diff options
Diffstat (limited to 'media/libstagefright/codecs/amrnb/enc/src/enc_lag3.cpp')
| -rw-r--r-- | media/libstagefright/codecs/amrnb/enc/src/enc_lag3.cpp | 356 |
1 files changed, 356 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/amrnb/enc/src/enc_lag3.cpp b/media/libstagefright/codecs/amrnb/enc/src/enc_lag3.cpp new file mode 100644 index 0000000..a1fc008 --- /dev/null +++ b/media/libstagefright/codecs/amrnb/enc/src/enc_lag3.cpp @@ -0,0 +1,356 @@ +/* ------------------------------------------------------------------ + * 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_lag3.c + Functions: + + Date: 01/28/2002 + +------------------------------------------------------------------------------ + REVISION HISTORY + + Description: Replaced "int" and/or "char" with OSCL defined types. + + Description: + +------------------------------------------------------------------------------ +*/ + +/*---------------------------------------------------------------------------- +; INCLUDES +----------------------------------------------------------------------------*/ +#include "enc_lag3.h" +#include "typedef.h" +#include "basic_op.h" +#include "cnst.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_lag3 +------------------------------------------------------------------------------ + INPUT AND OUTPUT DEFINITIONS + + Inputs: + T0 = Pitch delay of type Word16 + T0_frac = Fractional pitch delay of type Word16 + T0_prev = Integer pitch delay of last subframe of type Word16 + T0_min = minimum of search range of type Word16 + T0_max = maximum of search range of type Word16 + delta_flag = Flag for 1st (or 3rd) subframe of type Word16 + flag4 = Flag for encoding with 4 bits of type Word16 + pOverflow = pointer indicating overflow of type Flag + + Outputs: + pOverflow = 1 if there is an overflow else it is zero. + + Returns: + None + + Global Variables Used: + None + + Local Variables Needed: + None + +------------------------------------------------------------------------------ + FUNCTION DESCRIPTION + + This function implements the encoding of fractional pitch lag with + 1/3 resolution. + + * FUNCTION: Enc_lag3 + * + * PURPOSE: Encoding of fractional pitch lag with 1/3 resolution. + * + * DESCRIPTION: + * First and third subframes: + * -------------------------- + * The pitch range is divided as follows: + * 19 1/3 to 84 2/3 resolution 1/3 + * 85 to 143 resolution 1 + * + * The period is encoded with 8 bits. + * For the range with fractions: + * index = (T-19)*3 + frac - 1; + * where T=[19..85] and frac=[-1,0,1] + * and for the integer only range + * index = (T - 85) + 197; where T=[86..143] + * + * Second and fourth subframes: + * ---------------------------- + * For the 2nd and 4th subframes a resolution of 1/3 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 - 2/3 to t_max + 2/3 + * + * The period in the 2nd (and 4th) subframe is encoded with 5 bits: + * index = (T-(t_min-1))*3 + frac - 1; + * where T=[t_min-1..t_max+1] + +------------------------------------------------------------------------------ + REQUIREMENTS + + None + +------------------------------------------------------------------------------ + REFERENCES + + enc_lag3.