int setparams_bufsize(snd_pcm_t *handle,
		      snd_pcm_hw_params_t *params,
		      snd_pcm_hw_params_t *tparams,
		      snd_pcm_uframes_t bufsize,
		      const char *id)
{
	int err;
	snd_pcm_uframes_t periodsize;

	snd_pcm_hw_params_copy(params, tparams);
	periodsize = bufsize * 2;
	err = snd_pcm_hw_params_set_buffer_size_near(handle, params, &periodsize);
	if (err < 0) {
		printf("Unable to set buffer size %li for %s: %s\n", bufsize * 2, id, snd_strerror(err));
		return err;
	}
	if (period_size > 0)
		periodsize = period_size;
	else
		periodsize /= 2;
	err = snd_pcm_hw_params_set_period_size_near(handle, params, &periodsize, 0);
	if (err < 0) {
		printf("Unable to set period size %li for %s: %s\n", periodsize, id, snd_strerror(err));
		return err;
	}
	return 0;
}
Example #2
0
bool CAESinkALSA::InitializeHW(AEAudioFormat &format)
{
  snd_pcm_hw_params_t *hw_params;

  snd_pcm_hw_params_alloca(&hw_params);
  memset(hw_params, 0, snd_pcm_hw_params_sizeof());

  snd_pcm_hw_params_any(m_pcm, hw_params);
  snd_pcm_hw_params_set_access(m_pcm, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);

  unsigned int sampleRate   = format.m_sampleRate;
  unsigned int channelCount = format.m_channelLayout.Count();
  snd_pcm_hw_params_set_rate_near    (m_pcm, hw_params, &sampleRate, NULL);
  snd_pcm_hw_params_set_channels_near(m_pcm, hw_params, &channelCount);

  /* ensure we opened X channels or more */
  if (format.m_channelLayout.Count() > channelCount)
  {
    CLog::Log(LOGINFO, "CAESinkALSA::InitializeHW - Unable to open the required number of channels");
  }

  /* update the channelLayout to what we managed to open */
  format.m_channelLayout.Reset();
  for (unsigned int i = 0; i < channelCount; ++i)
    format.m_channelLayout += ALSAChannelMap[i];

  snd_pcm_format_t fmt = AEFormatToALSAFormat(format.m_dataFormat);
  if (fmt == SND_PCM_FORMAT_UNKNOWN)
  {
    /* if we dont support the requested format, fallback to float */
    format.m_dataFormat = AE_FMT_FLOAT;
    fmt                 = SND_PCM_FORMAT_FLOAT;
  }

  /* try the data format */
  if (snd_pcm_hw_params_set_format(m_pcm, hw_params, fmt) < 0)
  {
    /* if the chosen format is not supported, try each one in decending order */
    CLog::Log(LOGINFO, "CAESinkALSA::InitializeHW - Your hardware does not support %s, trying other formats", CAEUtil::DataFormatToStr(format.m_dataFormat));
    for (enum AEDataFormat i = AE_FMT_MAX; i > AE_FMT_INVALID; i = (enum AEDataFormat)((int)i - 1))
    {
      if (AE_IS_RAW(i) || i == AE_FMT_MAX)
        continue;

      if (m_passthrough && i != AE_FMT_S16BE && i != AE_FMT_S16LE)
	continue;

      fmt = AEFormatToALSAFormat(i);

      if (fmt == SND_PCM_FORMAT_UNKNOWN || snd_pcm_hw_params_set_format(m_pcm, hw_params, fmt) < 0)
      {
        fmt = SND_PCM_FORMAT_UNKNOWN;
        continue;
      }

      int fmtBits = CAEUtil::DataFormatToBits(i);
      int bits    = snd_pcm_hw_params_get_sbits(hw_params);
      if (bits != fmtBits)
      {
        /* if we opened in 32bit and only have 24bits, pack into 24 */
        if (fmtBits == 32 && bits == 24)
          i = AE_FMT_S24NE4;
        else
          continue;
      }

