コード例 #1
0
ファイル: alsa.go プロジェクト: charneykaye/goalsa
// Close closes a device and frees the resources associated with it.
func (d *device) Close() {
	if d.h != nil {
		C.snd_pcm_drain(d.h)
		C.snd_pcm_close(d.h)
		d.h = nil
	}
	runtime.SetFinalizer(d, nil)
}
コード例 #2
0
ファイル: alsa.go プロジェクト: terual/alsa-go
// Drain stream. For playback wait for all pending frames to be played and
// then stop the PCM. For capture stop PCM permitting to retrieve residual frames.
func (handle *Handle) Drain() error {

	err := C.snd_pcm_drain(handle.cHandle)
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot drain stream. %s",
			strError(err)))
	}
	return nil

}
コード例 #3
0
ファイル: alsa.go プロジェクト: wendal/alsa-go
// ApplyHwParams changes ALSA hardware parameters for the current stream.
func (handle *Handle) ApplyHwParams() error {
	var cHwParams *C.snd_pcm_hw_params_t

	err := C.snd_pcm_hw_params_malloc(&cHwParams)
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot allocate hardware parameter structure. %s",
			strError(err)))
	}

	err = C.snd_pcm_hw_params_any(handle.cHandle, cHwParams)
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot initialize hardware parameter structure. %s",
			strError(err)))
	}

	err = C.snd_pcm_hw_params_set_access(handle.cHandle, cHwParams, C.SND_PCM_ACCESS_RW_INTERLEAVED)
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot set access type. %s",
			strError(err)))
	}

	err = C.snd_pcm_hw_params_set_format(handle.cHandle, cHwParams, _Ctype_snd_pcm_format_t(handle.SampleFormat))
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot set sample format. %s",
			strError(err)))
	}

	var cSampleRate _Ctype_uint = _Ctype_uint(handle.SampleRate)
	err = C.snd_pcm_hw_params_set_rate_near(handle.cHandle, cHwParams, &cSampleRate, nil)
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot set sample rate. %s",
			strError(err)))
	}

	err = C.snd_pcm_hw_params_set_channels(handle.cHandle, cHwParams, _Ctype_uint(handle.Channels))
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot set number of channels. %s",
			strError(err)))
	}

	// Drain current data and make sure we aren't underrun.
	C.snd_pcm_drain(handle.cHandle)

	err = C.snd_pcm_hw_params(handle.cHandle, cHwParams)
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot set hardware parameters. %s",
			strError(err)))
	}

	C.snd_pcm_hw_params_free(cHwParams)

	return nil
}
コード例 #4
0
ファイル: alsa.go プロジェクト: terual/alsa-go
// ApplyHwParams changes ALSA hardware parameters for the current stream.
func (handle *Handle) ApplyHwParams() error {
	var cHwParams *C.snd_pcm_hw_params_t

	err := C.snd_pcm_hw_params_malloc(&cHwParams)
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot allocate hardware parameter structure. %s",
			strError(err)))
	}

	err = C.snd_pcm_hw_params_any(handle.cHandle, cHwParams)
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot initialize hardware parameter structure. %s",
			strError(err)))
	}

	err = C.snd_pcm_hw_params_set_access(handle.cHandle, cHwParams, C.SND_PCM_ACCESS_RW_INTERLEAVED)
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot set access type. %s",
			strError(err)))
	}

	err = C.snd_pcm_hw_params_set_format(handle.cHandle, cHwParams, C.snd_pcm_format_t(handle.SampleFormat))
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot set sample format. %s",
			strError(err)))
	}

	var cSampleRate _Ctype_uint = _Ctype_uint(handle.SampleRate)
	err = C.snd_pcm_hw_params_set_rate_near(handle.cHandle, cHwParams, &cSampleRate, nil)
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot set sample rate. %s",
			strError(err)))
	}

	err = C.snd_pcm_hw_params_set_channels(handle.cHandle, cHwParams, _Ctype_uint(handle.Channels))
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot set number of channels. %s",
			strError(err)))
	}

	if handle.Periods > 0 {
		// Set number of periods. Periods used to be called fragments.
		/*err = C.snd_pcm_hw_params_set_periods(handle.cHandle, cHwParams, _Ctype_uint(handle.Periods), 0)
		if err < 0 {
			return os.NewError(fmt.Sprintf("Cannot set number of periods. %s",
				strError(err)))
		}*/

		var cPeriods _Ctype_uint = _Ctype_uint(handle.Periods)
		var cDir _Ctype_int = 0 // Exact value is <,=,> the returned one following dir (-1,0,1)
		err = C.snd_pcm_hw_params_set_periods_near(handle.cHandle, cHwParams, &cPeriods, &cDir)
		if err < 0 {
			return errors.New(fmt.Sprintf("Cannot set number of periods. %s",
				strError(err)))
		}
	}

	if handle.Buffersize > 0 {
		// Set buffer size (in frames). The resulting latency is given by
		// latency = periodsize * periods / (rate * bytes_per_frame)
		/*err = C.snd_pcm_hw_params_set_buffer_size(handle.cHandle, cHwParams, _Ctypedef_snd_pcm_uframes_t(handle.Buffersize))
		if err < 0 {
			return os.NewError(fmt.Sprintf("Cannot set buffersize. %s",
				strError(err)))
		}*/

		var cBuffersize C.snd_pcm_uframes_t = C.snd_pcm_uframes_t(handle.Buffersize)
		err = C.snd_pcm_hw_params_set_buffer_size_near(handle.cHandle, cHwParams, &cBuffersize)
		if err < 0 {
			return errors.New(fmt.Sprintf("Cannot set buffersize. %s",
				strError(err)))
		}

	}

	// Drain current data and make sure we aren't underrun.
	C.snd_pcm_drain(handle.cHandle)

	err = C.snd_pcm_hw_params(handle.cHandle, cHwParams)
	if err < 0 {
		return errors.New(fmt.Sprintf("Cannot set hardware parameters. %s",
			strError(err)))
	}

	C.snd_pcm_hw_params_free(cHwParams)

	return nil
}