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Diffstat (limited to 'opencore/codecs_v2/audio/gsm_amr/amr_nb/dec/src/a_refl.cpp')
| -rw-r--r-- | opencore/codecs_v2/audio/gsm_amr/amr_nb/dec/src/a_refl.cpp | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/opencore/codecs_v2/audio/gsm_amr/amr_nb/dec/src/a_refl.cpp b/opencore/codecs_v2/audio/gsm_amr/amr_nb/dec/src/a_refl.cpp new file mode 100644 index 0000000..674094f --- /dev/null +++ b/opencore/codecs_v2/audio/gsm_amr/amr_nb/dec/src/a_refl.cpp @@ -0,0 +1,283 @@ +/* ------------------------------------------------------------------ + * Copyright (C) 1998-2009 PacketVideo + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either + * express or implied. + * See the License for the specific language governing permissions + * and limitations under the License. + * ------------------------------------------------------------------- + */ +/**************************************************************************************** +Portions of this file are derived from the following 3GPP standard: + + 3GPP TS 26.073 + ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec + Available from http://www.3gpp.org + +(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC) +Permission to distribute, modify and use this file under the standard license +terms listed above has been obtained from the copyright holder. +****************************************************************************************/ +/* +------------------------------------------------------------------------------ + + + + Filename: a_refl.cpp + Functions: a_refl + +------------------------------------------------------------------------------ +*/ + + +/*---------------------------------------------------------------------------- +; INCLUDES +----------------------------------------------------------------------------*/ +#include "a_refl.h" +#include "typedef.h" +#include "cnst.h" +#include "basic_op.h" + +/*---------------------------------------------------------------------------- +; MACROS [optional] +; [Define module specific macros here] +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; DEFINES [optional] +; [Include all pre-processor statements here. Include conditional +; compile variables also.] +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; LOCAL FUNCTION DEFINITIONS +; [List function prototypes here] +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; LOCAL VARIABLE DEFINITIONS +; [Variable declaration - defined here and used outside this module] +----------------------------------------------------------------------------*/ + +/* +------------------------------------------------------------------------------ + FUNCTION NAME: AMREncode +------------------------------------------------------------------------------ + INPUT AND OUTPUT DEFINITIONS + + Inputs: + a[] = pointer to directform coefficients of type Word16 + refl[] = pointer to reflection coefficients of type Word16 + + Outputs: + pOverflow = 1 if overflow exists in the math operations else zero. + + Returns: + None + + Global Variables Used: + None + + Local Variables Needed: + None + +------------------------------------------------------------------------------ + FUNCTION DESCRIPTION + + File : a_refl.c + Purpose : Convert from direct form coefficients to + reflection coefficients + +------------------------------------------------------------------------------ + REQUIREMENTS + + None + +------------------------------------------------------------------------------ + REFERENCES + + [1] a_refl.c , 3GPP TS 26.101 version 4.1.0 Release 4, June 2001 + +------------------------------------------------------------------------------ + PSEUDO-CODE + + +void A_Refl( + Word16 a[], // i : Directform coefficients + Word16 refl[] // o : Reflection coefficients +) +{ + // local variables + Word16 i,j; + Word16 aState[M]; + Word16 bState[M]; + Word16 normShift; + Word16 normProd; + Word32 L_acc; + Word16 scale; + Word32 L_temp; + Word16 temp; + Word16 mult; + + // initialize states + for (i = 0; i < M; i++) + { + aState[i] = a[i]; + } + + // backward Levinson recursion + for (i = M-1; i >= 0; i--) + { + if (sub(abs_s(aState[i]), 4096) >= 0) + { + goto ExitRefl; + } + + refl[i] = shl(aState[i], 3); + + L_temp = L_mult(refl[i], refl[i]); + L_acc = L_sub(MAX_32, L_temp); + + normShift = norm_l(L_acc); + scale = sub(15, normShift); + + L_acc = L_shl(L_acc, normShift); + normProd = pv_round(L_acc); + + mult = div_s(16384, normProd); + + for (j = 0; j < i; j++) + { + L_acc = L_deposit_h(aState[j]); + L_acc = L_msu(L_acc, refl[i], aState[i-j-1]); + + temp = pv_round(L_acc); + L_temp = L_mult(mult, temp); + L_temp = L_shr_r(L_temp, scale); + + if (L_sub(L_abs(L_temp), 32767) > 0) + { + goto ExitRefl; + } + + bState[j] = extract_l(L_temp); + } + + for (j = 0; j < i; j++) + { + aState[j] = bState[j]; + } + } + return; + +ExitRefl: + for (i = 0; i < M; i++) + { + refl[i] = 0; + } +} + +------------------------------------------------------------------------------ + CAUTION [optional] + [State any special notes, constraints or cautions for users of this function] + +------------------------------------------------------------------------------ +*/ + +void A_Refl( + Word16 a[], /* i : Directform coefficients */ + Word16 refl[], /* o : Reflection coefficients */ + Flag *pOverflow +) +{ + /* local variables */ + Word16 i; + Word16 j; + Word16 aState[M]; + Word16 bState[M]; + Word16 normShift; + Word16 normProd; + Word32 L_acc; + Word16 scale; + Word32 L_temp; + Word16 temp; + Word16 mult; + + /* initialize states */ + for (i = 0; i < M; i++) + { + aState[i] = a[i]; + } + + /* backward Levinson recursion */ + for (i = M - 1; i >= 0; i--) + { + if (abs_s(aState[i]) >= 4096) + { + for (i = 0; i < M; i++) + { + refl[i] = 0; + } + break; + } + + refl[i] = shl(aState[i], 3, pOverflow); + + L_temp = L_mult(refl[i], refl[i], pOverflow); + L_acc = L_sub(MAX_32, L_temp, pOverflow); + + normShift = norm_l(L_acc); + scale = 15 - normShift; + + L_acc = L_shl(L_acc, normShift, pOverflow); + normProd = pv_round(L_acc, pOverflow); + + mult = div_s(16384, normProd); + + for (j = 0; j < i; j++) + { + L_acc = ((Word32)aState[j] << 16); + L_acc = L_msu(L_acc, refl[i], aState[i-j-1], pOverflow); + + temp = pv_round(L_acc, pOverflow); + L_temp = L_mult(mult, temp, pOverflow); + L_temp = L_shr_r(L_temp, scale, pOverflow); + + + Word32 L_tmp_abs = L_temp - (L_temp < 0); + L_tmp_abs = L_tmp_abs ^(L_tmp_abs >> 31); + + if (L_tmp_abs > 32767) + { + for (i = 0; i < M; i++) + { + refl[i] = 0; + } + break; + } + + bState[j] = (Word16)(L_temp); + } + + for (j = 0; j < i; j++) + { + aState[j] = bState[j]; + } + } + return; +} + + + + + + + |