homing.c

GSM中半速率语音编解码源码

/**************************************************************************
 *
 *   File Name:  homing.c
 *
 *   Purpose:
 *      This file contains the following functions:
 *
 *      decoderHomingFrameTest() - checks if a frame of input speech
 *                                 parameters matches the Decoder Homing
 *                                 Frame pattern.
 *
 *      decoderReset() - called by resetDec() to reset all of the state
 *                       variables for the decoder
 *
 *      encoderHomingFrameTest() - checks if a frame of input samples
 *                                 matches the Encoder Homing Frame pattern.
 *
 *      encoderReset() - called by resetEnc() to reset all the state
 *                       variables for the encoder.
 *
 *      resetDec() - calls functions to reset the state variables for the
 *                   decoder, and for the receive DTX and Comfort Noise.
 *
 *      resetEnc() - calls functions to reset the state variables for the
 *                   encoder and VAD, and for the transmit DTX and
 *                   Comfort Noise.
 *
 *      dtxResetTx() - called by resetEnc() to reset all of the transmit
 *                     DTX and Comfort Noise state variables
 *
 *      dtxResetRx() - called by resetDec() to reset all of the receive
 *                     DTX and Comfort Noise state variables
 *
 **************************************************************************/

/*_________________________________________________________________________
 |                                                                         |
 |                              Include Files                              |
 |_________________________________________________________________________|
*/

#include "typedefs.h"
#include "vad.h"
#include "dtx.h"
#include "homing.h"

/*_________________________________________________________________________
 |                                                                         |
 |                              Local Defines                              |
 |_________________________________________________________________________|
*/

#define EHF_MASK 0x0008                /* Encoder Homing Frame pattern */
#define LMAX 142                       /* largest lag (integer sense) */
#define CG_INT_MACS 6                  /* Number of multiply-accumulates in
                                        * one interpolation           */
#define NUM_CLOSED 3                   /* maximum number of lags searched */
#define LPCSTARTINDEX 25               /* where the LPC analysis window
                                        * starts                        */
#define INBUFFSZ LPCSTARTINDEX + A_LEN /* input buffer size */


#define LTP_LEN         147            /* maximum ltp lag */
#define LSMAX           (LMAX + CG_INT_MACS/2)
#define HNW_BUFF_LEN    LSMAX


/***************************************************************************
 *
 *   FUNCTION NAME:  decoderHomingFrameTest
 *
 *   PURPOSE:
 *      Checks if a frame of input speech parameters matches the Decoder
 *      Homing Frame pattern, which is:
 *
 *      parameter  decimal value  hexidecimal value
 *      ---------  -------------  -----------------
 *      R0         0              0x0000
 *      LPC1       881            0x0371
 *      LPC2       350            0x015E
 *      LPC3       195            0x00c3
 *      INT_LPC    1              0x0001
 *      MODE       0              0x0000
 *      CODE1_1    71             0x0047
 *      CODE2_1    74             0x004a
 *      GSP0_1     0              0x0000
 *      CODE1_2    9              0x0009
 *      CODE2_2    38             0x0026
 *      GSP0_2     7              0x0007
 *      CODE1_3    0              0x0000
 *      CODE2_3    0              0x0000
 *      GSP0_3     0              0x0000
 *      CODE1_4    0              0x0000
 *      CODE2_4    0              0x0000
 *      GSP0_4     0              0x0000
 *
 *   INPUT:
 *      pswSpeechPara[] - one frame of speech parameters
 *                        in decoder input format
 *
 *      iLastPara - the number of consecutive parameters in 
 *                  pswSpeechPara[] to match.
 *
 *   OUTPUT:
 *      None
 *
 *   RETURN:
 *      0       input frame does not match the Decoder Homing Frame pattern.
 *      1       input frame matches the Decoder Homing Frame pattern.
 *
 *   REFERENCES: Sub-clause 10 of GSM Recomendation 06.02
 *
 *   KEYWORDS:
 *      pswSpeechPara
 **************************************************************************/

int    decoderHomingFrameTest(Shortword pswSpeechPara[], int iLastPara)
{
  /* the n[] array contains the number of bits in each speech parameter */
  static int n[] = {5, 11, 9, 8, 1, 2, 7, 7, 5, 7, 7, 5, 7, 7, 5, 7, 7, 5};

  static Shortword dhf_mask[] =
  {
    0x0000,                            /* R0      */
    0x0371,                            /* LPC1    */
    0x015E,                            /* LPC2    */
    0x00c3,                            /* LPC3    */
    0x0001,                            /* INT_LPC */
    0x0000,                            /* MODE    */
    0x0047,                            /* CODE1_1 */
    0x004a,                            /* CODE2_1 */
    0x0000,                            /* GSP0_1  */
    0x0009,                            /* CODE1_2 */
    0x0026,                            /* CODE2_2 */
    0x0007,                            /* GSP0_2  */
    0x0000,                            /* CODE1_3 */
    0x0000,                            /* CODE2_3 */
    0x0000,                            /* GSP0_3  */
    0x0000,                            /* CODE1_4 */
    0x0000,                            /* CODE2_4 */
    0x0000                             /* GSP0_4  */
  };

