#include #include

//消息处理函数

static gboolean bus_call(GstBus * bus, GstMessage *msg, gpointer data)

{

GMainLoop*loop = (GMainLoop *) data;switch(GST_MESSAGE_TYPE(msg))

{caseGST_MESSAGE_EOS:

g_print("End of stream\n");

g_main_loop_quit(loop);break;caseGST_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;

}returnTRUE;

}int main(int argc, char *argv[])

{

GMainLoop*loop;

GstElement*pipeline, *source, *decoder, *sink; //定义组件

GstBus *bus;

gst_init(&argc, &argv);

loop= g_main_loop_new(NULL, FALSE); //创建主循环，在执行 g_main_loop_run后正式开始循环

if (argc != 2)

{

g_printerr("Usage:%s \n", argv[0]);return -1;

}//创建管道和组件

pipeline = gst_pipeline_new("audio-player");

source= gst_element_factory_make("filesrc", "file-source");

decoder= gst_element_factory_make("mad", "mad-decoder");

sink= gst_element_factory_make("autoaudiosink", "audio-output");if (!pipeline || !source || !decoder || !sink)

{

g_printerr("One element could not be created.Exiting.\n");return -1;

}//设置source的location参数,即文件地址

g_object_set(G_OBJECT(source), "location", argv[1], NULL);//得到管道的消息总线

bus =gst_pipeline_get_bus(GST_PIPELINE(pipeline));//添加消息监视器

gst_bus_add_watch(bus, bus_call, loop);

gst_object_unref(bus);//把组件添加到管道中.管道是一个特殊的组件，可以更好的让数据流动

gst_bin_add_many(GST_BIN(pipeline), source, decoder, sink, NULL);//依次连接组件

gst_element_link_many(source, decoder, sink, NULL);//开始播放

gst_element_set_state(pipeline, GST_STATE_PLAYING);

g_print("Running\n");//开始循环

g_main_loop_run(loop);

g_print("Returned,stopping playback\n");

gst_element_set_state(pipeline, GST_STATE_NULL);

gst_object_unref(GST_OBJECT(pipeline));return 0;

}