| /* ------------------------------------------------------------------ |
| * 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/preemph.c |
| Functions: |
| |
| Date: 02/04/2002 |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| Description: Removed the functions preemphasis_init and preemphasis_exit. |
| The preemphasis related structure is no longer dynamically allocated. |
| Placed file in the appropriate PV Software Template format. |
| |
| Description: Changed to accept the pOverflow flag for EPOC compatibility. |
| |
| Description: Replaced OSCL mem type functions and eliminated include |
| files that now are chosen by OSCL definitions |
| |
| Description: Replaced "int" and/or "char" with OSCL defined types. |
| |
| Description: |
| |
| ------------------------------------------------------------------------------ |
| MODULE DESCRIPTION |
| |
| Purpose : Preemphasis filtering |
| Description : Filtering through 1 - g z^-1 |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| #include "preemph.h" |
| #include "typedef.h" |
| #include "basic_op.h" |
| |
| /*---------------------------------------------------------------------------- |
| ; 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 |
| ----------------------------------------------------------------------------*/ |
| |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: preemphasis_reset |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| st -- double pointer to preemphasisState |
| |
| Outputs: |
| st -- double ponter to preemphasisState |
| |
| Returns: |
| -1 if an error occurs |
| 0 if OK |
| |
| Global Variables Used: |
| None |
| |
| Local Variables Needed: |
| None |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| Initializes state memory to zero |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| preemph.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| |
| ------------------------------------------------------------------------------ |
| 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] |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| Word16 preemphasis_reset(preemphasisState *state) |
| { |
| if (state == (preemphasisState *) NULL) |
| { |
| /* fprintf(stderr, "preemphasis_reset: invalid parameter\n"); */ |
| return -1; |
| } |
| |
| state->mem_pre = 0; |
| |
| return 0; |
| } |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: preemphasis |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| st -- Pointer to preemphasisState -- preemphasis filter state |
| signal -- array of type Word16 -- input signal overwritten by the output |
| g -- Word16 -- preemphasis coefficient |
| L -- Word16 -- size of filtering |
| |
| Outputs: |
| st -- Pointer to preemphasisState -- preemphasis filter state |
| signal -- array of type Word16 -- input signal overwritten by the output |
| pOverflow -- pointer to type Flag -- overflow indicator |
| Returns: |
| None |
| |
| Global Variables Used: |
| None |
| |
| Local Variables Needed: |
| None |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| Filtering through 1 - g z^-1 |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| preemph.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| |
| ------------------------------------------------------------------------------ |
| 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 preemphasis( |
| preemphasisState *st, /* (i/o) : preemphasis filter state */ |
| Word16 *signal, /* (i/o) : input signal overwritten by the output */ |
| Word16 g, /* (i) : preemphasis coefficient */ |
| Word16 L, /* (i) : size of filtering */ |
| Flag *pOverflow /* (o) : overflow indicator */ |
| ) |
| { |
| Word16 *p1; |
| Word16 *p2; |
| Word16 temp; |
| Word16 temp2; |
| Word16 i; |
| |
| p1 = signal + L - 1; |
| p2 = p1 - 1; |
| temp = *p1; |
| |
| for (i = 0; i <= L - 2; i++) |
| { |
| temp2 = mult(g, *(p2--), pOverflow); |
| *p1 = sub(*p1, temp2, pOverflow); |
| |
| p1--; |
| } |
| |
| temp2 = mult(g, st->mem_pre, pOverflow); |
| |
| *p1 = sub(*p1, temp2, pOverflow); |
| |
| st->mem_pre = temp; |
| |
| return; |
| } |
| |
| |
| |