1 files changed, 94 insertions, 0 deletions
diff --git a/tuner.c b/tuner.c
new file mode 100644
index 0000000..0747f3f
--- /dev/null
+++ b/tuner.c
@@ -0,0 +1,94 @@
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <signal.h>
+#include <alsa/asoundlib.h>
+
+#define SAMPLE_RATE 8000
+#define BUFFER_SIZE 4096
+
+static int capturing = 1;
+
+static void handle_signals(int signum __attribute__((unused)))
+{
+	capturing = 0;
+}
+
+static int set_alsa_params(snd_pcm_t *pcm_handle)
+{
+	snd_pcm_hw_params_t *hwparams;
+	unsigned int rate = SAMPLE_RATE;
+	snd_pcm_uframes_t bufsize = BUFFER_SIZE;
+
+	snd_pcm_hw_params_alloca(&hwparams);
+
+	if (snd_pcm_hw_params_any(pcm_handle, hwparams) < 0) {
+		fprintf(stderr, "Failed configuring device\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_access(pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED) < 0) {
+		fprintf(stderr, "Failed setting access mode\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_format(pcm_handle, hwparams, SND_PCM_FORMAT_S16_LE) < 0) {
+		fprintf(stderr, "Failed setting format\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams, &rate, 0) < 0) {
+		fprintf(stderr, "Failed setting sample rate\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_buffer_size_near(pcm_handle, hwparams, &bufsize) < 0) {
+		fprintf(stderr, "Failed setting buffer size\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_channels(pcm_handle, hwparams, 1) < 0) {
+		fprintf(stderr, "Failed setting channel number\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params(pcm_handle, hwparams) < 0) {
+		fprintf(stderr, "Failed applying hardware parameters\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+static void capture(snd_pcm_t *pcm_handle)
+{
+	char tonebuf[BUFFER_SIZE];
+	int n_frames = 0;
+	FILE* f = fopen("capture.raw", "w");
+
+	while(capturing) {
+		while ((n_frames = snd_pcm_readi(pcm_handle, tonebuf, sizeof(tonebuf) / 2)) < 0) {
+			snd_pcm_prepare(pcm_handle);
+			printf("overrun\n");
+		}
+		fwrite(tonebuf, n_frames*2, 1, f);
+	}
+	fclose(f);
+}
+
+int main()
+{
+	snd_pcm_t *pcm_handle;
+
+	if (snd_pcm_open(&pcm_handle, "default", SND_PCM_STREAM_CAPTURE, 0) < 0) {
+		fprintf(stderr, "Failed opening device for capturing\n");
+		return 1;
+	}
+
+	if (set_alsa_params(pcm_handle) < 0) {
+		return 1;
+	}
+
+	signal(SIGINT, handle_signals);
+	signal(SIGTERM, handle_signals);
+
+	capture(pcm_handle);
+
+	snd_pcm_close(pcm_handle);
+
+	return 0;
+}