      /* record that the format fell back to X */
      format.m_dataFormat = i;
      CLog::Log(LOGINFO, "CAESinkALSA::InitializeHW - Using data format %s", CAEUtil::DataFormatToStr(format.m_dataFormat));
      break;
    }

    /* if we failed to find a valid output format */
    if (fmt == SND_PCM_FORMAT_UNKNOWN)
    {
      CLog::Log(LOGERROR, "CAESinkALSA::InitializeHW - Unable to find a suitable output format");
      return false;
    }
  }

  snd_pcm_uframes_t periodSize, bufferSize;
  snd_pcm_hw_params_get_buffer_size_max(hw_params, &bufferSize);
  snd_pcm_hw_params_get_period_size_max(hw_params, &periodSize, NULL);

  /* 
   We want to make sure, that we have max 200 ms Buffer with 
   a periodSize of approx 50 ms. Choosing a higher bufferSize
   will cause problems with menu sounds. Buffer will be increased
   after those are fixed.
  */
  periodSize  = std::min(periodSize, (snd_pcm_uframes_t) sampleRate / 20);
  bufferSize  = std::min(bufferSize, (snd_pcm_uframes_t) sampleRate / 5);
  
  /* 
   According to upstream we should set buffer size first - so make sure it is always at least
   4x period size to not get underruns (some systems seem to have issues with only 2 periods)
  */
  periodSize = std::min(periodSize, bufferSize / 4);

  CLog::Log(LOGDEBUG, "CAESinkALSA::InitializeHW - Request: periodSize %lu, bufferSize %lu", periodSize, bufferSize);

  snd_pcm_hw_params_t *hw_params_copy;
  snd_pcm_hw_params_alloca(&hw_params_copy);
  snd_pcm_hw_params_copy(hw_params_copy, hw_params); // copy what we have and is already working

  // Make sure to not initialize too large to not cause underruns
  snd_pcm_uframes_t periodSizeMax = bufferSize / 3;
  if(snd_pcm_hw_params_set_period_size_max(m_pcm, hw_params_copy, &periodSizeMax, NULL) != 0)
  {
    snd_pcm_hw_params_copy(hw_params_copy, hw_params); // restore working copy
    CLog::Log(LOGDEBUG, "CAESinkALSA::InitializeHW - Request: Failed to limit periodSize to %lu", periodSizeMax);
  }
  
  // first trying bufferSize, PeriodSize
  // for more info see here:
  // http://mailman.alsa-project.org/pipermail/alsa-devel/2009-September/021069.html
  // the last three tries are done as within pulseaudio

  // backup periodSize and bufferSize first. Restore them after every failed try
  snd_pcm_uframes_t periodSizeTemp, bufferSizeTemp;
  periodSizeTemp = periodSize;
  bufferSizeTemp = bufferSize;
  if (snd_pcm_hw_params_set_buffer_size_near(m_pcm, hw_params_copy, &bufferSize) != 0
    || snd_pcm_hw_params_set_period_size_near(m_pcm, hw_params_copy, &periodSize, NULL) != 0
    || snd_pcm_hw_params(m_pcm, hw_params_copy) != 0)
  {
    bufferSize = bufferSizeTemp;
    periodSize = periodSizeTemp;
    // retry with PeriodSize, bufferSize
    snd_pcm_hw_params_copy(hw_params_copy, hw_params); // restore working copy
    if (snd_pcm_hw_params_set_period_size_near(m_pcm, hw_params_copy, &periodSize, NULL) != 0
      || snd_pcm_hw_params_set_buffer_size_near(m_pcm, hw_params_copy, &bufferSize) != 0
      || snd_pcm_hw_params(m_pcm, hw_params_copy) != 0)
    {
      // try only periodSize
      periodSize = periodSizeTemp;
      snd_pcm_hw_params_copy(hw_params_copy, hw_params); // restore working copy
      if(snd_pcm_hw_params_set_period_size_near(m_pcm, hw_params_copy, &periodSize, NULL) != 0 
        || snd_pcm_hw_params(m_pcm, hw_params_copy) != 0)
      {
        // try only BufferSize
        bufferSize = bufferSizeTemp;
        snd_pcm_hw_params_copy(hw_params_copy, hw_params); // restory working copy
        if (snd_pcm_hw_params_set_buffer_size_near(m_pcm, hw_params_copy, &bufferSize) != 0
          || snd_pcm_hw_params(m_pcm, hw_params_copy) != 0)
        {
          // set default that Alsa would choose
          CLog::Log(LOGWARNING, "CAESinkAlsa::IntializeHW - Using default alsa values - set failed");
          if (snd_pcm_hw_params(m_pcm, hw_params) != 0)
          {
            CLog::Log(LOGDEBUG, "CAESinkALSA::InitializeHW - Could not init a valid sink");
            return false;
          }
        }
      }
      // reread values when alsa default was kept
      snd_pcm_get_params(m_pcm, &bufferSize, &periodSize);
    }
  }
  
