adin_mic_linux_alsa.c

julius version 4.12.about sound recognition.

      return(FALSE);
    }
    if ((minsize = snd_pcm_hw_params_get_period_size_min(hwparams, &dir)) < 0) {
      jlog("Error: adin_alsa: cannot get minimum period size\n");
      return(FALSE);
    }
#else    
    has_current_period = TRUE;
    if ((err = snd_pcm_hw_params_get_period_time(hwparams, &period_time_current, &dir)) < 0) {
      has_current_period = FALSE;
    }
    if (has_current_period) {
      jlog("Stat: adin_alsa: current latency time: %d msec\n", period_time_current / 1000);
    }
#endif

    /* set period time (near value will be used) */
#if (SND_LIB_MAJOR == 0)
    periodsize = actual_rate * latency / 1000 * sizeof(SP16);
    if (periodsize < minsize) {
      jlog("Stat: adin_alsa: PCM latency of %d ms (%d bytes) too small, use device minimum %d bytes\n", latency, periodsize, minsize);
      periodsize = minsize;
    } else if (periodsize > maxsize) {
      jlog("Stat: adin_alsa: PCM latency of %d ms (%d bytes) too large, use device maximum %d bytes\n", latency, periodsize, maxsize);
      periodsize = maxsize;
    }
    actual_size = snd_pcm_hw_params_set_period_size_near(handle, hwparams, periodsize, &dir);
    if (actual_size < 0) {
      jlog("Error: adin_alsa: cannot set PCM record period size to %d (%s)\n", periodsize, snd_strerror(actual_size));
      return(FALSE);
    }
    if (actual_size != periodsize) {
      jlog("Stat: adin_alsa: PCM period size: %d bytes (%dms) -> %d bytes\n", periodsize, latency, actual_size);
    }
    jlog("Stat: Audio I/O Latency = %d msec (data fragment = %d frames)\n", actual_size * 1000 / (actual_rate * sizeof(SP16)), actual_size / sizeof(SP16));
#else
    period_time = latency * 1000;
    if (!force && has_current_period && period_time > period_time_current) {
	jlog("Stat: adin_alsa: current latency (%dms) is shorter than %dms, leave it\n", period_time_current / 1000, latency);
	period_time = period_time_current;
    } else {
      if ((err = snd_pcm_hw_params_set_period_time_near(handle, hwparams, &period_time, 0)) < 0) {
	jlog("Error: adin_alsa: cannot set PCM record period time to %d msec (%s)\n", period_time / 1000, snd_strerror(err));
	return(FALSE);
      }
      snd_pcm_hw_params_get_period_size(hwparams, &chunk_size, 0);
      jlog("Stat: adin_alsa: latency set to %d msec (chunk = %d bytes)\n", period_time / 1000, chunk_size);
    }
#endif

#if (SND_LIB_MAJOR == 0)
    /* set number of periods ( = 2) */
    if ((err = snd_pcm_hw_params_set_periods(handle, hwparams, sizeof(SP16), 0)) < 0) {
      jlog("Error: adin_alsa: cannot set PCM number of periods to %d (%s)\n", sizeof(SP16), snd_strerror(err));
      return(FALSE);
    }
#endif
  }

  /* apply the configuration to the PCM device */
  if ((err = snd_pcm_hw_params(handle, hwparams)) < 0) {
    jlog("Error: adin_alsa: cannot set PCM hardware parameters (%s)\n", snd_strerror(err));
    return(FALSE);
  }

  /* prepare for recording */
  if ((err = snd_pcm_prepare(handle)) < 0) {
    jlog("Error: adin_alsa: failed to prepare audio interface (%s)\n", snd_strerror(err));
  }

#if (SND_LIB_MAJOR == 0)
  /* prepare for polling */
  count = snd_pcm_poll_descriptors_count(handle);
  if (count <= 0) {
    jlog("Error: adin_alsa: invalid PCM poll descriptors count\n");
    return(FALSE);
  }
  ufds = mymalloc(sizeof(struct pollfd) * count);
  if ((err = snd_pcm_poll_descriptors(handle, ufds, count)) < 0) {
    jlog("Error: adin_alsa: unable to obtain poll descriptors for PCM recording (%s)\n", snd_strerror(err));
    return(FALSE);
  }
#endif

  /* output status */
  output_card_info(pcm_name, handle);

  return(TRUE);
#endif /* HAS_ALSA */
}

#ifdef HAS_ALSA
/** 
 * Error recovery when PCM buffer underrun or suspend.
 * 
 * @param handle [in] audio handler
 * @param err [in] error code
 * 
 * @return 0 on success, otherwise the given errno.
 */
static int
xrun_recovery(snd_pcm_t *handle, int err)
{
  if (err == -EPIPE) {    /* under-run */
    err = snd_pcm_prepare(handle);
    if (err < 0)
      jlog("Error: adin_alsa: can't recovery from PCM buffer underrun, prepare failed: %s\n", snd_strerror(err));
    return 0;
  } else if (err == -ESTRPIPE) {
    while ((err = snd_pcm_resume(handle)) == -EAGAIN)
      sleep(1);       /* wait until the suspend flag is released */
    if (err < 0) {
      err = snd_pcm_prepare(handle);
      if (err < 0)
	jlog("Error: adin_alsa: can't recovery from PCM buffer suspend, prepare failed: %s\n", snd_strerror(err));
    }
    return 0;
  }
  return err;
}
#endif /* HAS_ALSA */

