hop

main.c

@@ -0,0 +1,125 @@
+/*
+ * Simple sound playback using ALSA API and libasound.
+ *
+ * Compile:
+ * $ cc -o play sound_playback.c -lasound
+ * 
+ * Usage:
+ * $ ./play <sample_rate> <channels> <seconds> < <file>
+ * 
+ * Examples:
+ * $ ./play 44100 2 5 < /dev/urandom
+ * $ ./play 22050 1 8 < /path/to/file.wav
+ *
+ * Copyright (C) 2009 Alessandro Ghedini <alessandro@ghedini.me>
+ * --------------------------------------------------------------
+ * "THE BEER-WARE LICENSE" (Revision 42):
+ * Alessandro Ghedini wrote this file. As long as you retain this
+ * notice you can do whatever you want with this stuff. If we
+ * meet some day, and you think this stuff is worth it, you can
+ * buy me a beer in return.
+ * --------------------------------------------------------------
+ */
+
+#include <alsa/asoundlib.h>
+#include <stdio.h>
+
+#define PCM_DEVICE "default"
+
+int main(int argc, char **argv) {
+	unsigned int pcm, tmp, dir;
+	int rate, channels, seconds;
+	snd_pcm_t *pcm_handle;
+	snd_pcm_hw_params_t *params;
+	snd_pcm_uframes_t frames;
+	char *buff;
+	int buff_size, loops;
+
+	if (argc < 4) {
+		printf("Usage: %s <sample_rate> <channels> <seconds>\n",
+								argv[0]);
+		return -1;
+	}
+
+	rate 	 = atoi(argv[1]);
+	channels = atoi(argv[2]);
+	seconds  = atoi(argv[3]);
+
+	/* Open the PCM device in playback mode */
+	if (pcm = snd_pcm_open(&pcm_handle, PCM_DEVICE,
+					SND_PCM_STREAM_PLAYBACK, 0) < 0) 
+		printf("ERROR: Can't open \"%s\" PCM device. %s\n",
+					PCM_DEVICE, snd_strerror(pcm));
+
+	/* Allocate parameters object and fill it with default values*/
+	snd_pcm_hw_params_alloca(&params);
+
+	snd_pcm_hw_params_any(pcm_handle, params);
+
+	/* Set parameters */
+	if (pcm = snd_pcm_hw_params_set_access(pcm_handle, params,
+					SND_PCM_ACCESS_RW_INTERLEAVED) < 0) 
+		printf("ERROR: Can't set interleaved mode. %s\n", snd_strerror(pcm));
+
+	if (pcm = snd_pcm_hw_params_set_format(pcm_handle, params,
+						SND_PCM_FORMAT_S16_LE) < 0) 
+		printf("ERROR: Can't set format. %s\n", snd_strerror(pcm));
+
+	if (pcm = snd_pcm_hw_params_set_channels(pcm_handle, params, channels) < 0) 
+		printf("ERROR: Can't set channels number. %s\n", snd_strerror(pcm));
+
+	if (pcm = snd_pcm_hw_params_set_rate_near(pcm_handle, params, &rate, 0) < 0) 
+		printf("ERROR: Can't set rate. %s\n", snd_strerror(pcm));
+
+	/* Write parameters */
+	if (pcm = snd_pcm_hw_params(pcm_handle, params) < 0)
+		printf("ERROR: Can't set harware parameters. %s\n", snd_strerror(pcm));
+
+	/* Resume information */
+	printf("PCM name: '%s'\n", snd_pcm_name(pcm_handle));
+
+	printf("PCM state: %s\n", snd_pcm_state_name(snd_pcm_state(pcm_handle)));
+
+	snd_pcm_hw_params_get_channels(params, &tmp);
+	printf("channels: %i ", tmp);
+
+	if (tmp == 1)
+		printf("(mono)\n");
+	else if (tmp == 2)
+		printf("(stereo)\n");
+
+	snd_pcm_hw_params_get_rate(params, &tmp, 0);
+	printf("rate: %d bps\n", tmp);
+
+	printf("seconds: %d\n", seconds);	
+
+	/* Allocate buffer to hold single period */
+	snd_pcm_hw_params_get_period_size(params, &frames, 0);
+
+	buff_size = frames * channels * 2 /* 2 -> sample size */;
+	buff = (char *) malloc(buff_size);
+
+	snd_pcm_hw_params_get_period_time(params, &tmp, NULL);
+
+	for (loops = (seconds * 1000000) / tmp; loops > 0; loops--) {
+
+		if (pcm = read(0, buff, buff_size) == 0) {
+			printf("Early end of file.\n");
+			return 0;
+		}
+
+		if (pcm = snd_pcm_writei(pcm_handle, buff, frames) == -EPIPE) {
+			printf("XRUN.\n");
+			snd_pcm_prepare(pcm_handle);
+		} else if (pcm < 0) {
+			printf("ERROR. Can't write to PCM device. %s\n", snd_strerror(pcm));
+		}
+
+	}
+
+	snd_pcm_drain(pcm_handle);
+	snd_pcm_close(pcm_handle);
+	free(buff);
+
+	return 0;
+}