  CLog::Log(LOGDEBUG, "CAESinkALSA::InitializeHW - Got: periodSize %lu, bufferSize %lu", periodSize, bufferSize);

  /* set the format parameters */
  format.m_sampleRate   = sampleRate;
  format.m_frames       = periodSize;
  format.m_frameSamples = periodSize * format.m_channelLayout.Count();
  format.m_frameSize    = snd_pcm_frames_to_bytes(m_pcm, 1);

  m_bufferSize = (unsigned int)bufferSize;
  m_timeout    = std::ceil((double)(bufferSize * 1000) / (double)sampleRate);

  CLog::Log(LOGDEBUG, "CAESinkALSA::InitializeHW - Setting timeout to %d ms", m_timeout);

  return true;
}
Example #3
0
bool CAESinkALSA::InitializeHW(AEAudioFormat &format)
{
  snd_pcm_hw_params_t *hw_params;

  snd_pcm_hw_params_alloca(&hw_params);
  memset(hw_params, 0, snd_pcm_hw_params_sizeof());

  snd_pcm_hw_params_any(m_pcm, hw_params);
  snd_pcm_hw_params_set_access(m_pcm, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);

  unsigned int sampleRate   = format.m_sampleRate;
  unsigned int channelCount = format.m_channelLayout.Count();
  snd_pcm_hw_params_set_rate_near    (m_pcm, hw_params, &sampleRate, NULL);
  snd_pcm_hw_params_set_channels_near(m_pcm, hw_params, &channelCount);

  /* ensure we opened X channels or more */
  if (format.m_channelLayout.Count() > channelCount)
  {
    CLog::Log(LOGERROR, "CAESinkALSA::InitializeHW - Unable to open the required number of channels");
    return false;
  }

  /* update the channelLayout to what we managed to open */
  format.m_channelLayout.Reset();
  for (unsigned int i = 0; i < channelCount; ++i)
    format.m_channelLayout += ALSAChannelMap[i];

  snd_pcm_format_t fmt = AEFormatToALSAFormat(format.m_dataFormat);
  if (fmt == SND_PCM_FORMAT_UNKNOWN)
  {
    /* if we dont support the requested format, fallback to float */
    format.m_dataFormat = AE_FMT_FLOAT;
    fmt                 = SND_PCM_FORMAT_FLOAT;
  }

  /* try the data format */
  if (snd_pcm_hw_params_set_format(m_pcm, hw_params, fmt) < 0)
  {
    /* if the chosen format is not supported, try each one in decending order */
    CLog::Log(LOGINFO, "CAESinkALSA::InitializeHW - Your hardware does not support %s, trying other formats", CAEUtil::DataFormatToStr(format.m_dataFormat));
    for (enum AEDataFormat i = AE_FMT_MAX; i > AE_FMT_INVALID; i = (enum AEDataFormat)((int)i - 1))
    {
      if (AE_IS_RAW(i) || i == AE_FMT_MAX)
        continue;

      if (m_passthrough && i != AE_FMT_S16BE && i != AE_FMT_S16LE)
	continue;

      fmt = AEFormatToALSAFormat(i);

      if (fmt == SND_PCM_FORMAT_UNKNOWN || snd_pcm_hw_params_set_format(m_pcm, hw_params, fmt) < 0)
      {
        fmt = SND_PCM_FORMAT_UNKNOWN;
        continue;
      }

      int fmtBits = CAEUtil::DataFormatToBits(i);
      int bits    = snd_pcm_hw_params_get_sbits(hw_params);
      if (bits != fmtBits)
      {
        /* if we opened in 32bit and only have 24bits, pack into 24 */
        if (fmtBits == 32 && bits == 24)
          i = AE_FMT_S24NE4;
        else
          continue;
      }

