FreeCalypso > hg > gsm-codec-lib
view libtwamr/inter_36.c @ 458:e26b974f7ba3
doc/AMR-study-utils: update for the current situation
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Fri, 10 May 2024 18:45:36 +0000 |
parents | 838ed426bb76 |
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 : inter_36.c * Purpose : Interpolating the normalized correlation * : with 1/3 or 1/6 resolution. * ******************************************************************************** */ /* ******************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ******************************************************************************** */ #include "namespace.h" #include "inter_36.h" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "typedef.h" #include "basic_op.h" #include "no_count.h" #include "cnst.h" /* ******************************************************************************** * LOCAL VARIABLES AND TABLES ******************************************************************************** */ #define UP_SAMP_MAX 6 #include "inter_36.tab" /* ******************************************************************************** * PUBLIC PROGRAM CODE ******************************************************************************** */ /************************************************************************* * * FUNCTION: Interpol_3or6() * * PURPOSE: Interpolating the normalized correlation with 1/3 or 1/6 * resolution. * *************************************************************************/ Word16 Interpol_3or6 ( /* o : interpolated value */ Word16 *x, /* i : input vector */ Word16 frac, /* i : fraction (-2..2 for 3*, -3..3 for 6*) */ Word16 flag3 /* i : if set, upsampling rate = 3 (6 otherwise) */ ) { Word16 i, k; Word16 *x1, *x2; const Word16 *c1, *c2; Word32 s; test(); if (flag3 != 0) { frac = shl (frac, 1); /* inter_3[k] = inter_6[2*k] -> k' = 2*k */ } test (); if (frac < 0) { frac = add (frac, UP_SAMP_MAX); x--; } x1 = &x[0]; move16 (); x2 = &x[1]; move16 (); c1 = &inter_6[frac]; move16 (); c2 = &inter_6[sub (UP_SAMP_MAX, frac)]; move16 (); s = 0; move32 (); for (i = 0, k = 0; i < L_INTER_SRCH; i++, k += UP_SAMP_MAX) { s = L_mac (s, x1[-i], c1[k]); s = L_mac (s, x2[i], c2[k]); } return round (s); }