/** 
 * Start recording.
 * 
 * @return TRUE on success, FALSE on failure.
 */
boolean
adin_alsa_begin()
{
#ifndef HAS_ALSA
  return FALSE;
#else
  int err;
  snd_pcm_state_t status;

  /* check hardware status */
  while(1) {			/* wait till prepared */
    status = snd_pcm_state(handle);
    switch(status) {
    case SND_PCM_STATE_PREPARED: /* prepared for operation */
      if ((err = snd_pcm_start(handle)) < 0) {
	jlog("Error: adin_alsa: cannot start PCM (%s)\n", snd_strerror(err));
	return (FALSE);
      }
      return(TRUE);
      break;
    case SND_PCM_STATE_RUNNING:	/* capturing the samples of other application */
      if ((err = snd_pcm_drop(handle)) < 0) { /* discard the existing samples */
	jlog("Error: adin_alsa: cannot drop PCM (%s)\n", snd_strerror(err));
	return (FALSE);
      }
      break;
    case SND_PCM_STATE_XRUN:	/* buffer overrun */
      if ((err = xrun_recovery(handle, -EPIPE)) < 0) {
	jlog("Error: adin_alsa: PCM XRUN recovery failed (%s)\n", snd_strerror(err));
	return(FALSE);
      }
      break;
    case SND_PCM_STATE_SUSPENDED:	/* suspended by power management system */
      if ((err = xrun_recovery(handle, -ESTRPIPE)) < 0) {
	jlog("Error: adin_alsa: PCM XRUN recovery failed (%s)\n", snd_strerror(err));
	return(FALSE);
      }
      break;
    default:
      /* do nothing */
      break;
    }
  }

  return(TRUE);
#endif /* HAS_ALSA */
}
  
/** 
 * Stop recording.
 * 
 * @return TRUE on success, FALSE on failure.
 */
boolean
adin_alsa_end()
{
  return(TRUE);
}

/**
 * @brief  Read samples from device
 * 
 * Try to read @a sampnum samples and returns actual number of recorded
 * samples currently available.  This function will block until
 * at least one sample can be obtained.
 * 
 * @param buf [out] samples obtained in this function
 * @param sampnum [in] wanted number of samples to be read
 * 
 * @return actural number of read samples, -2 if an error occured.
 */
int
adin_alsa_read(SP16 *buf, int sampnum)
{
#ifndef HAS_ALSA
  return -2;
#else
  int cnt;

#if (SND_LIB_MAJOR == 0)

  snd_pcm_sframes_t avail;

  while ((avail = snd_pcm_avail_update(handle)) <= 0) {
    usleep(latency * 1000);
  }
  if (avail < sampnum) {
    cnt = snd_pcm_readi(handle, buf, avail);
  } else {
    cnt = snd_pcm_readi(handle, buf, sampnum);
  }

#else

  int ret;
  snd_pcm_status_t *status;
  int res;
  struct timeval now, diff, tstamp;

  ret = snd_pcm_wait(handle, MAXPOLLINTERVAL);
  switch (ret) {
  case 0:			/* timeout */
    jlog("Warning: adin_alsa: no data fragment after %d msec?\n", MAXPOLLINTERVAL);
    cnt = 0;
    break;
  case 1:			/* has data */
    cnt = snd_pcm_readi(handle, buf, sampnum); /* read available (non-block) */
    break;
  case -EPIPE:			/* pipe error */
    /* try to recover the broken pipe */
    snd_pcm_status_alloca(&status);
    if ((res = snd_pcm_status(handle, status))<0) {
      jlog("Error: adin_alsa: broken pipe: status error (%s)\n", snd_strerror(res));
      return -2;
    }
    if (snd_pcm_status_get_state(status) == SND_PCM_STATE_XRUN) {
      gettimeofday(&now, 0);
      snd_pcm_status_get_trigger_tstamp(status, &tstamp);
      timersub(&now, &tstamp, &diff);
      jlog("Warning: adin_alsa: overrun!!! (at least %.3f ms long)\n",
	   diff.tv_sec * 1000 + diff.tv_usec / 1000.0);
      if ((res = snd_pcm_prepare(handle))<0) {
	jlog("Error: adin_alsa: overrun: prepare error (%s)", snd_strerror(res));
	return -2;
      }
      break;         /* ok, data should be accepted again */
    } else if (snd_pcm_status_get_state(status) == SND_PCM_STATE_DRAINING) {
      jlog("Warning: adin_alsa: draining: capture stream format change? attempting recover...\n");
      if ((res = snd_pcm_prepare(handle))<0) {
	jlog("Error: adin_alsa: draining: prepare error (%s)", snd_strerror(res));
	return -2;
      }
      break;
    }
    jlog("Error: adin_alsa: error in snd_pcm_wait() (%s)\n", snd_pcm_state_name(snd_pcm_status_get_state(status)));
    return -2;

  default:			/* other poll error */
    jlog("Error: adin_alsa: error in snd_pcm_wait() (%s)\n", snd_strerror(ret));
    return(-2);			/* error */
  }
#endif
  if (cnt < 0) {
    jlog("Error: adin_alsa: failed to read PCM (%s)\n", snd_strerror(cnt));
    return(-2);
  }
  if (need_swap) {
    swap_sample_bytes(buf, cnt);
  }

  return(cnt);
#endif /* HAS_ALSA */
}

/* end of file */