      /* record that the format fell back to X */
      format.m_dataFormat = i;
      CLog::Log(LOGINFO, "CAESinkALSA::InitializeHW - Using data format %s", CAEUtil::DataFormatToStr(format.m_dataFormat));
      break;
    }

    /* if we failed to find a valid output format */
    if (fmt == SND_PCM_FORMAT_UNKNOWN)
    {
      CLog::Log(LOGERROR, "CAESinkALSA::InitializeHW - Unable to find a suitable output format");
      return false;
    }
  }

  unsigned int periods;

  snd_pcm_uframes_t periodSize, bufferSize;
  snd_pcm_hw_params_get_buffer_size_max(hw_params, &bufferSize);

  bufferSize  = std::min(bufferSize, (snd_pcm_uframes_t)8192);
  periodSize  = bufferSize / ALSA_PERIODS;
  periods     = ALSA_PERIODS;

  CLog::Log(LOGDEBUG, "CAESinkALSA::InitializeHW - Request: periodSize %lu, periods %u, bufferSize %lu", periodSize, periods, bufferSize);

  /* work on a copy of the hw params */
  snd_pcm_hw_params_t *hw_params_copy;
  snd_pcm_hw_params_alloca(&hw_params_copy);

  /* try to set the buffer size then the period size */
  snd_pcm_hw_params_copy(hw_params_copy, hw_params);
  snd_pcm_hw_params_set_buffer_size_near(m_pcm, hw_params_copy, &bufferSize);
  snd_pcm_hw_params_set_period_size_near(m_pcm, hw_params_copy, &periodSize, NULL);
  snd_pcm_hw_params_set_periods_near    (m_pcm, hw_params_copy, &periods   , NULL);
  if (snd_pcm_hw_params(m_pcm, hw_params_copy) != 0)
  {
    /* try to set the period size then the buffer size */
    snd_pcm_hw_params_copy(hw_params_copy, hw_params);
    snd_pcm_hw_params_set_period_size_near(m_pcm, hw_params_copy, &periodSize, NULL);
    snd_pcm_hw_params_set_buffer_size_near(m_pcm, hw_params_copy, &bufferSize);
    snd_pcm_hw_params_set_periods_near    (m_pcm, hw_params_copy, &periods   , NULL);
    if (snd_pcm_hw_params(m_pcm, hw_params_copy) != 0)
    {
      /* try to just set the buffer size */
      snd_pcm_hw_params_copy(hw_params_copy, hw_params);
      snd_pcm_hw_params_set_buffer_size_near(m_pcm, hw_params_copy, &bufferSize);
      snd_pcm_hw_params_set_periods_near    (m_pcm, hw_params_copy, &periods   , NULL);
      if (snd_pcm_hw_params(m_pcm, hw_params_copy) != 0)
      {
        /* try to just set the period size */
        snd_pcm_hw_params_copy(hw_params_copy, hw_params);
        snd_pcm_hw_params_set_period_size_near(m_pcm, hw_params_copy, &periodSize, NULL);
        snd_pcm_hw_params_set_periods_near    (m_pcm, hw_params_copy, &periods   , NULL);
        if (snd_pcm_hw_params(m_pcm, hw_params_copy) != 0)
        {
          CLog::Log(LOGERROR, "CAESinkALSA::InitializeHW - Failed to set the parameters");
          return false;
        }
      }
    }
  }

  snd_pcm_hw_params_get_period_size(hw_params_copy, &periodSize, NULL);
  snd_pcm_hw_params_get_buffer_size(hw_params_copy, &bufferSize);
  

  CLog::Log(LOGDEBUG, "CAESinkALSA::InitializeHW - Got: periodSize %lu, periods %u, bufferSize %lu", periodSize, periods, bufferSize);

