FreeCalypso > hg > gsm-codec-lib
view libtwamr/c2_9pf.c @ 581:e2d5cad04cbf
libgsmhr1 RxFE: store CN R0+LPC separately from speech
In the original GSM 06.06 code the ECU for speech mode is entirely
separate from the CN generator, maintaining separate state. (The
main intertie between them is the speech vs CN state variable,
distinguishing between speech and CN BFIs, in addition to the
CN-specific function of distinguishing between initial and update
SIDs.)
In the present RxFE implementation I initially thought that we could
use the same saved_frame buffer for both ECU and CN, overwriting
just the first 4 params (R0 and LPC) when a valid SID comes in.
However, I now realize it was a bad idea: the original code has a
corner case (long sequence of speech-mode BFIs to put the ECU in
state 6, then SID and CN-mode BFIs, then a good speech frame) that
would be broken by that buffer reuse approach. We could eliminate
this corner case by resetting the ECU state when passing through
a CN insertion period, but doing so would needlessly increase
the behavioral diffs between GSM 06.06 and our version.
Solution: use a separate CN-specific buffer for CN R0+LPC parameters,
and match the behavior of GSM 06.06 code in this regard.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Thu, 13 Feb 2025 10:02:45 +0000 |
| parents | ee64aabcc7a0 |
| 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 : c2_9pf.c * Purpose : Searches a 9 bit algebraic codebook containing * 2 pulses in a frame of 40 samples. * ***************************************************************************** */ /* ***************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ***************************************************************************** */ #include "namespace.h" #include "c2_9pf.h" /* ***************************************************************************** * INCLUDE FILES ***************************************************************************** */ #include "typedef.h" #include "basic_op.h" #include "no_count.h" #include "inv_sqrt.h" #include "cnst.h" #include "cor_h.h" #include "set_sign.h" /* ***************************************************************************** * LOCAL VARIABLES AND TABLES ***************************************************************************** */ #define NB_PULSE 2 #include "c2_9pf.tab" /* ***************************************************************************** * DECLARATION OF PROTOTYPES ***************************************************************************** */ static void search_2i40( Word16 subNr, /* i : subframe number */ Word16 dn[], /* i : correlation between target and h[] */ Word16 rr[][L_CODE],/* i : matrix of autocorrelation */ Word16 codvec[] /* o : algebraic codebook vector */ ); static Word16 build_code( Word16 subNr, /* i : subframe number */ Word16 codvec[], /* i : algebraic codebook vector */ Word16 dn_sign[], /* i : sign of dn[] */ Word16 cod[], /* o : algebraic (fixed) codebook excitation */ Word16 h[], /* i : impulse response of weighted synthesis filter */ Word16 y[], /* o : filtered fixed codebook excitation */ Word16 sign[] /* o : sign of 2 pulses */ ); /* ***************************************************************************** * PUBLIC PROGRAM CODE ***************************************************************************** */ /************************************************************************* * * FUNCTION: code_2i40_9bits() * * PURPOSE: Searches a 9 bit algebraic codebook containing 2 pulses * in a frame of 40 samples. * * DESCRIPTION: * The code length is 40, containing 2 nonzero pulses: i0...i1. * All pulses can have two possible amplitudes: +1 or -1. * Pulse i0 can have 8 possible positions, pulse i1 can have * 8 positions. Also coded is which track pair