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Diffstat (limited to 'media/libstagefright/codecs/amrnb/enc/src/enc_lag6.cpp')
| -rw-r--r-- | media/libstagefright/codecs/amrnb/enc/src/enc_lag6.cpp | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/amrnb/enc/src/enc_lag6.cpp b/media/libstagefright/codecs/amrnb/enc/src/enc_lag6.cpp new file mode 100644 index 0000000..2c7863e --- /dev/null +++ b/media/libstagefright/codecs/amrnb/enc/src/enc_lag6.cpp @@ -0,0 +1,230 @@ +/* ------------------------------------------------------------------ + * 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; +} |