  /* set the format parameters */
  format.m_sampleRate   = sampleRate;
  format.m_frames       = periodSize;
  format.m_frameSamples = periodSize * format.m_channelLayout.Count();
  format.m_frameSize    = snd_pcm_frames_to_bytes(m_pcm, 1);

  m_bufferSize = (unsigned int)bufferSize;
  m_timeout    = std::ceil((double)(bufferSize * 1000) / (double)sampleRate);

  CLog::Log(LOGDEBUG, "CAESinkALSA::InitializeHW - Setting timeout to %d ms", m_timeout);

  return true;
}
Example #4
0
/**************************************************************************
 * 				widOpen				[internal]
 */
static DWORD widOpen(WORD wDevID, LPWAVEOPENDESC lpDesc, DWORD dwFlags)
{
    WINE_WAVEDEV*	        wwi;
    snd_pcm_hw_params_t *       hw_params;
    snd_pcm_sw_params_t *       sw_params;
    snd_pcm_access_t            access;
    snd_pcm_format_t            format;
    unsigned int                rate;
    unsigned int                buffer_time = 500000;
    unsigned int                period_time = 10000;
    snd_pcm_uframes_t           buffer_size;
    snd_pcm_uframes_t           period_size;
    int                         flags;
    snd_pcm_t *                 pcm;
    int                         err;
    int                         dir;
    DWORD                       ret;

    /* JPW TODO - review this code */
    TRACE("(%u, %p, %08X);\n", wDevID, lpDesc, dwFlags);
    if (lpDesc == NULL) {
	WARN("Invalid Parameter !\n");
	return MMSYSERR_INVALPARAM;
    }
    if (wDevID >= ALSA_WidNumDevs) {
	TRACE("Requested device %d, but only %d are known!\n", wDevID, ALSA_WidNumDevs);
	return MMSYSERR_BADDEVICEID;
    }

    /* only PCM format is supported so far... */
    if (!ALSA_supportedFormat(lpDesc->lpFormat)) {
	WARN("Bad format: tag=%04X nChannels=%d nSamplesPerSec=%d !\n",
	     lpDesc->lpFormat->wFormatTag, lpDesc->lpFormat->nChannels,
	     lpDesc->lpFormat->nSamplesPerSec);
	return WAVERR_BADFORMAT;
    }

    if (dwFlags & WAVE_FORMAT_QUERY) {
	TRACE("Query format: tag=%04X nChannels=%d nSamplesPerSec=%d !\n",
	     lpDesc->lpFormat->wFormatTag, lpDesc->lpFormat->nChannels,
	     lpDesc->lpFormat->nSamplesPerSec);
	return MMSYSERR_NOERROR;
    }

    wwi = &WInDev[wDevID];

    if (wwi->pcm != NULL) {
        WARN("already allocated\n");
        return MMSYSERR_ALLOCATED;
    }

    wwi->pcm = 0;
    flags = SND_PCM_NONBLOCK;

    if ( (err=snd_pcm_open(&pcm, wwi->pcmname, SND_PCM_STREAM_CAPTURE, flags)) < 0 )
    {
        ERR("Error open: %s\n", snd_strerror(err));
	return MMSYSERR_NOTENABLED;
    }

    wwi->wFlags = HIWORD(dwFlags & CALLBACK_TYPEMASK);

    wwi->waveDesc = *lpDesc;
    ALSA_copyFormat(lpDesc->lpFormat, &wwi->format);

    if (wwi->format.Format.wBitsPerSample == 0) {
	WARN("Resetting zeroed wBitsPerSample\n");
	wwi->format.Format.wBitsPerSample = 8 *
	    (wwi->format.Format.nAvgBytesPerSec /
	     wwi->format.Format.nSamplesPerSec) /
	    wwi->format.Format.nChannels;
    }

    hw_params = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, snd_pcm_hw_params_sizeof() );
    sw_params = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, snd_pcm_sw_params_sizeof() );

    snd_pcm_hw_params_any(pcm, hw_params);

