vad1.cpp

实现3GPP的GSM中AMR语音的CODECS。

/* ------------------------------------------------------------------
 * Copyright (C) 2008 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/vad1.c
 Functions:

     Date: 02/04/2002

------------------------------------------------------------------------------
 REVISION HISTORY

 Description: Updated template used to PV coding template.
 Changed to accept the pOverflow flag for EPOC compatibility.

 Description: Made changes per review comments
 (1) Removed include of "count.h"
 (2) Replaced "basic_op.h" with individual include files
 (3) Removed some unnecessary instances of sub().

 Description:  Replaced OSCL mem type functions and eliminated include
               files that now are chosen by OSCL definitions

 Description:  Replaced "int" and/or "char" with OSCL defined types.

 Description: Changed round function name to pv_round to avoid conflict with
              round function in C standard library.

 Description:

------------------------------------------------------------------------------
 MODULE DESCRIPTION


------------------------------------------------------------------------------
*/

/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "vad.h"
#include "typedef.h"
#include "shr.h"
#include "basic_op.h"
#include "cnst_vad.h"
#include "oscl_mem.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: first_filter_stage
------------------------------------------------------------------------------
 INPUT AND OUTPUT DEFINITIONS

 Inputs:
    data -- array of type Word16 -- filter memory
    in   -- array of type Word16 -- input signal

 Outputs:
    data -- array of type Word16 -- filter memory
    out  -- array of type Word16 -- output values, every other
                                    output is low-pass part and
                                    other is high-pass part every

    pOverflow -- pointer to type Flag -- overflow indicator

 Returns:
    None

 Global Variables Used:
    None

 Local Variables Needed:
    None

------------------------------------------------------------------------------
 FUNCTION DESCRIPTION

 Purpose      : Scale input down by one bit. Calculate 5th order
                half-band lowpass/highpass filter pair with
                decimation.
------------------------------------------------------------------------------
 REQUIREMENTS

 None

------------------------------------------------------------------------------
 REFERENCES

 vad1.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]

------------------------------------------------------------------------------
*/

static void first_filter_stage(
    Word16 in[],      /* i   : input signal                  */
    Word16 out[],     /* o   : output values, every other    */
    /*       output is low-pass part and   */
    /*       other is high-pass part every */
    Word16 data[],    /* i/o : filter memory                 */
    Flag  *pOverflow  /* o : Flag set when overflow occurs   */
)
{
    Word16 temp0;
    Word16 temp1;
    Word16 temp2;
    Word16 temp3;
    Word16 i;
    Word16 data0;
    Word16 data1;

    data0 = data[0];
    data1 = data[1];

    for (i = 0; i < FRAME_LEN / 4; i++)
    {
        temp0 = mult(COEFF5_1, data0, pOverflow);
        temp1 = shr(in[4*i+0], 2, pOverflow);
        temp0 = sub(temp1, temp0, pOverflow);

        temp1 = mult(COEFF5_1, temp0, pOverflow);
        temp1 = add(data0, temp1, pOverflow);

        temp3 = mult(COEFF5_2, data1, pOverflow);
        temp2 = shr(in[4*i+1], 2, pOverflow);

        temp3 = sub(temp2, temp3, pOverflow);

        temp2 = mult(COEFF5_2, temp3, pOverflow);
        temp2 = add(data1, temp2, pOverflow);

        out[4*i+0] = add(temp1, temp2, pOverflow);
        out[4*i+1] = sub(temp1, temp2, pOverflow);

        temp1 = mult(COEFF5_1, temp0, pOverflow);
        temp2 = shr(in[4*i+2], 2, pOverflow);
        data0 = sub(temp2, temp1, pOverflow);

        temp1 = mult(COEFF5_1, data0, pOverflow);
        temp1 = add(temp0, temp1, pOverflow);

        data1 = mult(COEFF5_2, temp3, pOverflow);
        temp2 = shr(in[4*i+3], 2, pOverflow);
        data1 = sub(temp2, data1, pOverflow);

        temp2 = mult(COEFF5_2, data1, pOverflow);
        temp2 = add(temp3, temp2, pOverflow);

        out[4*i+2] = add(temp1, temp2, pOverflow);
        out[4*i+3] = sub(temp1, temp2, pOverflow);
    }

    data[0] = data0;
    data[1] = data1;
}


/*
------------------------------------------------------------------------------
 FUNCTION NAME: filter5
------------------------------------------------------------------------------
 INPUT AND OUTPUT DEFINITIONS

