move from private r&d repo

include/audio.h

@@ -0,0 +1,29 @@
+#ifndef AUDIOCAPTURE_H
+#define AUDIOCAPTURE_H
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <alsa/asoundlib.h>
+#include <alsa/control.h>
+#include <alsa/pcm.h>
+
+// NOTE: find this via `arecord -l`
+#define ALSA_MIC_HARDWARE_DEVICE "hw:3"
+#define ALSA_SPEAKER_HARDWARE_DEVICE "default"
+
+// Captures audio for given seconds, and returns file name that we captured the
+// audio into
+char *audio_capture(uint seconds);
+
+/* count: how many bytes in the buffer
+ *  returns int: 0 if success, -1 if failure
+ *  NOTE: This function assumes that the audio data is using:
+ *  - linear16 formatting (each sample is 16 bits)
+ *  - one channel (1 sample)
+ *  - with 48000 HZ sampling rate
+ *  Hence, it's 2 bytes per frame.
+ */
+int audio_play(char *buf, size_t byte_count);
+
+#endif // AUDIOCAPTURE_H