FreeCalypso > hg > gsm-codec-lib
view libtwamr/int_lpc.c @ 434:ba5031723ab6
implement amrefr-tseq-enc test program
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Wed, 08 May 2024 02:17:08 +0000 |
parents | 32bc48faec4b |
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_lpc.c * ******************************************************************************** */ /* ******************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ******************************************************************************** */ #include "namespace.h" #include "int_lpc.h" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "typedef.h" #include "basic_op.h" #include "no_count.h" #include "cnst.h" #include "lsp_az.h" /* ******************************************************************************** * LOCAL VARIABLES AND TABLES ******************************************************************************** */ /* *--------------------------------------* * Constants (defined in cnst.h) * *--------------------------------------* * M : LPC order * * MP1 : LPC order + 1 * *--------------------------------------* */ /* ******************************************************************************** * PUBLIC PROGRAM CODE ******************************************************************************** */ /* ************************************************************************** * * Function : Int_lpc_1and3 * Purpose : Interpolates the LSPs and converts to LPC parameters * to get a different LP filter in each subframe. * Description : The 20 ms speech frame is divided into 4 subframes. * The LSPs are quantized and transmitted at the 2nd and * 4th subframes (twice per frame) and interpolated at the * 1st and 3rd subframe. * * |------|------|------|------| * sf1 sf2 sf3 sf4 * F0 Fm F1 * * sf1: 1/2 Fm + 1/2 F0 sf3: 1/2 F1 + 1/2 Fm * sf2: Fm sf4: F1 * Returns : void * ************************************************************************** */ void Int_lpc_1and3 ( Word16 lsp_old[], /* i : LSP vector at the 4th subfr. of past frame (M) */ Word16 lsp_mid[], /* i : LSP vector at the 2nd subfr. of present frame (M) */ Word16 lsp_new[], /* i : LSP vector at the 4th subfr. of present frame (M) */ Word16 Az[] /* o : interpolated LP parameters in all subfr. (AZ_SIZE) */ ) { Word16 i; Word16 lsp[M]; /* lsp[i] = lsp_mid[i] * 0.5 + lsp_old[i] * 0.5 */ for (i = 0; i < M; i++) { lsp[i] = add (shr (lsp_mid[i], 1), shr (lsp_old[i], 1)); move16 (); } Lsp_Az (lsp, Az); /* Subframe 1 */ Az += MP1; move16 (); Lsp_Az (lsp_mid, Az); /* Subframe 2 */ Az += MP1; move16 (); for (i = 0; i < M; i++) { lsp[i] = add (shr (lsp_mid[i], 1), shr (lsp_new[i], 1)); move16 (); } Lsp_Az (lsp, Az); /* Subframe 3 */ Az += MP1; move16 (); Lsp_Az (lsp_new, Az); /* Subframe 4 */ return; } /* ************************************************************************** * * Function : Int_lpc_1and3_2 * Purpose : Interpolation of the LPC parameters. Same as the Int_lpc * function but we do not recompute Az() for subframe 2 and * 4 because it is already available. * Returns : void * ************************************************************************** */ void Int_lpc_1and3_2 ( Word16 lsp_old[], /* i : LSP vector at the 4th subfr. of past frame (M) */ Word16 lsp_mid[], /* i : LSP vector at the 2nd subframe of present frame (M) */ Word16 lsp_new[], /* i : LSP vector at the 4th subframe of present frame (M) */ Word16 Az[] /* o :interpolated LP parameters in subframes 1 and 3 (AZ_SIZE) */ ) { Word16 i; Word16 lsp[M]; /* lsp[i] = lsp_mid[i] * 0.5 + lsp_old[i] * 0.5 */ for (i = 0; i < M; i++) { lsp[i] = add (shr (lsp_mid[i], 1), shr (lsp_old[i], 1)); move16 (); } Lsp_Az (lsp, Az); /* Subframe 1 */ Az += MP1 * 2; move16 (); for (i = 0; i < M; i++) { lsp[i] = add (shr (lsp_mid[i], 1), shr (lsp_new[i], 1)); move16 (); } Lsp_Az (lsp, Az); /* Subframe 3 */ return; } /************************************************************************* * * FUNCTION: Int_lpc_1to3() * * PURPOSE: Interpolates the LSPs and convert to LP parameters to get * a different LP filter in each subframe. * * DESCRIPTION: * The 20 ms speech frame is divided into 4 subframes. * The LSPs are quantized and transmitted at the 4th subframe * (once per frame) and interpolated at the 1st, 2nd and 3rd 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 * *************************************************************************/ void Int_lpc_1to3( Word16 lsp_old[], /* input : LSP vector at the 4th SF of past frame */ Word16 lsp_new[], /* input : LSP vector at the 4th SF of present frame */ Word16 Az[] /* output: interpolated LP parameters in all SFs */ ) { Word16 i; Word16 lsp[M]; for (i = 0; i < M; i++) { lsp[i] = add(shr(lsp_new[i], 2), sub(lsp_old[i], shr(lsp_old[i], 2))); move16 (); } Lsp_Az(lsp, Az); /* Subframe 1 */ Az += MP1; move16 (); for (i = 0; i < M; i++) { lsp[i] = add(shr(lsp_old[i], 1), shr(lsp_new[i], 1)); move16 (); } Lsp_Az(lsp, Az); /* Subframe 2 */ Az += MP1; move16 (); for (i = 0; i < M; i++) { lsp[i] = add(shr(lsp_old[i], 2), sub(lsp_new[i], shr(lsp_new[i], 2))); move16 (); } Lsp_Az(lsp, Az); /* Subframe 3 */ Az += MP1; move16 (); Lsp_Az(lsp_new, Az); /* Subframe 4 */ return; } /************************************************************************* * Function Int_lpc_1to3_2() * Interpolation of the LPC parameters. * Same as the previous function but we do not recompute Az() for * subframe 4 because it is already available. *************************************************************************/ void Int_lpc_1to3_2( Word16 lsp_old[], /* input : LSP vector at the 4th SF of past frame */ Word16 lsp_new[], /* input : LSP vector at the 4th SF of present frame */ Word16 Az[] /* output: interpolated LP parameters in SFs 1,2,3 */ ) { Word16 i; Word16 lsp[M]; for (i = 0; i < M; i++) { lsp[i] = add(shr(lsp_new[i], 2), sub(lsp_old[i], shr(lsp_old[i], 2))); move16 (); } Lsp_Az(lsp, Az); /* Subframe 1 */ Az += MP1; move16 (); for (i = 0; i < M; i++) { lsp[i] = add(shr(lsp_old[i], 1), shr(lsp_new[i], 1)); move16 (); } Lsp_Az(lsp, Az); /* Subframe 2 */ Az += MP1; move16 (); for (i = 0; i < M; i++) { lsp[i] = add(shr(lsp_old[i], 2), sub(lsp_new[i], shr(lsp_new[i], 2))); move16 (); } Lsp_Az(lsp, Az); /* Subframe 3 */ return; }