PARA_INFO_LOG("bytes per frame: %zu\n", pad->bytes_per_frame);
if (snd_pcm_nonblock(pad->handle, 1))
PARA_ERROR_LOG("failed to set nonblock mode\n");
PARA_INFO_LOG("bytes per frame: %zu\n", pad->bytes_per_frame);
if (snd_pcm_nonblock(pad->handle, 1))
PARA_ERROR_LOG("failed to set nonblock mode\n");