234 lines
6.5 KiB
C
234 lines
6.5 KiB
C
#include <kinc/audio2/audio.h>
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#include <alsa/asoundlib.h>
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#include <errno.h>
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#include <poll.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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// apt-get install libasound2-dev
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kinc_a2_buffer_t a2_buffer;
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pthread_t threadid;
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bool audioRunning = false;
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snd_pcm_t *playback_handle;
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short buf[4096 * 4];
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static unsigned int samples_per_second = 44100;
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uint32_t kinc_a2_samples_per_second(void) {
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return samples_per_second;
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}
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void copySample(void *buffer) {
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float left_value = *(float *)&a2_buffer.channels[0][a2_buffer.read_location];
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float right_value = *(float *)&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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int playback_callback(snd_pcm_sframes_t nframes) {
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int err = 0;
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if (kinc_a2_internal_callback(&a2_buffer, nframes)) {
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int ni = 0;
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while (ni < nframes) {
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int i = 0;
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for (; ni < nframes && i < 4096 * 2; ++i, ++ni) {
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copySample(&buf[i * 2]);
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}
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int err2;
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if ((err2 = snd_pcm_writei(playback_handle, buf, i)) < 0) {
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fprintf(stderr, "write failed (%s)\n", snd_strerror(err2));
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}
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err += err2;
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}
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}
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return err;
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}
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bool tryToRecover(snd_pcm_t *handle, int errorCode) {
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switch (-errorCode) {
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case EINTR:
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case EPIPE:
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case ESPIPE:
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#if !defined(__FreeBSD__)
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case ESTRPIPE:
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#endif
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{
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int recovered = snd_pcm_recover(playback_handle, errorCode, 1);
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if (recovered != 0) {
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fprintf(stderr, "unable to recover from ALSA error code=%i\n", errorCode);
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return false;
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}
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else {
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fprintf(stdout, "recovered from ALSA error code=%i\n", errorCode);
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return true;
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}
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}
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default:
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fprintf(stderr, "unhandled ALSA error code=%i\n", errorCode);
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return false;
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}
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}
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void *doAudio(void *arg) {
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snd_pcm_hw_params_t *hw_params;
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snd_pcm_sw_params_t *sw_params;
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snd_pcm_sframes_t frames_to_deliver;
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int err;
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if ((err = snd_pcm_open(&playback_handle, "default", SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
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fprintf(stderr, "cannot open audio device default (%s)\n", snd_strerror(err));
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return NULL;
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}
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if ((err = snd_pcm_hw_params_malloc(&hw_params)) < 0) {
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fprintf(stderr, "cannot allocate hardware parameter structure (%s)\n", snd_strerror(err));
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return NULL;
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}
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if ((err = snd_pcm_hw_params_any(playback_handle, hw_params)) < 0) {
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fprintf(stderr, "cannot initialize hardware parameter structure (%s)\n", snd_strerror(err));
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return NULL;
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}
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if ((err = snd_pcm_hw_params_set_access(playback_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
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fprintf(stderr, "cannot set access type (%s)\n", snd_strerror(err));
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return NULL;
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}
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if ((err = snd_pcm_hw_params_set_format(playback_handle, hw_params, SND_PCM_FORMAT_S16_LE)) < 0) {
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fprintf(stderr, "cannot set sample format (%s)\n", snd_strerror(err));
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return NULL;
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}
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int dir = 0;
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if ((err = snd_pcm_hw_params_set_rate_near(playback_handle, hw_params, &samples_per_second, &dir)) < 0) {
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fprintf(stderr, "cannot set sample rate (%s)\n", snd_strerror(err));
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return NULL;
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}
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if ((err = snd_pcm_hw_params_set_channels(playback_handle, hw_params, 2)) < 0) {
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fprintf(stderr, "cannot set channel count (%s)\n", snd_strerror(err));
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return NULL;
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}
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snd_pcm_uframes_t bufferSize = samples_per_second / 8;
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if (((err = snd_pcm_hw_params_set_buffer_size(playback_handle, hw_params, bufferSize)) < 0 &&
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(snd_pcm_hw_params_set_buffer_size_near(playback_handle, hw_params, &bufferSize)) < 0)) {
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fprintf(stderr, "cannot set buffer size (%s)\n", snd_strerror(err));
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return NULL;
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}
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if ((err = snd_pcm_hw_params(playback_handle, hw_params)) < 0) {
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fprintf(stderr, "cannot set parameters (%s)\n", snd_strerror(err));
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return NULL;
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}
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snd_pcm_hw_params_free(hw_params);
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/* tell ALSA to wake us up whenever 4096 or more frames
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of playback data can be delivered. Also, tell
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ALSA that we'll start the device ourselves.
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*/
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if ((err = snd_pcm_sw_params_malloc(&sw_params)) < 0) {
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fprintf(stderr, "cannot allocate software parameters structure (%s)\n", snd_strerror(err));
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return NULL;
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}
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if ((err = snd_pcm_sw_params_current(playback_handle, sw_params)) < 0) {
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fprintf(stderr, "cannot initialize software parameters structure (%s)\n", snd_strerror(err));
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return NULL;
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}
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if ((err = snd_pcm_sw_params_set_avail_min(playback_handle, sw_params, 4096)) < 0) {
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fprintf(stderr, "cannot set minimum available count (%s)\n", snd_strerror(err));
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return NULL;
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}
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if ((err = snd_pcm_sw_params_set_start_threshold(playback_handle, sw_params, 0U)) < 0) {
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fprintf(stderr, "cannot set start mode (%s)\n", snd_strerror(err));
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return NULL;
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}
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if ((err = snd_pcm_sw_params(playback_handle, sw_params)) < 0) {
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fprintf(stderr, "cannot set software parameters (%s)\n", snd_strerror(err));
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return NULL;
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}
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/* the interface will interrupt the kernel every 4096 frames, and ALSA
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will wake up this program very soon after that.
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*/
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if ((err = snd_pcm_prepare(playback_handle)) < 0) {
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fprintf(stderr, "cannot prepare audio interface for use (%s)\n", snd_strerror(err));
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return NULL;
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}
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while (audioRunning) {
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/* wait till the interface is ready for data, or 1 second
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has elapsed.
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*/
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if ((err = snd_pcm_wait(playback_handle, 1000)) < 0) {
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fprintf(stderr, "poll failed (%s)\n", strerror(errno));
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break;
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}
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/* find out how much space is available for playback data */
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if ((frames_to_deliver = snd_pcm_avail_update(playback_handle)) < 0) {
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if (!tryToRecover(playback_handle, frames_to_deliver)) {
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// break;
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}
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}
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else {
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// frames_to_deliver = frames_to_deliver > 4096 ? 4096 : frames_to_deliver;
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/* deliver the data */
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int delivered = playback_callback(frames_to_deliver);
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if (delivered != frames_to_deliver) {
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fprintf(stderr, "playback callback failed (delivered %i / %ld frames)\n", delivered, frames_to_deliver);
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// break;
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}
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}
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}
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snd_pcm_close(playback_handle);
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return NULL;
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}
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static bool initialized = false;
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void kinc_a2_init() {
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if (initialized) {
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return;
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}
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kinc_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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audioRunning = true;
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pthread_create(&threadid, NULL, &doAudio, NULL);
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}
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void kinc_a2_update() {}
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void kinc_a2_shutdown() {
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audioRunning = false;
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}
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