sp_dec.cpp

实现3GPP的GSM中AMR语音的CODECS。

 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 Speech_Decode_Frame_reset(void *state_data)
{

    Speech_Decode_FrameState *state =
        (Speech_Decode_FrameState *) state_data;

    if (state_data ==  NULL)
    {
        /*  fprintf(stderr, "Speech_Decode_Frame_reset:
                             invalid parameter\n");  */
        return (-1);
    }

    Decoder_amr_reset(&(state->decoder_amrState), MR475);
    Post_Filter_reset(&(state->post_state));
    Post_Process_reset(&(state->postHP_state));

    state->prev_mode = MR475;

    return (0);
}

/****************************************************************************/

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

 Inputs:
    state = pointer to an array of pointers to structures of type
            Speech_Decode_FrameState

 Outputs:
    state contents is set to NULL

 Returns:
    None

 Global Variables Used:
    None

 Local Variables Needed:
    None

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

 This function frees up the memory used for the state memory of the GSM AMR
 decoder.

------------------------------------------------------------------------------
 REQUIREMENTS

 None

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

 sp_dec.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001

------------------------------------------------------------------------------
 PSEUDO-CODE

 Note: The original function name of Speech_Decode_Frame_exit was changed to
       GSMDecodeFrameExit in the Code section.

void Speech_Decode_Frame_exit (Speech_Decode_FrameState **state)
{
  if (state == NULL || *state == NULL)
      return;

  Decoder_amr_exit(&(*state)->decoder_amrState);
  Post_Filter_exit(&(*state)->post_state);
  Post_Process_exit(&(*state)->postHP_state);

  setCounter((*state)->complexityCounter);
  WMOPS_output(0);
  setCounter(0); // set counter to global counter

  // deallocate memory
  free(*state);
  *state = NULL;

  return;
}

------------------------------------------------------------------------------
 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 GSMDecodeFrameExit(void **state_data)
{

    Speech_Decode_FrameState **state =
        (Speech_Decode_FrameState **) state_data;

    if (state == NULL || *state == NULL)
    {
        return;
    }

    /* deallocate memory */
    oscl_free(*state);
    *state = NULL;

    return;
}

/****************************************************************************/

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

 Inputs:
    st = pointer to structures of type Speech_Decode_FrameState
    mode = GSM AMR codec mode (enum Mode)
    serial = pointer to the serial bit stream buffer (unsigned char)
    frame_type = GSM AMR receive frame type (enum RXFrameType)
    synth = pointer to the output synthesis speech buffer (Word16)

 Outputs:
    synth contents are truncated to 13 bits if NO13BIT is not defined,
      otherwise, its contents are left at 16 bits

 Returns:
    return_value = set to zero (int)

 Global Variables Used:
    None

 Local Variables Needed:
    None

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

 This function is the entry point to the GSM AMR decoder. The following
 operations are performed on one received frame: First, the codec
 parameters are parsed from the buffer pointed to by serial according to
 frame_type. Then the AMR decoder is invoked via a call to Decoder_amr. Post
 filtering of the decoded data is done via a call to Post_Filter function.
 Lastly, the decoded data is post-processed via a call to Post_Process
 function. If NO13BIT is not defined, the contents of the buffer pointed to
 by synth is truncated to 13 bits. It remains unchanged otherwise.

------------------------------------------------------------------------------
 REQUIREMENTS

 None

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

 sp_dec.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001

------------------------------------------------------------------------------
 PSEUDO-CODE

 Note: The original function name of Speech_Decode_Frame_exit was changed to
       GSMFrameDecode in the Code section.

int Speech_Decode_Frame (
    Speech_Decode_FrameState *st, // io: post filter states
    enum Mode mode,               // i : AMR mode
    Word16 *serial,               // i : serial bit stream
    enum RXFrameType frame_type,  // i : Frame type
    Word16 *synth                 // o : synthesis speech (postfiltered
                                  //     output)
)
{
  Word16 parm[MAX_PRM_SIZE + 1];  // Synthesis parameters
  Word16 Az_dec[AZ_SIZE];         // Decoded Az for post-filter
                                  // in 4 subframes

#if !defined(NO13BIT)
  Word16 i;
#endif

  setCounter(st->complexityCounter);
  Reset_WMOPS_counter ();          // reset WMOPS counter for the new frame

  // Serial to parameters
  if ((frame_type == RX_SID_BAD) ||
      (frame_type == RX_SID_UPDATE)) {
    // Override mode to MRDTX
    Bits2prm (MRDTX, serial, parm);
  } else {
    Bits2prm (mode, serial, parm);
  }

  // Synthesis
  Decoder_amr(st->decoder_amrState, mode, parm, frame_type,
              synth, Az_dec);

  Post_Filter(st->post_state, mode, synth, Az_dec);   // Post-filter

  // post HP filter, and 15->16 bits
  Post_Process(st->postHP_state, synth, L_FRAME);

#if !defined(NO13BIT)
  // Truncate to 13 bits
  for (i = 0; i < L_FRAME; i++)
  {
     synth[i] = synth[i] & 0xfff8;
  }
#endif

  setCounter(0); // set counter to global counter

  return 0;
}


------------------------------------------------------------------------------
 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 GSMFrameDecode(
    Speech_Decode_FrameState *st, /* io: post filter states                */
    enum Mode mode,               /* i : AMR mode                          */
    Word16 *serial,               /* i : serial bit stream                 */
    enum RXFrameType frame_type,  /* i : Frame type                        */
    Word16 *synth)                /* o : synthesis speech (postfiltered    */
/*     output)                           */

{
    Word16 parm[MAX_PRM_SIZE + 1];  /* Synthesis parameters                */
    Word16 Az_dec[AZ_SIZE];         /* Decoded Az for post-filter          */
    /* in 4 subframes                      */
    Flag *pOverflow = &(st->decoder_amrState.overflow);  /* Overflow flag  */

#if !defined(NO13BIT)
    Word16 i;
#endif

    /* Serial to parameters   */
    if ((frame_type == RX_SID_BAD) ||
            (frame_type == RX_SID_UPDATE))
    {
        /* Override mode to MRDTX */
        Bits2prm(MRDTX, serial, parm);
    }
    else
    {
        Bits2prm(mode, serial, parm);
    }

    /* Synthesis */
    Decoder_amr(
        &(st->decoder_amrState),
        mode,
        parm,
        frame_type,
        synth,
        Az_dec);

    /* Post-filter */
    Post_Filter(
        &(st->post_state),
        mode,
        synth,
        Az_dec,
        pOverflow);

    /* post HP filter, and 15->16 bits */
    Post_Process(
        &(st->postHP_state),
        synth,
        L_FRAME,
        pOverflow);

#if !defined(NO13BIT)
    /* Truncate to 13 bits */
    for (i = 0; i < L_FRAME; i++)
    {
        synth[i] = synth[i] & 0xfff8;
    }
#endif

    return;
}