some sample with gstreamer

playback/6/Makefile

@@ -0,0 +1,9 @@
+SRC = $(wildcard *.c)
+TARGET = $(patsubst %.c, %, $(SRC))
+all: $(TARGET)
+
+%:%.c
+	gcc -o $@ $< `pkg-config --libs --cflags gstreamer-1.0`
+
+clean:
+	rm -f $(TARGET)

playback/6/audio.c

@@ -0,0 +1,90 @@
+#include <gst/gst.h>
+
+/* playbin flags */
+typedef enum {
+  GST_PLAY_FLAG_VIS           = (1 << 3) /* Enable rendering of visualizations when there is no video stream. */
+} GstPlayFlags;
+
+/* Return TRUE if this is a Visualization element */
+static gboolean filter_vis_features (GstPluginFeature *feature, gpointer data) {
+  GstElementFactory *factory;
+
+  if (!GST_IS_ELEMENT_FACTORY (feature))
+    return FALSE;
+  factory = GST_ELEMENT_FACTORY (feature);
+  if (!g_strrstr (gst_element_factory_get_klass (factory), "Visualization"))
+    return FALSE;
+
+  return TRUE;
+}
+
+int main(int argc, char *argv[]) {
+  GstElement *pipeline, *vis_plugin;
+  GstBus *bus;
+  GstMessage *msg;
+  GList *list, *walk;
+  GstElementFactory *selected_factory = NULL;
+  guint flags;
+
+  /* Initialize GStreamer */
+  gst_init (&argc, &argv);
+
+  /* Get a list of all visualization plugins */
+  list = gst_registry_feature_filter (gst_registry_get (), filter_vis_features, FALSE, NULL);
+
+  /* Print their names */
+  g_print("Available visualization plugins:\n");
+  for (walk = list; walk != NULL; walk = g_list_next (walk)) {
+    const gchar *name;
+    GstElementFactory *factory;
+
+    factory = GST_ELEMENT_FACTORY (walk->data);
+    name = gst_element_factory_get_longname (factory);
+    g_print("  %s\n", name);
+
+    if (selected_factory == NULL || g_str_has_prefix (name, "GOOM")) {
+      selected_factory = factory;
+    }
+  }
+
+  /* Don't use the factory if it's still empty */
+  /* e.g. no visualization plugins found */
+  if (!selected_factory) {
+    g_print ("No visualization plugins found!\n");
+    return -1;
+  }
+
+  /* We have now selected a factory for the visualization element */
+  g_print ("Selected '%s'\n", gst_element_factory_get_longname (selected_factory));
+  vis_plugin = gst_element_factory_create (selected_factory, NULL);
+  if (!vis_plugin)
+    return -1;
+
+  /* Build the pipeline */
+  pipeline = gst_parse_launch ("playbin uri=file:///home/ye/Music/1.wav", NULL);
+
+  /* Set the visualization flag */
+  g_object_get (pipeline, "flags", &flags, NULL);
+  flags |= GST_PLAY_FLAG_VIS;
+  g_object_set (pipeline, "flags", flags, NULL);
+
+  /* set vis plugin for playbin */
+  g_object_set (pipeline, "vis-plugin", vis_plugin, NULL);
+
+  /* Start playing */
+  gst_element_set_state (pipeline, GST_STATE_PLAYING);
+
+  /* Wait until error or EOS */
+  bus = gst_element_get_bus (pipeline);
+  msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_ERROR | GST_MESSAGE_EOS);
+
+  /* Free resources */
+  if (msg != NULL)
+    gst_message_unref (msg);
+  gst_plugin_feature_list_free (list);
+  gst_object_unref (bus);
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  gst_object_unref (pipeline);
+  return 0;
+}
+