Hello again. I'm using alsa-kernel. My configuration: SNDRV_PCM_HW_PARAM_ACCESS = SNDRV_PCM_ACCESS_RW_INTERLEAVED SNDRV_PCM_HW_PARAM_FORMAT = SNDRV_PCM_FORMAT_S16_LE SNDRV_PCM_HW_PARAM_SUBFORMAT = SNDRV_PCM_SUBFORMAT_STD SNDRV_PCM_HW_PARAM_CHANNELS = 2 SNDRV_PCM_HW_PARAM_RATE = 48000
I have a vsynced game loop that is running at 60fps:
int num_base_samples = 48000 * (1 / 60); int num_samples = num_base_samples * 2; int16_t buffer[num_samples] = {};
while (true) { int16_t *samples = buffer; for (int sample_i = 0; sample_i < num_base_samples; sample_i++) { *samples++ = 0x33; *samples++ = 0x33; }
struct snd_xferi transfer = {}; transfer.buf = buffer; transfer.frames = num_base_samples; ioctl(fd, SNDRV_PCM_IOCTL_WRITEI_FRAMES, &transfer);
// ioctl(fd, SNDRV_PCM_IOCTL_DRAIN); --> NECESSARY??? // ioctl(fd, SNDRV_PCM_IOCTL_PREPARE); --> NECESSARY??? }
On the first iteration of SNDRV_PCM_IOCTL_WRITEI_FRAMES I get no error. All subsequent iterations, I get Broken Pipe error. So, to counteract this at the end of each frame I call SNDRV_PCM_IOCTL_DRAIN and SNDRV_PCM_IOCTL_PREPARE. This removes the Broken Pipe error however slows the program down by half and no sound is heard. How best to solve this issue?
Thanks again -- Ryan McClue, Sydney