#define EXIT_ON_ERROR(f,e,txt) do \
{ \
    int err; \
    if ( (err = (f) ) < 0) \
    { \
	WARN(txt ": %s\n", snd_strerror(err)); \
	ret = (e); \
        goto error; \
    } \
} while(0)

    access = SND_PCM_ACCESS_MMAP_INTERLEAVED;
    if ( ( err = snd_pcm_hw_params_set_access(pcm, hw_params, access ) ) < 0) {
        WARN("mmap not available. switching to standard write.\n");
        access = SND_PCM_ACCESS_RW_INTERLEAVED;
	EXIT_ON_ERROR( snd_pcm_hw_params_set_access(pcm, hw_params, access ), MMSYSERR_INVALPARAM, "unable to set access for playback");
	wwi->read = snd_pcm_readi;
    }
    else
	wwi->read = snd_pcm_mmap_readi;

    EXIT_ON_ERROR( snd_pcm_hw_params_set_channels(pcm, hw_params, wwi->format.Format.nChannels), WAVERR_BADFORMAT, "unable to set required channels");

    if ((wwi->format.Format.wFormatTag == WAVE_FORMAT_PCM) ||
        ((wwi->format.Format.wFormatTag == WAVE_FORMAT_EXTENSIBLE) &&
        IsEqualGUID(&wwi->format.SubFormat, &KSDATAFORMAT_SUBTYPE_PCM))) {
        format = (wwi->format.Format.wBitsPerSample == 8) ? SND_PCM_FORMAT_U8 :
                 (wwi->format.Format.wBitsPerSample == 16) ? SND_PCM_FORMAT_S16_LE :
                 (wwi->format.Format.wBitsPerSample == 24) ? SND_PCM_FORMAT_S24_3LE :
                 (wwi->format.Format.wBitsPerSample == 32) ? SND_PCM_FORMAT_S32_LE : -1;
    } else if ((wwi->format.Format.wFormatTag == WAVE_FORMAT_EXTENSIBLE) &&
        IsEqualGUID(&wwi->format.SubFormat, &KSDATAFORMAT_SUBTYPE_IEEE_FLOAT)){
        format = (wwi->format.Format.wBitsPerSample == 32) ? SND_PCM_FORMAT_FLOAT_LE : -1;
    } else if (wwi->format.Format.wFormatTag == WAVE_FORMAT_MULAW) {
        FIXME("unimplemented format: WAVE_FORMAT_MULAW\n");
        ret = WAVERR_BADFORMAT;
        goto error;
    } else if (wwi->format.Format.wFormatTag == WAVE_FORMAT_ALAW) {
        FIXME("unimplemented format: WAVE_FORMAT_ALAW\n");
        ret = WAVERR_BADFORMAT;
        goto error;
    } else if (wwi->format.Format.wFormatTag == WAVE_FORMAT_ADPCM) {
        FIXME("unimplemented format: WAVE_FORMAT_ADPCM\n");
        ret = WAVERR_BADFORMAT;
        goto error;
    } else {
        ERR("invalid format: %0x04x\n", wwi->format.Format.wFormatTag);
        ret = WAVERR_BADFORMAT;
        goto error;
    }

    EXIT_ON_ERROR( snd_pcm_hw_params_set_format(pcm, hw_params, format), WAVERR_BADFORMAT, "unable to set required format");

    rate = wwi->format.Format.nSamplesPerSec;
    dir = 0;
    err = snd_pcm_hw_params_set_rate_near(pcm, hw_params, &rate, &dir);
    if (err < 0) {
	WARN("Rate %d Hz not available for playback: %s\n", wwi->format.Format.nSamplesPerSec, snd_strerror(rate));
        ret = WAVERR_BADFORMAT;
        goto error;
    }
    if (!ALSA_NearMatch(rate, wwi->format.Format.nSamplesPerSec)) {
	WARN("Rate doesn't match (requested %d Hz, got %d Hz)\n", wwi->format.Format.nSamplesPerSec, rate);
        ret = WAVERR_BADFORMAT;
        goto error;
    }

    dir=0;
    EXIT_ON_ERROR( snd_pcm_hw_params_set_buffer_time_near(pcm, hw_params, &buffer_time, &dir), MMSYSERR_INVALPARAM, "unable to set buffer time");
    dir=0;
    EXIT_ON_ERROR( snd_pcm_hw_params_set_period_time_near(pcm, hw_params, &period_time, &dir), MMSYSERR_INVALPARAM, "unable to set period time");

