diff options
Diffstat (limited to 'media/libstagefright/codecs/amrnb/dec/src/preemph.cpp')
| -rw-r--r-- | media/libstagefright/codecs/amrnb/dec/src/preemph.cpp | 272 |
1 files changed, 272 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/amrnb/dec/src/preemph.cpp b/media/libstagefright/codecs/amrnb/dec/src/preemph.cpp new file mode 100644 index 0000000..9864325 --- /dev/null +++ b/media/libstagefright/codecs/amrnb/dec/src/preemph.cpp @@ -0,0 +1,272 @@ +/* ------------------------------------------------------------------ + * 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; +} + + + |