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Diffstat (limited to 'media/libstagefright/codecs/amrnb/dec/src/dec_lag6.cpp')
| -rw-r--r-- | media/libstagefright/codecs/amrnb/dec/src/dec_lag6.cpp | 337 |
1 files changed, 337 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/amrnb/dec/src/dec_lag6.cpp b/media/libstagefright/codecs/amrnb/dec/src/dec_lag6.cpp new file mode 100644 index 0000000..7dc7a8d --- /dev/null +++ b/media/libstagefright/codecs/amrnb/dec/src/dec_lag6.cpp @@ -0,0 +1,337 @@ +/* ------------------------------------------------------------------ + * 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/dec_lag6.c + Functions: Dec_lag6 + + Date: 01/31/2002 + +------------------------------------------------------------------------------ + REVISION HISTORY + + Description: + (1) Updated to accept new parameter, Flag *pOverflow. + (2) Placed file in the proper PV Software template. + + Description: + (1) Removed "count.h" and "basic_op.h" and replaced with individual include + files (add.h, sub.h, etc.) + + Description: + (1) Removed optimization -- mult(i, 3, pOverflow) is NOT the same as adding + i to itself 3 times. The reason is because the mult function does a + right shift by 15, which will obliterate smaller numbers. + + Description: Replaced "int" and/or "char" with OSCL defined types. + + Description: + + ------------------------------------------------------------------------------ + INPUT AND OUTPUT DEFINITIONS + + Inputs: + index -- Word16 -- received pitch index + pit_min -- Word16 -- minimum pitch lag + pit_max -- Word16 -- maximum pitch lag + i_subfr -- Word16 -- subframe flag + T0 -- Pointer to type Word16 -- integer part of pitch lag + + Outputs: + + T0 -- Pointer to type Word16 -- integer part of pitch lag + T0_frac -- Pointer to type Word16 -- fractional part of pitch lag + pOverflow -- Pointer to type Flag -- Flag set when overflow occurs + + Returns: + None. + + Global Variables Used: + None + + Local Variables Needed: + None + +------------------------------------------------------------------------------ + FUNCTION DESCRIPTION + + PURPOSE: Decoding of fractional pitch lag with 1/6 resolution. + Extract the integer and fraction parts of the pitch lag from + the received adaptive codebook index. + + See "Enc_lag6.c" for more details about the encoding procedure. + + The fractional lag in 1st and 3rd subframes is encoded with 9 bits + while that in 2nd and 4th subframes is relatively encoded with 6 bits. + Note that in relative encoding only 61 values are used. If the + decoder receives 61, 62, or 63 as the relative pitch index, it means + that a transmission error occurred. In this case, the pitch lag from + previous subframe (actually from previous frame) is used. + +------------------------------------------------------------------------------ + REQUIREMENTS + + + +------------------------------------------------------------------------------ + REFERENCES + + dec_lag6.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 + +------------------------------------------------------------------------------ + PSEUDO-CODE + + + +------------------------------------------------------------------------------ + RESOURCES USED + When the code is written for a specific target processor the + the resources used should be documented below. + + STACK USAGE: [stack count for this module] + [variable to represent + stack usage for each subroutine called] + + where: [stack usage variable] = stack usage for [subroutine + name] (see [filename].ext) + + DATA MEMORY USED: x words + + PROGRAM MEMORY USED: x words + + CLOCK CYCLES: [cycle count equation for this module] + [variable + used to represent cycle count for each subroutine + called] + + where: [cycle count variable] = cycle count for [subroutine + name] (see [filename].ext) + +------------------------------------------------------------------------------ +*/ + + +/*---------------------------------------------------------------------------- +; INCLUDES +----------------------------------------------------------------------------*/ +#include "dec_lag6.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 STORE/BUFFER/POINTER DEFINITIONS +; Variable declaration - defined here and used outside this module +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; EXTERNAL FUNCTION REFERENCES +; Declare functions defined elsewhere and referenced in this module +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES +; Declare variables used in this module but defined elsewhere +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; FUNCTION CODE +----------------------------------------------------------------------------*/ + +void Dec_lag6( + Word16 index, /* input : received pitch index */ + Word16 pit_min, /* input : minimum pitch lag */ + Word16 pit_max, /* input : maximum pitch lag */ + Word16 i_subfr, /* input : subframe flag */ + Word16 *T0, /* in/out: integer part of pitch lag */ + Word16 *T0_frac, /* output: fractional part of pitch lag */ + Flag *pOverflow /* o : Flag set when overflow occurs */ +) +{ + Word16 i; + Word16 T0_min; + Word16 T0_max; + Word16 k; + Word16 w; + + if (i_subfr == 0) /* if 1st or 3rd subframe */ + { + if (index < 463) + { + /* T0 = (index+5)/6 + 17 */ + i = index + 5; + i = + mult( + i, + 5462, + pOverflow); + + i = + add( + i, + 17, + pOverflow); + + *T0 = i; + + /* i = 3* (*T0) */ + + i = add(i, i, pOverflow); + i = add(i, *T0, pOverflow); + + /* *T0_frac = index - T0*6 + 105 */ + + i = + add( + i, + i, + pOverflow); + + i = + sub( + index, + i, + pOverflow); + + *T0_frac = + add( + i, + 105, + pOverflow); + } + else + { + *T0 = + sub( + index, + 368, + pOverflow); + + *T0_frac = 0; + } + } + else /* second or fourth subframe */ + { + /* find T0_min and T0_max for 2nd (or 4th) subframe */ + + T0_min = + sub( + *T0, + 5, + pOverflow); + + if (T0_min < pit_min) + { + T0_min = pit_min; + } + + T0_max = + add( + T0_min, + 9, + pOverflow); + + if (T0_max > pit_max) + { + T0_max = pit_max; + + T0_min = + sub( + T0_max, + 9, + pOverflow); + } + + /* i = (index+5)/6 - 1 */ + i = + add( + index, + 5, + pOverflow); + + i = + mult( + i, + 5462, + pOverflow); + + i = + sub( + i, + 1, + pOverflow); + + *T0 = + add( + i, + T0_min, + pOverflow); + + /* i = 3* (*T0) */ + + w = add(i, i, pOverflow); + i = add(i, w, pOverflow); + + i = + add( + i, + i, + pOverflow); + + k = + sub( + index, + 3, + pOverflow); + + *T0_frac = + sub( + k, + i, + pOverflow); + } +} |