luboslenco
106 lines
3.0 KiB
C
106 lines
3.0 KiB
C
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#ifdef IRON_AUDIO
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#include <alsa/asoundlib.h>
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#include <iron_audio.h>
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#include <pthread.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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iron_a2_buffer_t a2_buffer;
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pthread_t threadid;
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bool audio_running = false;
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snd_pcm_t *playback_handle;
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static unsigned int samples_per_second = 44100;
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static bool initialized = false;
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static snd_pcm_uframes_t period_size = 2048;
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static short buf[4096];
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uint32_t iron_a2_samples_per_second(void) {
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return samples_per_second;
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}
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static void copy_sample(void *buffer) {
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float left_value = a2_buffer.channels[0][a2_buffer.read_location];
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float right_value = a2_buffer.channels[1][a2_buffer.read_location];
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a2_buffer.read_location += 1;
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if (a2_buffer.read_location >= a2_buffer.data_size) {
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a2_buffer.read_location = 0;
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}
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((int16_t *)buffer)[0] = (int16_t)(left_value * 32767);
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((int16_t *)buffer)[1] = (int16_t)(right_value * 32767);
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}
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void *audio_thread(void *arg) {
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if (snd_pcm_open(&playback_handle, "default", SND_PCM_STREAM_PLAYBACK, 0) < 0) {
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fprintf(stderr, "Error: cannot open audio device\n");
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return NULL;
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}
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int dir = 0;
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snd_pcm_hw_params_t *hw_params;
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snd_pcm_hw_params_malloc(&hw_params);
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snd_pcm_hw_params_any(playback_handle, hw_params);
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snd_pcm_hw_params_set_access(playback_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
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snd_pcm_hw_params_set_format(playback_handle, hw_params, SND_PCM_FORMAT_S16_LE);
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snd_pcm_hw_params_set_rate_near(playback_handle, hw_params, &samples_per_second, &dir);
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snd_pcm_hw_params_set_channels(playback_handle, hw_params, 2);
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snd_pcm_hw_params_set_period_size_near(playback_handle, hw_params, &period_size, &dir);
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snd_pcm_uframes_t buffer_size = period_size * 4;
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snd_pcm_hw_params_set_buffer_size_near(playback_handle, hw_params, &buffer_size);
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snd_pcm_hw_params(playback_handle, hw_params);
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snd_pcm_hw_params_get_period_size(hw_params, &period_size, &dir);
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snd_pcm_hw_params_free(hw_params);
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snd_pcm_prepare(playback_handle);
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while (audio_running) {
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if (iron_a2_internal_callback(&a2_buffer, (int)period_size)) {
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for (int i = 0; i < (int)period_size; i++) {
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copy_sample(&buf[i * 2]);
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}
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}
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else {
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memset(buf, 0, period_size * 2 * sizeof(short));
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}
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snd_pcm_sframes_t written;
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while ((written = snd_pcm_writei(playback_handle, buf, period_size)) < 0) {
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written = snd_pcm_recover(playback_handle, (int)written, 0);
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if (written < 0) {
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goto done;
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}
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}
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}
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done:
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snd_pcm_close(playback_handle);
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return NULL;
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}
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void iron_a2_init() {
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if (initialized) {
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return;
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}
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iron_a2_internal_init();
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initialized = true;
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a2_buffer.read_location = 0;
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a2_buffer.write_location = 0;
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a2_buffer.data_size = 128 * 1024;
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a2_buffer.channel_count = 2;
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a2_buffer.channels[0] = (float *)malloc(a2_buffer.data_size * sizeof(float));
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a2_buffer.channels[1] = (float *)malloc(a2_buffer.data_size * sizeof(float));
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audio_running = true;
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pthread_create(&threadid, NULL, &audio_thread, NULL);
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}
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void iron_a2_shutdown() {
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audio_running = false;
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}
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#endif
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