| /* ------------------------------------------------------------------ |
| * 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. |
| ****************************************************************************************/ |
| /* |
| Pathname: ./audio/gsm-amr/c/src/lsp_lsf.c |
| Functions: Lsp_lsf |
| Lsf_lsp |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| Description: Updated template used to PV coding template. |
| |
| Description: Deleted variables listed in the Local Stores Needed/Modified |
| section. |
| |
| Description: Synchronized file with UMTS version 3.2.0. Updated coding |
| template and removed unnecessary include files. |
| |
| Description: Replaced basic_op.h with the header file of the math functions |
| used in the file. |
| |
| Description: Changed to accept the pOverflow flag for EPOC compatibility. |
| |
| Description: Placed table declarations in a .c file, rather than an included |
| .tab. The tables are now referenced via an extern in this file. |
| |
| Description: For Lsp_lsf() |
| 1. Eliminated unused include file typedef.h. |
| 2. Replaced array addressing by pointers |
| |
| Description: Replaced "int" and/or "char" with defined types. |
| Added proper casting (Word32) to some left shifting operations |
| |
| Description: Changed round function name to pv_round to avoid conflict with |
| round function in C standard library. |
| |
| Description: Added #ifdef __cplusplus around extern'ed table. |
| |
| Who: Date: |
| Description: |
| |
| ------------------------------------------------------------------------------ |
| MODULE DESCRIPTION |
| |
| This file contains the functions that convert line spectral pairs (LSP) to |
| line spectral frequencies (LSF) and vice-versa. |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| #include "lsp_lsf.h" |
| #include "basicop_malloc.h" |
| #include "basic_op.h" |
| |
| /*--------------------------------------------------------------------------*/ |
| #ifdef __cplusplus |
| extern "C" |
| { |
| #endif |
| |
| /*---------------------------------------------------------------------------- |
| ; MACROS |
| ; Define module specific macros here |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; DEFINES |
| ; Include all pre-processor statements here. Include conditional |
| ; compile variables also. |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL FUNCTION DEFINITIONS |
| ; Function Prototype declaration |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL VARIABLE DEFINITIONS |
| ; Variable declaration - defined here and used outside this module |
| ----------------------------------------------------------------------------*/ |
| |
| extern const Word16 table[]; |
| extern const Word16 slope[]; |
| |
| |
| /*--------------------------------------------------------------------------*/ |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: Lsf_lsp |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| lsf = buffer containing normalized line spectral frequencies; valid |
| range is between 0 and 0.5 (Word16) |
| lsp = buffer containing line spectral pairs; valid range is between |
| -1 and 1 (Word16) |
| m = LPC order (Word16) |
| |
| Outputs: |
| lsp contains the newly calculated line spectral pairs |
| |
| Returns: |
| None |
| |
| Global Variables Used: |
| table = cosine table |
| |
| Local Variables Needed: |
| None |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| This function performs the LSF to LSP transformation using the equation: |
| |
| lsf[i] = arccos(lsp[i])/(2*pi) |
| |
| The transformation from lsp[i] to lsf[i] is approximated by a look-up table |
| and interpolation. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| lsp_lsf.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| void Lsf_lsp ( |
| Word16 lsf[], // (i) : lsf[m] normalized (range: 0.0<=val<=0.5) |
| Word16 lsp[], // (o) : lsp[m] (range: -1<=val<1) |
| Word16 m // (i) : LPC order |
| ) |
| { |
| Word16 i, ind, offset; |
| Word32 L_tmp; |
| |
| for (i = 0; i < m; i++) |
| { |
| ind = shr (lsf[i], 8); // ind = b8-b15 of lsf[i] |
| offset = lsf[i] & 0x00ff; // offset = b0-b7 of lsf[i] |
| |
| // lsp[i] = table[ind]+ ((table[ind+1]-table[ind])*offset) / 256 |
| |
| L_tmp = L_mult (sub (table[ind + 1], table[ind]), offset); |
| lsp[i] = add (table[ind], extract_l (L_shr (L_tmp, 9))); |
| |
| } |
| return; |
| } |
| |
| ------------------------------------------------------------------------------ |
| RESOURCES USED [optional] |
| |
| When the code is written for a specific target processor the |
| the resources used should be documented below. |
| |
| HEAP MEMORY USED: x bytes |
| |
| STACK MEMORY USED: x bytes |
| |