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 + +------------------------------------------------------------------------------ + PSEUDO-CODE + + Word16 index, i, tmp_ind, uplag; + Word16 tmp_lag; + + if (delta_flag == 0) + { // if 1st or 3rd subframe + + // encode pitch delay (with fraction) + + if (sub (T0, 85) <= 0) + { + // index = T0*3 - 58 + T0_frac + i = add (add (T0, T0), T0); + index = add (sub (i, 58), T0_frac); + } + else + { + index = add (T0, 112); + } + } + else + { // if second or fourth subframe + if (flag4 == 0) { + + // 'normal' encoding: either with 5 or 6 bit resolution + + // index = 3*(T0 - T0_min) + 2 + T0_frac + i = sub (T0, T0_min); + i = add (add (i, i), i); + index = add (add (i, 2), T0_frac); + } + else { + + // encoding with 4 bit resolution + + tmp_lag = T0_prev; + + if ( sub( sub(tmp_lag, T0_min), 5) > 0) + tmp_lag = add (T0_min, 5); + if ( sub( sub(T0_max, tmp_lag), 4) > 0) + tmp_lag = sub (T0_max, 4); + + uplag = add (add (add (T0, T0), T0), T0_frac); + + i = sub (tmp_lag, 2); + tmp_ind = add (add (i, i), i); + + if (sub (tmp_ind, uplag) >= 0) { + index = add (sub (T0, tmp_lag), 5); + } + else { + + i = add (tmp_lag, 1); + i = add (add (i, i), i); + + if (sub (i, uplag) > 0) { + + index = add ( sub (uplag, tmp_ind), 3); + } + else { + + index = add (sub (T0, tmp_lag), 11); + } + } + + } // end if (encoding with 4 bit resolution) + } // end if (second of fourth subframe) + + return index; +} + +------------------------------------------------------------------------------ + 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_lag3( /* o : Return index of encoding */ + Word16 T0, /* i : Pitch delay */ + Word16 T0_frac, /* i : Fractional pitch delay */ + Word16 T0_prev, /* i : Integer pitch delay of last subframe */ + Word16 T0_min, /* i : minimum of search range */ + Word16 T0_max, /* i : maximum of search range */ + Word16 delta_flag, /* i : Flag for 1st (or 3rd) subframe */ + Word16 flag4, /* i : Flag for encoding with 4 bits */ + Flag *pOverflow +) +{ + Word16 index, i, tmp_ind, uplag; + Word16 tmp_lag; + Word16 temp1; + Word16 temp2; + + + + if (delta_flag == 0) + { /* if 1st or 3rd subframe */ + + /* encode pitch delay (with fraction) */ + temp1 = sub(T0, 85, pOverflow); + if (temp1 <= 0) + { + /* index = T0*3 - 58 + T0_frac */ + temp2 = add(T0, T0, pOverflow); + i = add(temp2, T0, pOverflow); + temp2 = sub(i, 58, pOverflow); + index = add(temp2, T0_frac, pOverflow); + } + else + { + index = add(T0, 112, pOverflow); + } + } + else + { /* if second or fourth subframe */ + if (flag4 == 0) + { + + /* 'normal' encoding: either with 5 or 6 bit resolution */ + + /* index = 3*(T0 - T0_min) + 2 + T0_frac */ + i = sub(T0, T0_min, pOverflow); + temp2 = add(i, i, pOverflow); + i = add(temp2, i, pOverflow); + temp2 = add(i, 2, pOverflow); + index = add(temp2, T0_frac, pOverflow); + } + else + { + + /* encoding with 4 bit resolution */ + + tmp_lag = T0_prev; + temp1 = sub(tmp_lag, T0_min, pOverflow); + temp2 = sub(temp1, 5, pOverflow); + if (temp2 > 0) + tmp_lag = add(T0_min, 5, pOverflow); + temp1 = sub(T0_max, tmp_lag, pOverflow); + temp2 = sub(temp1, 4, pOverflow); + if (temp2 > 0) + tmp_lag = sub(T0_max, 4, pOverflow); + + temp1 = add(T0, T0, pOverflow); + temp2 = add(temp1, T0, pOverflow); + uplag = add(temp2, T0_frac, pOverflow); + + i = sub(tmp_lag, 2, pOverflow); + temp1 = add(i, i, pOverflow); + tmp_ind = add(temp1, i, pOverflow); + + temp1 = sub(tmp_ind, uplag, pOverflow); + if (temp1 >= 0) + { + temp1 = sub(T0, tmp_lag, pOverflow); + index = add(temp1, 5, pOverflow); + } + else + { + + i = add(tmp_lag, 1, pOverflow); + temp1 = add(i, i, pOverflow); + i = add(temp1, i, pOverflow); + + if (sub(i, uplag, pOverflow) > 0) + { + temp1 = sub(uplag, tmp_ind, pOverflow); + index = add(temp1, 3, pOverflow); + } + else + { + temp1 = sub(T0, tmp_lag, pOverflow); + index = add(temp1, 11, pOverflow); + } + } + + } /* end if (encoding with 4 bit resolution) */ + } /* end if (second of fourth subframe) */ + + return index; +} + + + |