    EXIT_ON_ERROR( snd_pcm_hw_params(pcm, hw_params), MMSYSERR_INVALPARAM, "unable to set hw params for playback");

    dir=0;
    err = snd_pcm_hw_params_get_period_size(hw_params, &period_size, &dir);
    err = snd_pcm_hw_params_get_buffer_size(hw_params, &buffer_size);

    snd_pcm_sw_params_current(pcm, sw_params);
    EXIT_ON_ERROR( snd_pcm_sw_params_set_start_threshold(pcm, sw_params, 1), MMSYSERR_ERROR, "unable to set start threshold");
    EXIT_ON_ERROR( snd_pcm_sw_params_set_silence_size(pcm, sw_params, 0), MMSYSERR_ERROR, "unable to set silence size");
    EXIT_ON_ERROR( snd_pcm_sw_params_set_avail_min(pcm, sw_params, period_size), MMSYSERR_ERROR, "unable to set avail min");
    EXIT_ON_ERROR( snd_pcm_sw_params_set_silence_threshold(pcm, sw_params, 0), MMSYSERR_ERROR, "unable to set silence threshold");
    EXIT_ON_ERROR( snd_pcm_sw_params(pcm, sw_params), MMSYSERR_ERROR, "unable to set sw params for playback");
#undef EXIT_ON_ERROR

    snd_pcm_prepare(pcm);

    if (TRACE_ON(wave))
	ALSA_TraceParameters(hw_params, sw_params, FALSE);

    /* now, we can save all required data for later use... */
    if ( wwi->hw_params )
	snd_pcm_hw_params_free(wwi->hw_params);
    snd_pcm_hw_params_malloc(&(wwi->hw_params));
    snd_pcm_hw_params_copy(wwi->hw_params, hw_params);

    wwi->dwBufferSize = snd_pcm_frames_to_bytes(pcm, buffer_size);
    wwi->lpQueuePtr = wwi->lpPlayPtr = wwi->lpLoopPtr = NULL;
    wwi->pcm = pcm;

    ALSA_InitRingMessage(&wwi->msgRing);

    wwi->dwPeriodSize = snd_pcm_frames_to_bytes(pcm, period_size);
    TRACE("dwPeriodSize=%u\n", wwi->dwPeriodSize);
    TRACE("wBitsPerSample=%u, nAvgBytesPerSec=%u, nSamplesPerSec=%u, nChannels=%u nBlockAlign=%u!\n",
	  wwi->format.Format.wBitsPerSample, wwi->format.Format.nAvgBytesPerSec,
	  wwi->format.Format.nSamplesPerSec, wwi->format.Format.nChannels,
	  wwi->format.Format.nBlockAlign);

    wwi->hStartUpEvent = CreateEventW(NULL, FALSE, FALSE, NULL);
    wwi->hThread = CreateThread(NULL, 0, widRecorder, (LPVOID)(DWORD_PTR)wDevID, 0, &(wwi->dwThreadID));
    if (wwi->hThread)
        SetThreadPriority(wwi->hThread, THREAD_PRIORITY_TIME_CRITICAL);
    WaitForSingleObject(wwi->hStartUpEvent, INFINITE);
    CloseHandle(wwi->hStartUpEvent);
    wwi->hStartUpEvent = INVALID_HANDLE_VALUE;

    HeapFree( GetProcessHeap(), 0, hw_params );
    HeapFree( GetProcessHeap(), 0, sw_params );
    return widNotifyClient(wwi, WIM_OPEN, 0L, 0L);

error:
    snd_pcm_close(pcm);
    HeapFree( GetProcessHeap(), 0, hw_params );
    HeapFree( GetProcessHeap(), 0, sw_params );
    return ret;
}