FreeCalypso > hg > gsm-codec-lib
view libtwamr/cbsearch.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 | 4614f1a97e1a |
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 : cbsearch.c * Purpose : Inovative codebook search (find index and gain) * ***************************************************************************** */ /* ***************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ***************************************************************************** */ #include "namespace.h" #include "cbsearch.h" /* ***************************************************************************** * INCLUDE FILES ***************************************************************************** */ #include "tw_amr.h" #include "typedef.h" #include "c2_9pf.h" #include "c2_11pf.h" #include "c3_14pf.h" #include "c4_17pf.h" #include "c8_31pf.h" #include "c1035pf.h" #include "basic_op.h" #include "no_count.h" #include "cnst.h" /* ***************************************************************************** * PUBLIC PROGRAM CODE ***************************************************************************** */ int cbsearch(Word16 x[], /* i : target vector, Q0 */ Word16 h[], /* i : impulse response of weighted synthesis */ /* filter h[-L_subfr..-1] must be set to */ /* zero. Q12 */ Word16 T0, /* i : Pitch lag */ Word16 pitch_sharp, /* i : Last quantized pitch gain, Q14 */ Word16 gain_pit, /* i : Pitch gain, Q14 */ Word16 res2[], /* i : Long term prediction residual, Q0 */ Word16 code[], /* o : Innovative codebook, Q13 */ Word16 y[], /* o : filtered fixed codebook excitation, Q12 */ Word16 **anap, /* o : Signs of the pulses */ enum Mode mode,/* i : coder mode */ Word16 subNr) /* i : subframe number */ { Word16 index; Word16 i, temp, pit_sharpTmp; /* For MR74, the pre and post CB pitch sharpening is included in the * codebook search routine, while for MR122 is it not. */ test (); test (); if ((sub (mode, MR475) == 0) || (sub (mode, MR515) == 0)) { /* MR475, MR515 */ move16 (); *(*anap)++ = code_2i40_9bits(subNr, x, h, T0, pitch_sharp, code, y, &index); *(*anap)++ = index; /* sign index */ move16 (); } else if (sub (mode, MR59) == 0) { /* MR59 */ test (); move16 (); *(*anap)++ = code_2i40_11bits(x, h, T0, pitch_sharp, code, y, &index); *(*anap)++ = index; /* sign index */ move16 (); } else if (sub (mode, MR67) == 0) { /* MR67 */ test (); test (); move16 (); *(*anap)++ = code_3i40_14bits(x, h, T0, pitch_sharp, code, y, &index); *(*anap)++ = index; /* sign index */ move16 (); } else if (sub (mode, MR74) == 0 || sub (mode, MR795) == 0) { /* MR74, MR795 */ test (); test (); test (); move16 (); *(*anap)++ = code_4i40_17bits(x, h, T0, pitch_sharp, code, y, &index); *(*anap)++ = index; /* sign index */ move16 (); } else if (sub (mode, MR102) == 0) { /* MR102 */ test (); test (); test (); /*-------------------------------------------------------------* * - include pitch contribution into impulse resp. h1[] * *-------------------------------------------------------------*/ /* pit_sharpTmp = pit_sharp; */ /* if (pit_sharpTmp > 1.0) pit_sharpTmp = 1.0; */ pit_sharpTmp = shl (pitch_sharp, 1); for (i = T0; i < L_SUBFR; i++) { temp = mult(h[i - T0], pit_sharpTmp); h[i] = add(h[i], temp); move16 (); } /*--------------------------------------------------------------* * - Innovative codebook search (find index and gain) * *--------------------------------------------------------------*/ code_8i40_31bits (x, res2, h, code, y, *anap); *anap += 7; add(0,0); /*-------------------------------------------------------* * - Add the pitch contribution to code[]. * *-------------------------------------------------------*/ for (i = T0; i < L_SUBFR; i++) { temp = mult (code[i - T0], pit_sharpTmp); code[i] = add (code[i], temp); move16 (); } } else { /* MR122 */ /*-------------------------------------------------------------* * - include pitch contribution into impulse resp. h1[] * *-------------------------------------------------------------*/ test (); test (); test (); /* pit_sharpTmp = gain_pit; */ /* if (pit_sharpTmp > 1.0) pit_sharpTmp = 1.0; */ pit_sharpTmp = shl (gain_pit, 1); for (i = T0; i < L_SUBFR; i++) { temp = mult(h[i - T0], pit_sharpTmp); h[i] = add(h[i], temp); move16 (); } /*--------------------------------------------------------------* * - Innovative codebook search (find index and gain) * *--------------------------------------------------------------*/ code_10i40_35bits (x, res2, h, code, y, *anap); *anap += 10; add(0,0); /*-------------------------------------------------------* * - Add the pitch contribution to code[]. * *-------------------------------------------------------*/ for (i = T0; i < L_SUBFR; i++) { temp = mult (code[i - T0], pit_sharpTmp); code[i] = add (code[i], temp); move16 (); } } return 0; }