      *  of Q0, Q2, Q3 or Q4, and v is an element of a Voronoi code in RE8
      29             :      *  (if r=0, x=c)
      30             :      *  this decomposition produces as a side-product the index k[] of v
      31             :      *  and the identifier ka of the absolute leader related to c
      32             :      *
      33             :      *  the index of y is split into 2 parts :
      34             :      *  - the index I of c
      35             :      *  - the index k[] of v
      36             :      ----------------------------------------------------------------------*/
      37     1907653 :     re8_vor_fx( x, n, k, c_fx, &ka_fx );
      38             : 
      39             :     /* safeguard in case that the AVQ subquantizer is not found - might happen for extremely strong onsets at the end of the frame */
      40     1907653 :     IF( GE_16( ka_fx, NB_LEADER ) )
      41             :     {
      42      200522 :         *n = 0;
      43      200522 :         move16();
      44      200522 :         set16_fx( x, 0, 8 );
      45             :     }
      46             : 
      47             :     /* compute the index I (only if c is in Q2, Q3 or Q4) */
      48     1907653 :     IF( *n > 0 )
      49             :     {
      50     1707131 :         re8_compute_base_index_fx( c_fx, ka_fx, I );
      51             :     }
      52             : 
      53     1907653 :     return;
      54             : }