ets_to_if2.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/ets_to_if2.c
 Funtions: ets_to_if2

     Date: 01/23/2002

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

 Description: Added new method of formatting the frame for modes greater than
              eight. This is to improve speed and was done per review comments.
              bitreorder.h was changed to bitreorder_tab.h

 Description: Removed the #define of 244 for MAX_NUM_BITS since it was not
              used in this function and should not have been defined in this
              local way.

 Description: Added IF statement around packing of first octet for the case
              where frame_type_3gpp >= AMR_SID.

 Description: Fixed bug that causes code to overwrite the memory location
              one past the last location of the IF2 output buffer.

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

 Description:

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

/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "frame_type_3gpp.h"
#include "ets_to_if2.h"
#include "typedef.h"
#include "bitreorder_tab.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: ets_to_if2
------------------------------------------------------------------------------
 INPUT AND OUTPUT DEFINITIONS

 Inputs:
    frame_type_3gpp = decoder speech bit rate (enum Frame_Type_3GPP)
    ets_input_ptr   = pointer to input encoded speech bits in ETS format (Word16)
    if2_output_ptr  = pointer to output encoded speech bits in IF2 format (UWord8)

 Outputs:
    if2_output_ptr  = pointer to encoded speech bits in the IF2 format (UWord8)

 Returns:
    None

 Global Variables Used:
    None

 Local Variables Needed:
    None

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

 This function performs a transformation on the data buffers. It converts the
 data format from ETS (European Telecommunication Standard) to IF2. ETS format
 has the encoded speech bits each separate with only one bit stored in each
 word. IF2 is the storage format where the frame type is in the first four bits
 of the first byte. The upper four bits of that byte contain the first four
 encoded speech bits for the frame. The following bytes contain the rest of
 the encoded speech bits. The final byte has padded zeros  to make the frame
 byte aligned.
------------------------------------------------------------------------------
 REQUIREMENTS

 None

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

AMR Speech Codec Frame Structure", 3GPP TS 26.101 version 4.1.0 Release 4, June 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]

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

void ets_to_if2(
    enum Frame_Type_3GPP frame_type_3gpp,
    Word16 *ets_input_ptr,
    UWord8 *if2_output_ptr)
{
    Word16  i;
    Word16  k;
    Word16  j = 0;
    Word16 *ptr_temp;
    Word16  bits_left;
    UWord8  accum;

    if (frame_type_3gpp < AMR_SID)
    {
        if2_output_ptr[j++] = (UWord8)(frame_type_3gpp) |
                              (ets_input_ptr[reorderBits[frame_type_3gpp][0]] << 4) |
                              (ets_input_ptr[reorderBits[frame_type_3gpp][1]] << 5) |
                              (ets_input_ptr[reorderBits[frame_type_3gpp][2]] << 6) |
                              (ets_input_ptr[reorderBits[frame_type_3gpp][3]] << 7);

        for (i = 4; i < numOfBits[frame_type_3gpp] - 7;)
        {
            if2_output_ptr[j]  =
                (UWord8) ets_input_ptr[reorderBits[frame_type_3gpp][i++]];
            if2_output_ptr[j] |=
                (UWord8) ets_input_ptr[reorderBits[frame_type_3gpp][i++]] << 1;
            if2_output_ptr[j] |=
                (UWord8) ets_input_ptr[reorderBits[frame_type_3gpp][i++]] << 2;
            if2_output_ptr[j] |=
                (UWord8) ets_input_ptr[reorderBits[frame_type_3gpp][i++]] << 3;
            if2_output_ptr[j] |=
                (UWord8) ets_input_ptr[reorderBits[frame_type_3gpp][i++]] << 4;
            if2_output_ptr[j] |=
                (UWord8) ets_input_ptr[reorderBits[frame_type_3gpp][i++]] << 5;
            if2_output_ptr[j] |=
                (UWord8) ets_input_ptr[reorderBits[frame_type_3gpp][i++]] << 6;
            if2_output_ptr[j++] |=
                (UWord8) ets_input_ptr[reorderBits[frame_type_3gpp][i++]] << 7;
        }

        bits_left = 4 + numOfBits[frame_type_3gpp] -
                    ((4 + numOfBits[frame_type_3gpp]) & 0xFFF8);

        if (bits_left != 0)
        {
            if2_output_ptr[j] = 0;

            for (k = 0; k < bits_left; k++)
            {
                if2_output_ptr[j] |=
                    (UWord8) ets_input_ptr[reorderBits[frame_type_3gpp][i++]] << k;
            }
        }
    }
    else
    {
        if (frame_type_3gpp != AMR_NO_DATA)
        {
            /* First octet contains 3GPP frame type and */
            /* first 4 bits of encoded parameters       */
            if2_output_ptr[j++] = (UWord8)(frame_type_3gpp) |
                                  (ets_input_ptr[0] << 4) | (ets_input_ptr[1] << 5) |
                                  (ets_input_ptr[2] << 6) | (ets_input_ptr[3] << 7);
            ptr_temp = &ets_input_ptr[4];

            bits_left = ((4 + numOfBits[frame_type_3gpp]) & 0xFFF8);

            for (i = (bits_left - 7) >> 3; i > 0; i--)
            {
                accum  = (UWord8) * (ptr_temp++);
                accum |= (UWord8) * (ptr_temp++) << 1;
                accum |= (UWord8) * (ptr_temp++) << 2;
                accum |= (UWord8) * (ptr_temp++) << 3;
                accum |= (UWord8) * (ptr_temp++) << 4;
                accum |= (UWord8) * (ptr_temp++) << 5;
                accum |= (UWord8) * (ptr_temp++) << 6;
                accum |= (UWord8) * (ptr_temp++) << 7;

                if2_output_ptr[j++] = accum;
            }

            bits_left = 4 + numOfBits[frame_type_3gpp] - bits_left;

            if (bits_left != 0)
            {
                if2_output_ptr[j] = 0;

                for (i = 0; i < bits_left; i++)
                {
                    if2_output_ptr[j] |= (ptr_temp[i] << i);
                }
            }
        }
        else
        {
            /* When there is no data, LSnibble of first octet */
            /* is the 3GPP frame type, MSnibble is zeroed out */
            if2_output_ptr[j++] = (UWord8)(frame_type_3gpp);
        }

    }

    return;
}