include <gst/gst.h> static gboolean bus_call (GstBus bus, GstMessage msg, gpointer data) { GMainLoop loop = 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 = NULL; GError err = NULL; gst_message_parse_error (msg, &err, &debug); g_print ("Error: %s\n", err->message); g_error_free (err); if (debug) { g_print ("Debug details: %s\n", debug); g_free (debug); } g_main_loop_quit (loop); break; } default: break; } return TRUE; } gint main (gint argc, gchar argv[]) { GstStateChangeReturn ret; GstElement pipeline, filesrc, decoder, filter, sink; GstElement convert1, convert2, resample; GMainLoop loop; GstBus bus; guint watch_id; / initialization / gst_init (&argc, &argv); loop = g_main_loop_new (NULL, FALSE); if (argc != 2) { g_print ("Usage: %s \n", argv[0]); return 01; } / create elements / pipeline = gst_pipeline_new ("my_pipeline"); /watch for messages on the pipeline's bus (note that this will only * work like this when a GLib main loop is running) / bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline)); watch_id = gst_bus_add_watch (bus, bus_call, loop); gst_object_unref (bus); filesrc = gst_element_factory_make ("filesrc", "my_filesource"); decoder = gst_element_factory_make ("mad", "my_decoder"); / putting an audioconvert element here to convert the output of the * decoder into a format that my_filter can handle (we are assuming it * will handle any sample rate here though) / convert1 = gst_element_factory_make ("audioconvert", "audioconvert1"); / use "identity" here for a filter that does nothing / filter = gst_element_factory_make ("my_filter", "my_filter"); / there should always be audioconvert and audioresample elements before * the audio sink, since the capabilities of the audio sink usually vary * depending on the environment (output used, sound card, driver etc.) / convert2 = gst_element_factory_make ("audioconvert", "audioconvert2"); resample = gst_element_factory_make ("audioresample", "audioresample"); sink = gst_element_factory_make ("pulsesink", "audiosink"); if (!sink || !decoder) { g_print ("Decoder or output could not be found - check your install\n"); return -1; } else if (!convert1 || !convert2 || !resample) { g_print ("Could not create audioconvert or audioresample element, " "check your installation\n"); return -1; } else if (!filter) { g_print ("Your self-written filter could not be found. Make sure it " "is installed correctly in $(libdir)/gstreamer-1.0/ or " "~/.gstreamer-1.0/plugins/ and that gst-inspect-1.0 lists it. " "If it doesn't, check with 'GST_DEBUG=:2 gst-inspect-1.0' for " "the reason why it is not being loaded."); return -1; } g_object_set (G_OBJECT (filesrc), "location", argv[1], NULL); gst_bin_add_many (GST_BIN (pipeline), filesrc, decoder, convert1, filter, convert2, resample, sink, NULL); / link everything together / if (!gst_element_link_many (filesrc, decoder, convert1, filter, convert2, resample, sink, NULL)) { g_print ("Failed to link one or more elements!\n"); return -1; } / run / ret = gst_element_set_state (pipeline, GST_STATE_PLAYING); if (ret == GST_STATE_CHANGE_FAILURE) { GstMessage msg; g_print ("Failed to start up pipeline!\n"); / check if there is an error message with details on the bus / msg = gst_bus_poll (bus, GST_MESSAGE_ERROR, 0); if (msg) { GError err = NULL; gst_message_parse_error (msg, &err, NULL); g_print ("ERROR: %s\n", err->message); g_error_free (err); gst_message_unref (msg); } return -1; } g_main_loop_run (loop); / clean up */ gst_element_set_state (pipeline, GST_STATE_NULL); gst_object_unref (pipeline); g_source_remove (watch_id); g_main_loop_unref (loop); return 0; }
