ec_rearm( )

---

Example | Errors

Name:	int ec_rearm(chDev)
Inputs:	int chDev	valid channel device handle
Returns:	0 for success -1 for failure
Includes:	srllib.h dxxxlib.h eclib.h
Category:	I/O
Mode:	synchronous

Description

The ec_rearm( ) function temporarily stops streaming of echo-cancelled data from the board and rearms or re-enables the voice activity detector (VAD). The prompt is not affected by this function.

If a VAD event is received and the recognizer determines that the energy was non-speech such as a cough, use this function to re-activate the VAD for the next burst of energy.

Note: The ec_rearm( ) function is intended to be used with VAD enabled and barge-in disabled.

Parameter	Description
chDev	The channel device handle obtained when the CSP-capable device is opened using dx_open( ).

The following scenario describes how the ec_rearm( ) function works:

• After the VAD is triggered, it starts streaming data to the host application.
• The host application determines that this is a false trigger and calls the ec_rearm( ) function.
• Streaming is halted and the VAD is rearmed for the next burst of energy.

Caution: During the time that the VAD is being rearmed, you will not get a VAD event if an energy burst comes in. The time it takes for the VAD to be rearmed varies depending on hardware and operating system used.

Figure2-1 illustrates the rearming concept.

Figure 2-1. Rearming the Voice Activity Detector (VAD)

Example

#include <windows.h>  /* include in Windows applications only; exclude in Linux */
#include <stdio.h>
#include <srllib.h>
#include <dxxxlib.h>
#include <eclib.h>
#include <errno.h>  /* include in Linux applications only; exclude in Windows */ 
main()
{ 
   char  csp_devname[9];
   int   ret, csp_dev, parmval=0;
   SC_TSINFO  sc_tsinfo;   /* Time slot information structure */
   long scts;              /* SCbus time slot */
   int srlmode;            /* Standard Runtime Library mode */
   DX_IOTT iott;           /* I/O transfer table */
   DV_TPT  tptp[1], tpt;   /* termination parameter table */
   DX_XPB xpb;             /* I/O transfer parameter block */ 
 
  /* Set SRL to run in polled mode. */
   srlmode = SR_POLLMODE;
   if (sr_setparm(SRL_DEVICE, SR_MODEID, (void *)&srlmode) == -1) {
      /* process error */
   } 
sprintf(csp_devname,"dxxxB1C1"); 
 
/* Open a voice device. */
csp_dev = dx_open(csp_devname, 0);
if (csp_dev < 0) {
        printf("Error %d in dx_open()\n",csp_dev);  
        exit(-1);
} 
/* Set up ec parameters as needed. 
 * ECCH_VADINITIATED is enabled by default. 
 * Barge-in should be disabled (DXCH_BARGEIN=0) so that prompt 
 * continues to play after energy is detected.
 */
ret = ec_setparm( ... );
if (ret == -1) {
     printf("Error in ec_setparm(). Err Msg = %s, Lasterror = %d\n", 
     ATDV_ERRMSGP(csp_dev), ATDV_LASTERR(csp_dev));          
} 
/* Set up DV_TPT for record */
tpt.tp_type   = IO_EOT;
tpt.tp_termno = DX_MAXTIME;
tpt.tp_length = 60;
tpt.tp_flags  = TF_MAXTIME; 
/* Record data format set to 8-bit Dialogic PCM, 8KHz sampling rate */
xpb.wFileFormat = FILE_FORMAT_VOX;
xpb.wDataFormat = DATA_FORMAT_PCM;
xpb.nSamplesPerSec = DRT_8KHZ;
xpb.wBitsPerSample = 8; 
ret = ec_stream(csp_dev, &tpt, &xpb, &stream_cb, EV_ASYNC | MD_NOGAIN);
if (ret == -1) {
     printf("Error in ec_reciottdata(). Err Msg = %s, Lasterror = %d\n", 
     ATDV_ERRMSGP(csp_dev), ATDV_LASTERR(csp_dev));          
} 
/* Set channel off-hook */
ret = dx_sethook(csp_dev, DX_OFFHOOK, EV_SYNC);
if (ret == -1) {
     printf("Error in dx_sethook(). Err Msg = %s, Lasterror = %d\n", 
     ATDV_ERRMSGP(csp_dev), ATDV_LASTERR(csp_dev));          
} 
/* Set up DX_IOTT */
iott.io_type   = IO_DEV|IO_EOT;
iott.io_bufp   = 0;
iott.io_offset = 0;
iott.io_length = -1; 
/* Set up DV_TPT for play */
dx_clrtpt(&tptp,1);
tptp[0].tp_type   = IO_EOT;
tptp[0].tp_termno = DX_MAXDTMF;
tptp[0].tp_length = 1;
tptp[0].tp_flags  = TF_MAXDTMF; 
/* Open file to be played */
#ifdef WIN32 
if ((iott.io_fhandle = dx_fileopen("sample.vox",O_RDONLY|O_BINARY)) == -1) {
     printf("Error opening sample.vox.\n");
     exit(1);
}
#else
if (( iott.io_fhandle = open("sample.vox",O_RDONLY)) == -1) {
      printf("File open error\n");
      exit(2);
}
#endif 
/* Play prompt message. */
ret = dx_play(csp_dev, &iott, &tptp, EV_ASYNC);
if ( ret == -1) {
     printf("Error playing sample.vox.\n");
     exit(1);
} 
 
/* In the ASR engine section -- pseudocode */
  while (utterance is undesirable) {
     /* Wait for TEC_VAD event */
     while (TEC_VAD event is not received) {
        sr_waitevt(-1);
        ret = sr_getevttype( );
        if (ret == TEC_VAD) {
           /* After TEC_VAD event is received, determine if utterance is desirable */
           if (utterance is undesirable) {
              /* Use ec_rearm( ) to pause streaming and rearm the VAD trigger*/
              ret = ec_rearm(csp_dev);
              if (ret == -1) {
                printf("Error in ec_rearm(). Err Msg = %s, Lasterror = %d\n", 
                ATDV_ERRMSGP(csp_dev), ATDV_LASTERR(csp_dev));          
              } /* end if (ret == -1) */
           } /* end if (utterance is undesirable) */
        } /* end if (ret == TEC_VAD) */
     } /* end while (TEC_VAD event not received) 
  } /* end while (utterance is undesirable) */ 
.
.
. 

Errors

If the function returns -1, use ATDV_LASTERR( ) to return the error code and ATDV_ERRMSGP( ) to return a descriptive error message.

One of the following error codes may be returned:

Error code	Reason
EDX_BADDEV	Device handle is NULL or invalid.
EDX_BADPARM	Parameter is invalid.
EEC_UNSUPPORTED	Device handle is valid but device does not support CSP.

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