 Inputs:
    in0 -- array of type Word16 -- input values; output low-pass part
    in1 -- array of type Word16 -- input values; output high-pass part
    data -- array of type Word16 -- updated filter memory

 Outputs:
    in0 -- array of type Word16 -- input values; output low-pass part
    in1 -- array of type Word16 -- input values; output high-pass part
    data -- array of type Word16 -- updated filter memory
    pOverflow -- pointer to type Flag -- overflow indicator

 Returns:
    None

 Global Variables Used:
    None

 Local Variables Needed:
    None

------------------------------------------------------------------------------
 FUNCTION DESCRIPTION

 Purpose      : Fifth-order half-band lowpass/highpass filter pair with
                decimation.
------------------------------------------------------------------------------
 REQUIREMENTS

 None

------------------------------------------------------------------------------
 REFERENCES

 vad1.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]

------------------------------------------------------------------------------
*/

static void filter5(Word16 *in0,    /* i/o : input values; output low-pass part  */
                    Word16 *in1,    /* i/o : input values; output high-pass part */
                    Word16 data[],  /* i/o : updated filter memory               */
                    Flag  *pOverflow  /* o : Flag set when overflow occurs       */
                   )
{
    Word16 temp0;
    Word16 temp1;
    Word16 temp2;

    temp0 = mult(COEFF5_1, data[0], pOverflow);
    temp0 = sub(*in0, temp0, pOverflow);

    temp1 = mult(COEFF5_1, temp0, pOverflow);
    temp1 = add(data[0], temp1, pOverflow);
    data[0] = temp0;

    temp0 = mult(COEFF5_2, data[1], pOverflow);
    temp0 = sub(*in1, temp0, pOverflow);

    temp2 = mult(COEFF5_2, temp0, pOverflow);
    temp2 = add(data[1], temp2, pOverflow);

    data[1] = temp0;

    temp0 = add(temp1, temp2, pOverflow);
    *in0 = shr(temp0, 1, pOverflow);

    temp0 = sub(temp1, temp2, pOverflow);
    *in1 = shr(temp0, 1, pOverflow);
}




/*
------------------------------------------------------------------------------
 FUNCTION NAME: filter3
------------------------------------------------------------------------------
 INPUT AND OUTPUT DEFINITIONS


 Inputs:
    in0 -- array of type Word16 -- input values; output low-pass part
    in1 -- array of type Word16 -- input values; output high-pass part
    data -- array of type Word16 -- updated filter memory

 Outputs:
    in0 -- array of type Word16 -- input values; output low-pass part
    in1 -- array of type Word16 -- input values; output high-pass part
    data -- array of type Word16 -- updated filter memory
    pOverflow -- pointer to type Flag -- overflow indicator

 Returns:
    None

 Global Variables Used:
    None

 Local Variables Needed:
    None

------------------------------------------------------------------------------
 FUNCTION DESCRIPTION

 Purpose      : Third-order half-band lowpass/highpass filter pair with
                decimation.
------------------------------------------------------------------------------
 REQUIREMENTS

 None

------------------------------------------------------------------------------
 REFERENCES

 vad1.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]

------------------------------------------------------------------------------
*/

static void filter3(
    Word16 *in0,      /* i/o : input values; output low-pass part  */
    Word16 *in1,      /* i/o : input values; output high-pass part */
    Word16 *data,     /* i/o : updated filter memory               */
    Flag  *pOverflow  /* o : Flag set when overflow occurs         */
)
{
    Word16 temp1;
    Word16 temp2;

    temp1 = mult(COEFF3, *data, pOverflow);
    temp1 = sub(*in1, temp1, pOverflow);

    temp2 = mult(COEFF3, temp1, pOverflow);
    temp2 = add(*data, temp2, pOverflow);

    *data = temp1;

    temp1 = sub(*in0, temp2, pOverflow);

    *in1 = shr(temp1, 1, pOverflow);

    temp1 = add(*in0, temp2, pOverflow);

    *in0 = shr(temp1, 1, pOverflow);
}




/*
------------------------------------------------------------------------------
 FUNCTION NAME: level_calculation
------------------------------------------------------------------------------
 INPUT AND OUTPUT DEFINITIONS

 Inputs:
    data -- array of type Word16 -- signal buffer
    sub_level -- pointer to type Word16 -- level calculated at the end of
                                           the previous frame

    count1 -- Word16 -- number of samples to be counted
    count2 -- Word16 -- number of samples to be counted