eid.c

Reference Implementation of G.711 standard and other voice codecs

        Parameters:    
        ~~~~~~~~~~~  
        EID: ............. (In) Pointer to EID-struct 
        threshold: ....... (In) threshold 
        current_state: ... (In) current state ('G' or 'B') 
        next_state: ...... (In) next state ('G' or 'B') 

        Return value:    none.
        ~~~~~~~~~~~~~

        Author: <[e-mail]>
        ~~~~~~~

        History:
        ~~~~~~~~
        28.Feb.92 v1.0 Release of 1st version <[e-mail]>

 ============================================================================
*/
void set_GEC_matrix(EID,threshold,current_state,next_state)
SCD_EID *EID;
double threshold;
int /* char */ current_state;
int /* char */ next_state;
{
  int icurr,inext;


  if (toupper(current_state)=='G')
    icurr = 0;
  else
    icurr = 1;

  if (toupper(next_state)=='G')
    inext = 0;
  else
    inext = 1;

  EID->matrix[icurr][inext] = threshold;
}
/* ....................... End of set_GEC_matrix() ....................... */



/*
  ========================================================================== 

        double get_GEC_matrix (SCD_EID *EID, int current_state, int
        ~~~~~~~~~~~~~~~~~~~~~  next_state);
        

        Description:
        ~~~~~~~~~~~~

        Auxiliary function to support saving of channel states.
        Get the state of the Transition Matrix of GEC-model.

        Parameters:    
        ~~~~~~~~~~~  
        EID: ............. (In) Pointer to EID-struct 
        current_state: ... (In) current state ('G' or 'B') 
        next_state: ...... (In) next state ('G' or 'B') 

        Return value:
        ~~~~~~~~~~~~~
        Returns the threshold as a double.

        Author: <[e-mail]>
        ~~~~~~~

        History:
        ~~~~~~~~
        20.Apr.92 v1.0 Release of 1st version <[e-mail]>

 ============================================================================
*/
double get_GEC_matrix(EID,current_state,next_state)
SCD_EID *EID;
int /* char */ current_state;
int /* char */ next_state;
{
   int icurr,inext;


   if (toupper(current_state)=='G')
     icurr = 0;
   else
     icurr = 1;

   if (toupper(next_state)=='G')
     inext = 0;
   else
     inext = 1;

   return(EID->matrix[icurr][inext]);
}
/* ....................... End of get_GEC_matrix() ....................... */


/*
  ========================================================================== 

        void set_GEC_current_state (SCD_EID *EID, int current_state);
        ~~~~~~~~~~~~~~~~~~~~~~~~~~

        Description:
        ~~~~~~~~~~~~

        Auxiliary function to support setting the current channel state.

        Parameters:    
        ~~~~~~~~~~~  
        EID: ............. (In) Pointer to EID-struct 
        current_state: ... (In) current state ('G' or 'B') 

        Return value:     none.
        ~~~~~~~~~~~~~

        Author: <[e-mail]>
        ~~~~~~~

        History:
        ~~~~~~~~
        20.Apr.92 v1.0 Release of 1st version <[e-mail]>

 ============================================================================
*/
void set_GEC_current_state(EID,current_state)
SCD_EID *EID;
int /* char */ current_state;
{
  if (toupper(current_state)=='G')
    EID->current_state = 0L;
  else
    EID->current_state = 1L;
}
/* ................... End of set_GEC_current_state() ................... */


/*
  ========================================================================== 

        char get_GEC_current_state (SCD_EID *EID); 
        ~~~~~~~~~~~~~~~~~~~~~~~~~~

        Description:
        ~~~~~~~~~~~~

        Function to get the channel current state.

        Parameters:    
        ~~~~~~~~~~~  
        EID: ..... pointer to state variable;

        Return value:
        ~~~~~~~~~~~~~
        Return the current state (Good or Bad).

        Author: <[e-mail]>
        ~~~~~~~

        History:
        ~~~~~~~~
        20.Apr.92 v1.0 Release of 1st version <[e-mail]>

 ============================================================================ 
*/
char get_GEC_current_state(EID)
SCD_EID *EID; 
{
  if (EID->current_state==0L)
    return('G');
  else
    return('B');
}
/* .................... End of get_GEC_current_state() .................... */


/*
  ============================================================================ 

        BURST_EID *open_burst_eid (long index);
        ~~~~~~~~~~~~~~~~~~~~~~~~~

        Description:
        ~~~~~~~~~~~~

        Allocate memory for BURST_EID struct and setup the transition
        matrix according the selected bit error rate.

        Parameters:  
        ~~~~~~~~~~~
        index: ..... (In) Index for model vector parameter
			    1 = 1%, 3=3%, 5=5% 

        Return value:
        ~~~~~~~~~~~~~
        Returns a pointer to struct BURST_EID;

        Author: 
        ~~~~~~~
	Cliff Halevi
        Bellcore, NVC 5F 319	Phone: [phone]
        100 Schultz Drive	Fax:   [phone]
        Red Bank, NJ 07701.	email: [e-mail]

        Vijay Varma
        Bellcore NVC 3X-325	Phone: [phone]
        331 Newman Springs Road	Fax:   [phone]
        Red Bank, NJ 07701.	email: [e-mail]

	Gerhard Schroeder .....

