| /* ------------------------------------------------------------------ |
| * 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); |
| } |
| } |