| CLOCK CYCLES: (cycle count equation for this function) + (variable |
| used to represent cycle count for each subroutine |
| called) |
| where: (cycle count variable) = cycle count for [subroutine |
| name] |
| |
| ------------------------------------------------------------------------------ |
| CAUTION [optional] |
| [State any special notes, constraints or cautions for users of this function] |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| void Lsf_lsp( |
| Word16 lsf[], /* (i) : lsf[m] normalized (range: 0.0<=val<=0.5) */ |
| Word16 lsp[], /* (o) : lsp[m] (range: -1<=val<1) */ |
| Word16 m, /* (i) : LPC order */ |
| Flag *pOverflow /* (o) : Flag set when overflow occurs */ |
| ) |
| { |
| Word16 i, ind, offset; |
| Word32 L_tmp; |
| |
| for (i = 0; i < m; i++) |
| { |
| ind = lsf[i] >> 8; /* ind = b8-b15 of lsf[i] */ |
| offset = lsf[i] & 0x00ff; /* offset = b0-b7 of lsf[i] */ |
| |
| /* lsp[i] = table[ind]+ ((table[ind+1]-table[ind])*offset) / 256 */ |
| |
| L_tmp = ((Word32)(table[ind + 1] - table[ind]) * offset) >> 8; |
| lsp[i] = add(table[ind], (Word16) L_tmp, pOverflow); |
| |
| } |
| |
| return; |
| } |
| |
| /****************************************************************************/ |
| |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: Lsp_lsf |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| lsp = buffer containing line spectral pairs; valid range is between |
| -1 and 1 (Word16) |
| lsf = buffer containing normalized line spectral frequencies; valid |
| range is between 0 and 0.5 (Word16) |
| m = LPC order (Word16) |
| |
| Outputs: |
| lsf contains the newly calculated normalized line spectral frequencies |
| |
| Returns: |
| None |
| |
| Global Variables Used: |
| table = cosine table |
| slope = table to used to calculate inverse cosine |
| |
| Local Variables Needed: |
| None |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| This function performs the LSP to LSF transformation using the equation: |
| |
| lsp[i] = cos(2*pi*lsf[i]) |
| |
| The transformation from lsf[i] to lsp[i] is approximated by a look-up table |
| and interpolation. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| lsp_lsf.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| void Lsp_lsf ( |
| Word16 lsp[], // (i) : lsp[m] (range: -1<=val<1) |
| Word16 lsf[], // (o) : lsf[m] normalized (range: 0.0<=val<=0.5) |
| Word16 m // (i) : LPC order |
| ) |
| { |
| Word16 i, ind; |
| Word32 L_tmp; |
| |
| ind = 63; // begin at end of table -1 |
| |
| for (i = m - 1; i >= 0; i--) |
| { |
| // find value in table that is just greater than lsp[i] |
| |
| while (sub (table[ind], lsp[i]) < 0) |
| { |
| ind--; |
| |
| } |
| |
| // acos(lsp[i])= ind*256 + ( ( lsp[i]-table[ind] ) * |
| slope[ind] )/4096 |
| |
| L_tmp = L_mult (sub (lsp[i], table[ind]), slope[ind]); |
| //(lsp[i]-table[ind])*slope[ind])>>12 |
| lsf[i] = pv_round (L_shl (L_tmp, 3)); |
| lsf[i] = add (lsf[i], shl (ind, 8)); |
| } |
| return; |
| } |
| |
| ------------------------------------------------------------------------------ |
| RESOURCES USED [optional] |
| |
| When the code is written for a specific target processor the |
| the resources used should be documented below. |
| |
| HEAP MEMORY USED: x bytes |
| |
| STACK MEMORY USED: x bytes |
| |
| CLOCK CYCLES: (cycle count equation for this function) + (variable |
| used to represent cycle count for each subroutine |
| called) |
| where: (cycle count variable) = cycle count for [subroutine |
| name] |
| |
| ------------------------------------------------------------------------------ |
| CAUTION [optional] |
| [State any special notes, constraints or cautions for users of this function] |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| void Lsp_lsf( |
| Word16 lsp[], /* (i) : lsp[m] (range: -1<=val<1) */ |
| Word16 lsf[], /* (o) : lsf[m] normalized (range: 0.0<=val<=0.5) */ |
| Word16 m, /* (i) : LPC order */ |
| Flag *pOverflow /* (o) : Flag set when overflow occurs */ |
| ) |
| { |
| Word16 i; |
| Word16 ind; |
| Word16 temp; |
| Word32 L_tmp; |
| Word16 *p_lsp = &lsp[m-1]; |
| Word16 *p_lsf = &lsf[m-1]; |
| OSCL_UNUSED_ARG(pOverflow); |
| |
| ind = 63; /* begin at end of table -1 */ |
| |
| for (i = m - 1; i >= 0; i--) |
| { |
| /* find value in table that is just greater than lsp[i] */ |
| temp = *(p_lsp--); |
| while (table[ind] < temp) |
| { |
| ind--; |
| } |
| |
| /* acos(lsp[i])= ind*256 + ( ( lsp[i]-table[ind] ) * |
| slope[ind] )/4096 */ |
| |
| L_tmp = (Word32)(temp - table[ind]) * slope[ind]; |
| |
| /*(lsp[i]-table[ind])*slope[ind])>>12*/ |
| L_tmp = (L_tmp + 0x00000800) >> 12; |
| |
| *(p_lsf--) = (Word16)(L_tmp) + (ind << 8); |
| } |
| |
| return; |
| } |
