public static extern int snd_pcm_playback_format(IntPtr playback_handle, ref snd_pcm_format format);
internal static extern int snd_pcm_hw_params_set_format(IntPtr playback_handle, IntPtr hw_params, snd_pcm_format snd_pcm_format);
public static extern int snd_pcm_hw_params_set_format(IntPtr playback_handle,IntPtr hw_params,snd_pcm_format snd_pcm_format);
internal static extern int snd_pcm_playback_format(IntPtr playback_handle, ref snd_pcm_format format);