FreeCalypso > hg > gsm-codec-lib
view libtwamr/d1035pf.c @ 478:936a08cc73ce
doc/AMR-library-API: describe the decoder
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sun, 19 May 2024 21:32:31 +0000 |
parents | 2cf33c211544 |
children |
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/* ******************************************************************************** * * GSM AMR-NB speech codec R98 Version 7.6.0 December 12, 2001 * R99 Version 3.3.0 * REL-4 Version 4.1.0 * ******************************************************************************** * * File : d1035pf.c * Purpose : Builds the innovative codevector * ******************************************************************************** */ /* ******************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ******************************************************************************** */ #include "namespace.h" #include "d1035pf.h" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "typedef.h" #include "basic_op.h" #include "no_count.h" #include "cnst.h" #include "graytab.h" /* ******************************************************************************** * LOCAL VARIABLES AND TABLES ******************************************************************************** */ #define NB_PULSE 10 /* number of pulses */ /* ******************************************************************************** * PUBLIC PROGRAM CODE ******************************************************************************** */ /************************************************************************* * * FUNCTION: dec_10i40_35bits() * * PURPOSE: Builds the innovative codevector from the received * index of algebraic codebook. * * See c1035pf.c for more details about the algebraic codebook structure. * *************************************************************************/ void dec_10i40_35bits ( Word16 index[], /* (i) : index of 10 pulses (sign+position) */ Word16 cod[] /* (o) : algebraic (fixed) codebook excitation */ ) { Word16 i, j, pos1, pos2, sign, tmp; for (i = 0; i < L_CODE; i++) { cod[i] = 0; move16 (); } /* decode the positions and signs of pulses and build the codeword */ for (j = 0; j < NB_TRACK; j++) { /* compute index i */ tmp = index[j]; move16 (); i = tmp & 7; logic16 (); i = dgray[i]; move16 (); i = extract_l (L_shr (L_mult (i, 5), 1)); pos1 = add (i, j); /* position of pulse "j" */ i = shr (tmp, 3) & 1; logic16 (); test (); if (i == 0) { sign = 4096; move16 (); /* +1.0 */ } else { sign = -4096; move16 (); /* -1.0 */ } cod[pos1] = sign; move16 (); /* compute index i */ i = index[add (j, 5)] & 7; logic16 (); i = dgray[i]; move16 (); i = extract_l (L_shr (L_mult (i, 5), 1)); pos2 = add (i, j); /* position of pulse "j+5" */ test (); if (sub (pos2, pos1) < 0) { sign = negate (sign); } cod[pos2] = add (cod[pos2], sign); move16 (); } return; }