now the problem is that the sound is skipping.

Can you provide a recording of what it sounds like?

In alsa-lib there is an example test/latency.c which just moves samples from 
one device to another.

When I run it, the sound that comes out of my speakers is what I would call 

I submitted a bug report here, which has recordings of what I hear when I run 

It was closed by someone named Jaroslav Kysela who is the author of ALSA, 
according to Wikipedia. But I'm not sure if he read the actual bug report.

I don't know where you got the idea to call snd_pcm_prepare in your loop, or 
why that fixed the problem.

I hope this is helpful.


On Tue, Jun 23, 2020 at 04:54:09PM -0300, Sleep wrote:
Update, forgot snd_pcm_prepare(), now the problem is that the sound is skipping.

#include <stdlib.h>
#include <stdint.h>
#include <alsa/asoundlib.h>

#define STEREO 2
#define BITS 16 / 8
#define FRAMEBUFFERSIZE 512 // in samples
#define PERIODS 2
#define SAMPLERATE 11025

int main(void)
   snd_pcm_t *handle;
   uint32_t channels = STEREO;
   uint32_t sample_size = BITS; // 16 bit
   uint32_t frame_size = sample_size * channels;
   snd_pcm_uframes_t frames = FRAMEBUFFERSIZE;
   snd_pcm_uframes_t frames_per_period = frames / PERIODS;
   int dir = 0; // No idea what this does.
   snd_pcm_hw_params_t *params;
   int16_t framebuffer[FRAMEBUFFERSIZE * STEREO * BITS] = {0};
   FILE *wav;
   int size;
   int status;

snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0); // SND_PCM_NONBLOCK);
   snd_pcm_hw_params_any(handle, params);
   snd_pcm_hw_params_set_buffer_size(handle, params, frames);
snd_pcm_hw_params_set_period_size(handle, params, frames_per_period, dir);
   snd_pcm_hw_params_set_rate(handle, params, SAMPLERATE, dir);
snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
   snd_pcm_hw_params_set_channels(handle, params, STEREO);
   snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE);
   snd_pcm_hw_params(handle, params);

   // Insert samples to framebuffer.
   wav = fopen("pcm1611s.wav", "r");
   fseek(wav, 0L, SEEK_END);
   size = ftell(wav);
   fseek(wav, 0L, SEEK_SET);
   size /= sizeof(signed short);
   while (size > 0)
fread(framebuffer, sizeof(int16_t), FRAMEBUFFERSIZE * STEREO * BITS, wav);
       status = snd_pcm_writei(handle, framebuffer, frames);
       if (status == -EPIPE)

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