live-spot.c¶

This example shows how to run a recognizer on live audio captured from the default audio source.

Instructions¶

Build the sample code. In the same terminal window type the command after the %, then say "voice genie":

% ./bin/live-spot ../../model/spot-voicegenie-enUS-6.5.1-m.snsr
Spotted "voicegenie" at 4.56 seconds.

This example works with any phrasespot recognizer type, so let's create a sequential combination of a wake word and a command set:
```
% ./bin/snsr-edit -vt ../../model/tpl-spot-sequential-1.5.0.snsr \
    -f 0 ../../model/spot-voicegenie-enUS-6.5.1-m.snsr \
    -f 1 ../../model/spot-music-enUS-1.2.0-m.snsr\
    -o spot-vg-music.snsr
Output written to "spot-vg-music.snsr".
```
spot-vg-music.snsr listens for the wake word "voice genie". Once detected, it listens for up to five seconds for a small set of music player commands "play music", "stop music", "previous song", "next song", and "pause music".

Run the live-spot example again and say some of the music commands. Then try "voice genie" followed by one of the commands again:
```
% ./bin/live-spot spot-vg-music.snsr
Spotted "play_music" at 10.32 seconds.
```

stt A VAD combined with either an LVCSR or STT model also works:

% ./bin/snsr-edit -vt ../../model/tpl-vad-lvcsr-3.17.0.snsr \
    -f 0 ../../model/stt-enUS-automotive-medium-2.3.15-pnc.snsr \
    -o vad-stt.snsr
Output written to "vad-stt.snsr".

% ./bin/live-spot vad-stt.snsr
Spotted "Hello world. This is a test sentence." at 2.61 seconds.

Code¶

Available in this TrulyNatural SDK installation at ~/Sensory/TrulyNaturalSDK/7.6.1/sample/c/src/live-spot.c

live-spot.c

/* Sensory Confidential
 * Copyright (C)2016-2025 Sensory, Inc. https://sensory.com/
 *
 * TrulyHandsfree SDK keyword spotting minimal example.
 *------------------------------------------------------------------------------
 */

#include <snsr.h>

#include <stdlib.h>


/* Result callback function, see snsrSetHandler() in main() below.
 * Print the result text and the start time of the first spotted phrase.
 */
static SnsrRC
resultEvent(SnsrSession s, const char *key, void *privateData)
{
  SnsrRC r;
  const char *phrase;
  double begin;

  /* Retrieve the phrase text and start time from the session handle. */
  snsrGetDouble(s, SNSR_RES_BEGIN_MS, &begin);
  r = snsrGetString(s, SNSR_RES_TEXT, &phrase);

  /* Quit early if an error occurred. */
  if (r != SNSR_RC_OK) return r;
  printf("Spotted \"%s\" at %.2f seconds.\n", phrase, begin/1000.0);

  /* Returning a code other than SNSR_RC_OK instructs snsrRun() to return it. */
  return SNSR_RC_STOP;
}


int
main(int argc, char *argv[])
{
  SnsrRC r;
  SnsrSession s;

  if (argc != 2) {
    fprintf(stderr, "usage: %s spotter-model\n", argv[0]);
    exit(1);
  }

  /* Create a new session handle. */
  snsrNew(&s);

  /* Load and validate the spotter model task file. */
  snsrLoad(s, snsrStreamFromFileName(argv[1], "r"));
  snsrRequire(s, SNSR_TASK_TYPE, SNSR_PHRASESPOT);

  /* Create a live audio stream instance and attach it to the session. */
  snsrSetStream(s, SNSR_SOURCE_AUDIO_PCM,
                snsrStreamFromAudioDevice(SNSR_ST_AF_DEFAULT));

  /* Register a result callback. Private data handle is not used */
  snsrSetHandler(s, SNSR_RESULT_EVENT, snsrCallback(resultEvent, NULL, NULL));

  /* Main recognition loop. The result handler will cause snsrRun() to
   * return SNSR_RC_STOP. Other return codes indicate an unexpected error.
   * Session errors remain until explicitly cleared: Any errors that occured
   * earlier will also be reported here.
   */
  r = snsrRun(s);
  if (r != SNSR_RC_STOP)
    fprintf(stderr, "ERROR: %s\n", snsrErrorDetail(s));

  /* Release the session. This will also release the model and audio streams,
   * and the callback handler. No other references to these handles are held,
   * so their memory will be reclaimed.
   */
  snsrRelease(s);
  return r;
}