  int    i;
  int    j;

  for (i = 0; i < iLastPara; i++)
  {
    j = ((pswSpeechPara[i] & ~(~0 << n[i])) ^ dhf_mask[i]);
    if (j)
      break;
  }

  return !j;
}


/***************************************************************************
 *
 *   FUNCTION NAME:  decoderReset
 *
 *   PURPOSE:
 *      resets all of the state variables for the decoder
 *
 *   INPUT:
 *      None
 *
 *   OUTPUT:
 *      None
 *
 *   RETURN:
 *      None
 *
 *   REFERENCES: Sub-clause 10 of GSM Recomendation 06.02
 *
 *   KEYWORDS:
 **************************************************************************/

void   decoderReset(void)
{
/*_________________________________________________________________________
 |                                                                         |
 |   External declarations for decoder variables which need to be reset    |
 |_________________________________________________________________________|
*/

  /* variables defined in sp_dec.c */
  /* ----------------------------- */

  extern Shortword gswPostFiltAgcGain,
         gpswPostFiltStateNum[NP],
         gpswPostFiltStateDenom[NP],
         swPostEmphasisState,
         pswSynthFiltState[NP],
         pswOldFrmKsDec[NP],
         pswOldFrmAsDec[NP],
         pswOldFrmPFNum[NP],
         pswOldFrmPFDenom[NP],
         swOldR0Dec,
         pswLtpStateBaseDec[LTP_LEN + S_LEN],
         pswPPreState[LTP_LEN + S_LEN];

  extern Shortword swMuteFlagOld;      /* error concealment */


  /* variables defined in err_conc.c *//* error concealment */
  /* ------------------------------- *//* error concealment */

  extern Longword plSubfrEnergyMem[4]; /* error concealment */
  extern Shortword swLevelMem[4],
         lastR0,                       /* error concealment */
         pswLastGood[18],              /* error concealment */
         swState,
         swLastFlag;                   /* error concealment */

/*_________________________________________________________________________
 |                                                                         |
 |   Automatic Variables                                                   |
 |_________________________________________________________________________|
*/

  int    i;

/*_________________________________________________________________________
 |                                                                         |
 |   Executable code                                                       |
 |_________________________________________________________________________|
*/

  /* reset all the decoder state variables */
  /* ------------------------------------- */

  swOldR0Dec = 0;

  gswPostFiltAgcGain = 0;

  swPostEmphasisState = 0;

  for (i = 0; i < NP; i++)
  {
    gpswPostFiltStateNum[i] = 0;
    gpswPostFiltStateDenom[i] = 0;
    pswSynthFiltState[i] = 0;
    pswOldFrmKsDec[i] = 0;
    pswOldFrmAsDec[i] = 0;
    pswOldFrmPFNum[i] = 0;
    pswOldFrmPFDenom[i] = 0;
  }

  for (i = 0; i < (LTP_LEN + S_LEN); i++)
  {
    pswLtpStateBaseDec[i] = 0;
    pswPPreState[i] = 0;
  }


  /* reset all the error concealment state variables */
  /* ----------------------------------------------- */

  swMuteFlagOld = 0;

  lastR0 = 0;
  swState = 7;
  swLastFlag = 0;
  for (i = 0; i < 3; i++)
  {
    plSubfrEnergyMem[i] = 80;
    swLevelMem[i] = -72;
  }
  for (i = 0; i < 18; i++)
  {
    pswLastGood[i] = 0;
  }


}

/***************************************************************************
 *
 *   FUNCTION NAME:  encoderHomingFrameTest
 *
 *   PURPOSE:
 *      Checks if a frame of input samples matches the Encoder Homing Frame
 *      pattern, which is 0x0008 for all 160 samples in the frame.
 *
 *   INPUT:
 *      pswSpeech[]    one frame of speech samples
 *
 *   OUTPUT:
 *      None
 *
 *   RETURN:
 *      0       input frame does not match the Encoder Homing Frame pattern.
 *      1       input frame matches the Encoder Homing Frame pattern.
 *
 *   REFERENCES: Sub-clause 10 of GSM Recomendation 06.02
 *
 *   KEYWORDS:
 *      pswSpeech
 **************************************************************************/

int    encoderHomingFrameTest(Shortword pswSpeech[])
{
  int    i;
  Shortword j;

  for (i = 0; i < F_LEN; i++)
  {
    j = pswSpeech[i] ^ EHF_MASK;
    if (j)
      break;
  }

  return !j;
}

/***************************************************************************
 *
 *   FUNCTION NAME:  encoderReset
 *
 *   PURPOSE:
 *      resets all of the state variables for the encoder
 *
 *   INPUT:
 *      None