        History:
        ~~~~~~~~
        04/Aug/93 v.1.0 Created

 ============================================================================
*/
BURST_EID   *open_burst_eid (index)
long index;
{
  BURST_EID *burst_eid;
  time_t t1;
  long i;

  /* Allocate EID structure */
   if ((burst_eid=(BURST_EID *)malloc(sizeof(BURST_EID)))==0L) 
	    return((BURST_EID *)0);

  /* Preset of the random generator seed with current system time */
#ifdef PORT_TEST
    t1 = 314159265;
#else
    time(&t1);
#endif

    burst_eid->seedptr = (unsigned long) t1;
    for (i=0;  i<MODEL_SIZE;  i++)
    {
      burst_eid->internal[i] = 0;
    }
    burst_eid->s_new = 0;
    
    switch (index)
    {
    	case 1:
	    burst_eid->index = 0;
	    break;
    	case 3:
	    burst_eid->index = 1;
	    break;
    	case 5:
	    burst_eid->index = 2;
	    break;
    	case 10:
	    burst_eid->index = 3;
	    break;
    	case 15:
	    burst_eid->index = 4;
	    break;
    	default:
	    fprintf(stderr, " Using default error rate of 1 %%\n");
	    burst_eid->index = 0;
	    break;
    }
    
#ifdef DEBUG
    /*	 
    **  Print out the selected coefficient vector
    */	 
    for (i=0;  i< MODEL_SIZE;  i++)
    {
      printf ("p[%2d]=%f\n", i,prob[burst_eid->index][i]);
    }
#endif

   /* Return BURST_EID structure */
    return (burst_eid);
}
/* .................... End of open_burst_eid() .................... */


/*
  ============================================================================ 

        double FER_generator_burst (BURST_EID *state);
        ~~~~~~~~~~~~~~~~~~~~~~~~~~

        Description:
        ~~~~~~~~~~~~

        Generate a double indicating whether the current frame should be
        considered good or bad..

        Parameters:  
        ~~~~~~~~~~~
        state: ..... (In/Out) State variable describing the channel.

        Return value:
        ~~~~~~~~~~~~~
        Returns 0 on a good-frame indication and 1 if the current frame
        is to be considered a bad frame.

        Author: 
        ~~~~~~~
	Gerhard Schroeder
	FI-DBP Telekom            Tel: 	[phone]
	Am Kavalleriesand 3       Fax: 	[phone]
	D-64295 Darmstadt         E-mail: [e-mail]
	GERMANY

        History:
        ~~~~~~~~
        04/Aug/93 v1.0 Created
	26.Jan.98 v3.0 Corrected bug for 64-bit operating systems (where 
                       longs have 64, not 32 bits). Implemented by
                       <[e-mail]>, after bug reported
                       by <[e-mail]>

 ============================================================================
*/
double FER_generator_burst (state)
BURST_EID *state;
{
  long    in;
  double  ran, aux; 
  /* Size in bits (=size in bytes * 8) for long variables*/
  static double bits_in_long = sizeof(long) * 8;

  /* UGST Random number generator */
  state->seedptr = ((unsigned long)69069L * (state->seedptr) +1L);

  /* Return random number as a double in range [0...1] */
#ifdef WAS
  ran = (pow((double)2.0, (double)-32.0) * (double)(state->seedptr));
#else
  ran = (pow((double)2.0, -bits_in_long) * (double)(state->seedptr));
#endif
  aux = prob[state->index][state->s_new];
  in = floor(ran + aux);	/* in = 0 indicates good frame */
                                /* in = 1 indicates bad frame */
  if (in == 0)                    /* If frame is good, */
  {
    /* increment frame counter for state */
    state->internal[state->s_new]++;
    if (state->s_new != 0) state->internal[0]++;
    state->s_new = 0;
  }
  else
    state->s_new++;      /* Else, if frame is bad, increment state */

  return((double) in);
}
/* .................... End of FER_generator_burst() .................... */


/* ********************************************************************* */
/* ********************************************************************* */
/* ************************* ADDED AFTER STL96 ************************* */
/* ********************************************************************* */
/* ********************************************************************* */

/* 
   -------------------------------------------------------------------------
   void reset_burst_eid (BURST_EID *burst_eid);
   ~~~~~~~~~~~~~~~~~~~~

   Reset a BURST_EID structure. By default, only counters are reset;
   if the symbol RESET_SEED_AS_WELL is defined at compilation time,
   the seed is also reset. However, this is not recommended.

   Parameter:
   ~~~~~~~~~~
   burst_eid: .... BURST_EID structure (previously initialized by 
                   open_burst_eid) to be reset.

   Return value: None.
   ~~~~~~~~~~~~~

   Original author: <[e-mail]>
   ~~~~~~~~~~~~~~~~

   History:
   ~~~~~~~~
   15.Aug.97  v.1.0  Created.
   ---------------------------------------------------------------------