| /* ------------------------------------------------------------------ |
| * 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/enc_lag6.c |
| Functions: |
| |
| Date: 02/05/2002 |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| Description: Updated template used to PV coding template. |
| Changed to accept the pOverflow flag for EPOC compatibility. |
| |
| Description: |
| (1) Removed optimization -- mult(i, 6, pOverflow) is NOT the same as adding |
| i to itself 6 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: |
| |
| ------------------------------------------------------------------------------ |
| MODULE DESCRIPTION |
| |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| #include "enc_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 VARIABLE DEFINITIONS |
| ; Variable declaration - defined here and used outside this module |
| ----------------------------------------------------------------------------*/ |
| |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: Enc_lag6 |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| T0 -- Word16 -- Pitch delay |
| T0_frac -- Word16 -- Fractional pitch delay |
| T0_min -- Word16 -- minimum of search range |
| delta_flag -- Word16 -- Flag for 1st (or 3rd) subframe |
| |
| Outputs: |
| pOverflow -- Pointer to Flag -- overflow indicator |
| |
| Returns: |
| Word16 -- Return index of encoding |
| |
| Global Variables Used: |
| None |
| |
| Local Variables Needed: |
| None |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| PURPOSE: Encoding of fractional pitch lag with 1/6 resolution. |
| |
| DESCRIPTION: |
| First and third subframes: |
| -------------------------- |
| The pitch range is divided as follows: |
| 17 3/6 to 94 3/6 resolution 1/6 |
| 95 to 143 resolution 1 |
| |
| The period is encoded with 9 bits. |
| For the range with fractions: |
| index = (T-17)*6 + frac - 3; |
| where T=[17..94] and frac=[-2,-1,0,1,2,3] |
| and for the integer only range |
| index = (T - 95) + 463; where T=[95..143] |
| |
| Second and fourth subframes: |
| ---------------------------- |
| For the 2nd and 4th subframes a resolution of 1/6 is always used, |
| and the search range is relative to the lag in previous subframe. |
| If t0 is the lag in the previous subframe then |
| t_min=t0-5 and t_max=t0+4 and the range is given by |
| (t_min-1) 3/6 to (t_max) 3/6 |
| |
| The period in the 2nd (and 4th) subframe is encoded with 6 bits: |
| index = (T-(t_min-1))*6 + frac - 3; |
| where T=[t_min-1..t_max] and frac=[-2,-1,0,1,2,3] |
| |
| Note that 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 and the pitch from previous subframe should be used. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| enc_lag6.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 Enc_lag6( /* o : Return index of encoding */ |
| Word16 T0, /* i : Pitch delay */ |
| Word16 T0_frac, /* i : Fractional pitch delay */ |
| Word16 T0_min, /* i : minimum of search range */ |
| Word16 delta_flag, /* i : Flag for 1st (or 3rd) subframe */ |
| Flag *pOverflow /* o : overflow indicator */ |
| ) |
| { |
| Word16 index; |
| Word16 i; |
| Word16 temp; |
| |
| if (delta_flag == 0) /* if 1st or 3rd subframe */ |
| { |
| /* encode pitch delay (with fraction) */ |
| if (T0 <= 94) |
| { |
| /* index = T0*6 - 105 + T0_frac */ |
| i = 6 * T0 - 105; |
| |
| index = add(i, T0_frac, pOverflow); |
| } |
| else |
| { |
| index = add(T0, 368, pOverflow); |
| } |
| |
| } |
| else |
| /* if second or fourth subframe */ |
| { |
| /* index = 6*(T0-T0_min) + 3 + T0_frac */ |
| temp = sub(T0, T0_min, pOverflow); |
| |
| i = add(temp, temp, pOverflow); |
| i = add(temp, i, pOverflow); |
| i = add(i, i, pOverflow); |
| |
| i = add(i, 3, pOverflow); |
| |
| index = add(i, T0_frac, pOverflow); |
| } |
| |
| return index; |
| } |
