Implement gstreamer Hello World tutorial

http://gstreamer.freedesktop.org/data/doc/gstreamer/head/manual/html/chapter-helloworld.html

.gitignore

@@ -0,0 +1 @@
+/oggplay

Makefile

@@ -0,0 +1,9 @@
+TARGET := oggplay
+OBJS := oggplay.o
+CFLAGS := -Wall -O2 $$(pkg-config --cflags gstreamer-1.0)
+LIBS := $$(pkg-config --libs gstreamer-1.0)
+
+all: $(TARGET)
+
+$(TARGET): $(OBJS)
+	$(CC) -o $@ $(LDFLAGS) $^ $(LIBS)

oggplay.c

@@ -0,0 +1,107 @@
+#include <gst/gst.h>
+#include <glib.h>
+#include <stdio.h>
+
+static gboolean bus_call(GstBus *bus, GstMessage *msg, gpointer data);
+static void on_pad_added(GstElement *element, GstPad *pad, gpointer data);
+
+int main(int argc, char * argv[])
+{
+    GstElement *source, *demux, *decode, *conv, *sink, *pipeline;
+    GMainLoop *loop;
+    GstBus *bus;
+    guint bus_watch_id;
+
+    gst_init(NULL, NULL);
+    loop = g_main_loop_new(NULL, FALSE);
+
+    if (argc != 2)
+    {
+        g_printerr("Usage: %s <filename>\n", argv[0]);
+        return -1;
+    }
+
+    source = gst_element_factory_make("filesrc", "op_source");
+    demux = gst_element_factory_make("oggdemux", "op_demux");
+    decode = gst_element_factory_make("vorbisdec", "op_decode");
+    conv = gst_element_factory_make("audioconvert", "op_conv");
+    sink = gst_element_factory_make("autoaudiosink", "op_sink");
+    pipeline = gst_pipeline_new("op_pipeline");
+
+    if (!source || !demux || !decode || !sink || !pipeline)
+    {
+        g_printerr("Error creating something!\n");
+        return -1;
+    }
+
+    g_object_set(G_OBJECT(source), "location", argv[1], NULL);
+
+    bus = gst_pipeline_get_bus(GST_PIPELINE(pipeline));
+    bus_watch_id = gst_bus_add_watch(bus, bus_call, loop);
+    gst_object_unref(bus);
+
+    gst_bin_add_many(GST_BIN(pipeline),
+                     source, demux, decode, conv, sink, NULL);
+
+    gst_element_link(source, demux);
+    gst_element_link_many(decode, conv, sink, NULL);
+    g_signal_connect(demux, "pad-added", G_CALLBACK(on_pad_added), decode);
+
+    g_print("Beginning play\n");
+    gst_element_set_state(pipeline, GST_STATE_PLAYING);
+
+    g_print("Starting main loop\n");
+    g_main_loop_run(loop);
+
+    g_print("Main loop ended.\n");
+    gst_element_set_state(pipeline, GST_STATE_NULL);
+
+    gst_object_unref(GST_OBJECT(pipeline));
+    g_source_remove(bus_watch_id);
+    g_main_loop_unref(loop);
+
+    return 0;
+}
+
+static gboolean bus_call(GstBus *bus, GstMessage *msg, gpointer data)
+{
+    GMainLoop *loop = (GMainLoop *)data;
+
+    switch (GST_MESSAGE_TYPE(msg))
+    {
+    case GST_MESSAGE_EOS:
+        g_print("End of stream\n");
+        g_main_loop_quit(loop);
+        break;
+    case GST_MESSAGE_ERROR:
+        {
+            gchar *debug;
+            GError *error;
+
+            gst_message_parse_error(msg, &error, &debug);
+            g_free(debug);
+
+            g_printerr("Error: %s\n", error->message);
+            g_error_free(error);
+
+            g_main_loop_quit(loop);
+        }
+        break;
+    default:
+        break;
+    }
+
+    return TRUE;
+}
+
+static void on_pad_added(GstElement *element, GstPad *pad, gpointer data)
+{
+    GstPad *sinkpad;
+    GstElement *decode = (GstElement *)data;
+
+    g_print("Dynamic pad created, linking demux -> decode\n");
+
+    sinkpad = gst_element_get_static_pad(decode, "sink");
+    gst_pad_link(pad, sinkpad);
+    gst_object_unref(sinkpad);
+}