FreeCalypso > hg > gsm-codec-lib
view libtwamr/c1035pf.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 | 6fd6c5fc1aa4 |
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 : c1035pf.c * Purpose : Searches a 35 bit algebraic codebook containing * : 10 pulses in a frame of 40 samples. * ******************************************************************************** */ /* ******************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ******************************************************************************** */ #include "namespace.h" #include "c1035pf.h" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "typedef.h" #include "basic_op.h" #include "no_count.h" #include "cnst.h" #include "inv_sqrt.h" #include "set_sign.h" #include "cor_h.h" #include "s10_8pf.h" #include "graytab.h" /* ******************************************************************************** * LOCAL VARIABLES AND TABLES ******************************************************************************** */ #define NB_PULSE 10 /* ******************************************************************************** * LOCAL PROGRAM CODE ******************************************************************************** */ static void q_p ( Word16 *ind, /* Pulse position */ Word16 n /* Pulse number */ ) { Word16 tmp; tmp = *ind; move16 (); test (); if (sub (n, 5) < 0) { *ind = (tmp & 0x8) | gray[tmp & 0x7]; logic16 (); logic16 (); logic16 (); move16 (); } else { *ind = gray[tmp & 0x7]; logic16 (); move16 (); } } /************************************************************************* * * FUNCTION: build_code() * * PURPOSE: Builds the codeword, the filtered codeword and index of the * codevector, based on the signs and positions of 10 pulses. * *************************************************************************/ static void build_code ( Word16 codvec[], /* (i) : position of pulses */ Word16 sign[], /* (i) : sign of d[n] */ Word16 cod[], /* (o) : innovative code vector */ Word16 h[], /* (i) : impulse response of weighted synthesis filter*/ Word16 y[], /* (o) : filtered innovative code */ Word16 indx[] /* (o) : index of 10 pulses (sign+position) */ ) { Word16 i, j, k, track, index, _sign[NB_PULSE]; Word16 *p0, *p1, *p2, *p3, *p4, *p5, *p6, *p7, *p8, *p9; Word32 s; for (i = 0; i < L_CODE; i++) { cod[i] = 0; move16 (); } for (i = 0; i < NB_TRACK; i++) { indx[i] = -1; move16 (); } for (k = 0; k < NB_PULSE; k++) { /* read pulse position */ i = codvec[k]; move16 (); /* read sign */ j = sign[i]; move16 (); index = mult (i, 6554); /* index = pos/5 */ /* track = pos%5 */ track = sub (i, extract_l (L_shr (L_mult (index, 5), 1))); test (); if (j > 0) { cod[i] = add (cod[i], 4096); move16 (); _sign[k] = 8192; move16 (); } else { cod[i] = sub (cod[i], 4096); move16 (); _sign[k] = -8192; move16 (); index = add (index, 8); } test (); move16 (); if (indx[track] < 0) { indx[track] = index; move16 (); } else { test (); logic16 (); logic16 (); if (((index ^ indx[track]) & 8) == 0) { /* sign of 1st pulse == sign of 2nd pulse */ test (); if (sub (indx[track], index) <= 0) { indx[track + 5] = index; move16 (); } else { indx[track + 5] = indx[track]; move16 (); indx[track] = index; move16 (); } } else { /* sign of 1st pulse != sign of 2nd pulse */ test (); logic16 (); logic16 (); if (sub ((indx[track] & 7), (index & 7)) <= 0) { indx[track + 5] = indx[track]; move16 (); indx[track] = index; move16 (); } else { indx[track + 5] = index; move16 (); } } } } p0 = h - codvec[0]; move16 (); p1 = h - codvec[1]; move16 (); p2 = h - codvec[2]; move16 (); p3 = h - codvec[3]; move16 (); p4 = h - codvec[4]; move16 (); p5 = h - codvec[5]; move16 (); p6 = h - codvec[6]; move16 (); p7 = h - codvec[7]; move16 (); p8 = h - codvec[8]; move16 (); p9 = h - codvec[9]; 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]); s = L_mac (s, *p2++, _sign[2]); s = L_mac (s, *p3++, _sign[3]); s = L_mac (s, *p4++, _sign[4]); s = L_mac (s, *p5++, _sign[5]); s = L_mac (s, *p6++, _sign[6]); s = L_mac (s, *p7++, _sign[7]); s = L_mac (s, *p8++, _sign[8]); s = L_mac (s, *p9++, _sign[9]); y[i] = round (s); move16 (); } } /* ******************************************************************************** * PUBLIC PROGRAM CODE ******************************************************************************** */ /************************************************************************* * * FUNCTION: code_10i40_35bits() * * PURPOSE: Searches a 35 bit algebraic codebook containing 10 pulses * in a frame of 40 samples. * * DESCRIPTION: * The code contains 10 nonzero pulses: i0...i9. * All pulses can have two possible amplitudes: +1 or -1. * The 40 positions in a subframe are divided into 5 tracks of * interleaved positions. Each track contains two pulses. * The pulses can have the following possible positions: * * i0, i5 : 0, 5, 10, 15, 20, 25, 30, 35. * i1, i6 : 1, 6, 11, 16, 21, 26, 31, 36. * i2, i7 : 2, 7, 12, 17, 22, 27, 32, 37. * i3, i8 : 3, 8, 13, 18, 23, 28, 33, 38. * i4, i9 : 4, 9, 14, 19, 24, 29, 34, 39. * * Each pair of pulses require 1 bit for their signs and 6 bits for their * positions (3 bits + 3 bits). This results in a 35 bit codebook. * The function determines the optimal pulse signs and positions, builds * the codevector, and computes the filtered codevector. * *************************************************************************/ void code_10i40_35bits ( Word16 x[], /* (i) : target vector */ Word16 cn[], /* (i) : residual after long term prediction */ Word16 h[], /* (i) : impulse response of weighted synthesis filter h[-L_subfr..-1] must be set to zero */ Word16 cod[], /* (o) : algebraic (fixed) codebook excitation */ Word16 y[], /* (o) : filtered fixed codebook excitation */ Word16 indx[] /* (o) : index of 10 pulses (sign + position) */ ) { Word16 ipos[NB_PULSE], pos_max[NB_TRACK], codvec[NB_PULSE]; Word16 dn[L_CODE], sign[L_CODE]; Word16 rr[L_CODE][L_CODE], i; cor_h_x (h, x, dn, 2); set_sign12k2 (dn, cn, sign, pos_max, NB_TRACK, ipos, STEP); cor_h (h, sign, rr); search_10and8i40 (NB_PULSE, STEP, NB_TRACK, dn, rr, ipos, pos_max, codvec); build_code (codvec, sign, cod, h, y, indx); for (i = 0; i < 10; i++) { q_p (&indx[i], i); } return; }