FreeCalypso > hg > gsm-codec-lib
view libtwamr/int_lsf.c @ 400:ffd48f0a2ab5
libtwamr: implement Prm2bits() like Bits2prm()
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Mon, 06 May 2024 19:34:59 +0000 |
parents | 693ea1d5cf1e |
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 : int_lsf.c * ******************************************************************************** */ /* ******************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ******************************************************************************** */ #include "namespace.h" #include "int_lsf.h" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "typedef.h" #include "basic_op.h" #include "no_count.h" #include "cnst.h" /* ******************************************************************************** * LOCAL VARIABLES AND TABLES ******************************************************************************** */ /* *--------------------------------------* * Constants (defined in cnst.h) * *--------------------------------------* * M : LSF order * *--------------------------------------* */ /* ******************************************************************************** * PUBLIC PROGRAM CODE ******************************************************************************** */ /* ************************************************************************** * * Function : Int_lsf * Purpose : Interpolates the LSFs for selected subframe * Description : The 20 ms speech frame is divided into 4 subframes. * The LSFs are interpolated at the 1st, 2nd and 3rd * subframe and only forwarded at the 4th subframe. * * |------|------|------|------| * sf1 sf2 sf3 sf4 * F0 F1 * * sf1: 3/4 F0 + 1/4 F1 sf3: 1/4 F0 + 3/4 F1 * sf2: 1/2 F0 + 1/2 F1 sf4: F1 * Returns : void * ************************************************************************** */ void Int_lsf( Word16 lsf_old[], /* i : LSF vector at the 4th SF of past frame */ Word16 lsf_new[], /* i : LSF vector at the 4th SF of present frame */ Word16 i_subfr, /* i : Pointer to current sf (equal to 0,40,80 or 120) */ Word16 lsf_out[] /* o : interpolated LSF parameters for current sf */ ) { Word16 i; if ( i_subfr == 0 ) { test (); for (i = 0; i < M; i++) { lsf_out[i] = add(sub(lsf_old[i], shr(lsf_old[i], 2)), shr(lsf_new[i], 2)); move16 (); } } else if ( sub(i_subfr, 40) == 0 ) { test (); test (); for (i = 0; i < M; i++) { lsf_out[i] = add(shr(lsf_old[i],1), shr(lsf_new[i], 1) ); move16 (); } } else if ( sub(i_subfr, 80) == 0 ) { test (); test (); test (); for (i = 0; i < M; i++) { lsf_out[i] = add(shr(lsf_old[i], 2), sub(lsf_new[i], shr(lsf_new[i], 2))); move16 (); } } else if ( sub(i_subfr, 120) == 0 ) { test (); test (); test (); test (); for (i = 0; i < M; i++) { lsf_out[i] = lsf_new[i]; move16 (); } } return; }