should be used, * i.e. first or second pair. Where each pair contains 2 tracks. * * First subframe: * first i0 : 0, 5, 10, 15, 20, 25, 30, 35. * i1 : 2, 7, 12, 17, 22, 27, 32, 37. * second i0 : 1, 6, 11, 16, 21, 26, 31, 36. * i1 : 3, 8, 13, 18, 23, 28, 33, 38. * * Second subframe: * first i0 : 0, 5, 10, 15, 20, 25, 30, 35. * i1 : 3, 8, 13, 18, 23, 28, 33, 38. * second i0 : 2, 7, 12, 17, 22, 27, 32, 37. * i1 : 4, 9, 14, 19, 24, 29, 34, 39. * * Third subframe: * first i0 : 0, 5, 10, 15, 20, 25, 30, 35. * i1 : 2, 7, 12, 17, 22, 27, 32, 37. * second i0 : 1, 6, 11, 16, 21, 26, 31, 36. * i1 : 4, 9, 14, 19, 24, 29, 34, 39. * * Fourth subframe: * first i0 : 0, 5, 10, 15, 20, 25, 30, 35. * i1 : 3, 8, 13, 18, 23, 28, 33, 38. * second i0 : 1, 6, 11, 16, 21, 26, 31, 36. * i1 : 4, 9, 14, 19, 24, 29, 34, 39. * *************************************************************************/ Word16 code_2i40_9bits( Word16 subNr, /* i : subframe number */ Word16 x[], /* i : target vector */ Word16 h[], /* i : impulse response of weighted synthesis filter */ /* h[-L_subfr..-1] must be set to zero. */ Word16 T0, /* i : Pitch lag */ Word16 pitch_sharp, /* i : Last quantized pitch gain */ Word16 code[], /* o : Innovative codebook */ Word16 y[], /* o : filtered fixed codebook excitation */ Word16 * sign /* o : Signs of 2 pulses */ ) { Word16 codvec[NB_PULSE]; Word16 dn[L_CODE], dn2[L_CODE], dn_sign[L_CODE]; Word16 rr[L_CODE][L_CODE]; Word16 i, index, sharp; sharp = shl(pitch_sharp, 1); test (); if (sub(T0, L_CODE) < 0) for (i = T0; i < L_CODE; i++) { h[i] = add(h[i], mult(h[i - T0], sharp)); move16 (); } cor_h_x(h, x, dn, 1); set_sign(dn, dn_sign, dn2, 8); /* dn2[] not used in this codebook search */ cor_h(h, dn_sign, rr); search_2i40(subNr, dn, rr, codvec); move16 (); /* function result */ index = build_code(subNr, codvec, dn_sign, code, h, y, sign); /*-----------------------------------------------------------------* * Compute innovation vector gain. * * Include fixed-gain pitch contribution into code[]. * *-----------------------------------------------------------------*/ test (); if (sub(T0, L_CODE) < 0) for (i = T0; i < L_CODE; i++) { code[i] = add(code[i], mult(code[i - T0], sharp)); move16 (); } return index; } /* ***************************************************************************** * PRIVATE PROGRAM CODE ***************************************************************************** */ /************************************************************************* * * FUNCTION search_2i40() * * PURPOSE: Search the best codevector; determine positions of the 2 pulses * in the 40-sample frame. * *************************************************************************/ #define _1_2 (Word16)(32768L/2) #define _1_4 (Word16)(32768L/4) #define _1_8 (Word16)(32768L/8) #define _1_16 (Word16)(32768L/16) static void search_2i40( Word16 subNr, /* i : subframe number */ Word16 dn[], /* i : correlation between target and h[] */ Word16 rr[][L_CODE], /* i : matrix of autocorrelation */ Word16 codvec[] /* o : algebraic codebook vector */ ) { Word16 i0, i1; Word16 ix = 0; /* initialization only needed to keep gcc silent */ Word16 track1, ipos[NB_PULSE]; Word16 psk, ps0, ps1, sq, sq1; Word16 alpk, alp, alp_16; Word32 s, alp0, alp1; Word16 i; psk = -1; move16 (); alpk = 1; move16 (); for (i = 0; i < NB_PULSE; i++) { codvec[i] = i; move16 (); } for (track1 = 0; track1 < 2; track1++) { /* fix starting position */ ipos[0] = startPos[subNr*2+8*track1]; move16 (); ipos[1] = startPos[subNr*2+1+8*track1]; move16 (); /*----------------------------------------------------------------* * i0 loop: try 8 positions. * *----------------------------------------------------------------*/ move16 (); /* account for ptr. init. (rr[io]) */ for (i0 = ipos[0]; i0 < L_CODE; i0 += STEP) { ps0 = dn[i0]; move16 (); alp0 = L_mult(rr[i0][i0], _1_4); /*----------------------------------------------------------------* * i1 loop: 8 positions. * *----------------------------------------------------------------*/ sq = -1; move16 (); alp = 1; move16 (); ix = ipos[1]; move16 (); /*-------------------------------------------------------------------* * These index have low complexity address computation because * * they are, in fact, pointers with fixed increment. For example, * * "rr[i0][i2]" is a pointer initialized to "&rr[i0][ipos[2]]" * * and incremented by "STEP". * *-------------------------------------------------------------------*/ move16 (); /* account for ptr. init. (rr[i1]) */ move16 (); /* account for ptr. init. (dn[i1]) */ move16 (); /* account for ptr. init. (rr[io]) */ for (i1 = ipos[1]; i1 < L_CODE; i1 += STEP) { ps1 = add(ps0, dn[i1]); /* idx increment = STEP */ /* alp1 = alp0 + rr[i0][i1] + 1/2*rr[i1][i1]; */ alp1 = L_mac(alp0, rr[i1][i1], _1_4); /* idx incr = STEP */ alp1 = L_mac(alp1, rr[i0][i1], _1_2); /* idx incr = STEP */ sq1 = mult(ps1, ps1); alp_16 = round(alp1); s = L_msu(L_mult(alp, sq1), sq, alp_16); test (); if (s > 0) { sq = sq1; move16 (); alp = alp_16; move16 (); ix = i1; move16 (); } } /*----------------------------------------------------------------* * memorise codevector if this one is better than the last one. * *----------------------------------------------------------------*/ s = L_msu(L_mult(alpk, sq), psk, alp); test (); if (s > 0) { psk = sq; move16 (); alpk = alp; move16 (); codvec[0] = i0; move16 (); codvec[1] = ix; move16 (); } } } return; } /************************************************************************* * * FUNCTION: build_code() * * PURPOSE: Builds the codeword, the filtered codeword and index of the * codevector, based on the signs and positions of 2 pulses. * *************************************************************************/ static Word16 build_code( Word16 subNr, /* i : subframe number */ Word16 codvec[], /* i : position of pulses */ Word16 dn_sign[], /* i : sign of pulses */ Word16 cod[], /* o : innovative code vector */ Word16 h[], /* i : impulse response of weighted synthesis filter */ Word16 y[], /* o : filtered innovative code */ Word16 sign[] /* o : sign of 2 pulses */ ) { Word16 i, j, k, track, first, index, _sign[NB_PULSE], indx, rsign; Word16 *p0, *p1, *pt; Word32 s; static Word16 trackTable[4*5] = { 0, 1, 0, 1, -1, /* subframe 1; track to code; -1 do not code this position */ 0, -1, 1, 0, 1, /* subframe 2 */ 0, 1, 0, -1, 1, /* subframe 3 */ 0, 1, -1, 0, 1};/* subframe 4 */ pt = &trackTable[add(subNr, shl(subNr, 2))]; for (i = 0; i < L_CODE; i++) { cod[i] = 0; move16 (); } indx = 0; move16 (); rsign = 0; move16 (); for (k = 0; k < NB_PULSE; k++) { i = codvec[k]; /* read pulse position */ move16 (); j = dn_sign[i]; /* read sign */ move16 (); index = mult(i, 6554); /* index = pos/5 */ /* track = pos%5 */ track = sub(i, extract_l(L_shr(L_mult(index, 5), 1))); first = pt[track]; move16 (); test (); if (first == 0) { test (); if (k == 0) { track = 0; move16 (); } else { track = 1; move16 (); index = shl(index, 3); } } else { test (); if (k == 0) { track = 0; move16 (); index = add(index, 64); /* table bit is MSB */ } else { track = 1; move16 (); index = shl(index, 3); } } test (); if (j > 0) { cod[i] = 8191; move16 (); _sign[k] = 32767; move16 (); rsign = add(rsign, shl(1, track)); } else { cod[i] = -8192; move16 (); _sign[k] = (Word16) - 32768L; move16 (); } indx = add(indx, index); } *sign = rsign; move16 (); p0 = h - codvec[0]; move16 (); p1 = h - codvec[1]; move16 (); for (i = 0; i < L_CODE; i++) { s = 0; move32 (); s = L_mac(s, *p0++, _sign[0]); s = L_mac(s, *p1++, _sign[1]); y[i] = round(s); move16 (); } return indx; }