Update
This commit is contained in:
Akkariin Meiko
@@ -0,0 +1,224 @@
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#include <gst/gst.h>
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/* Functions below print the Capabilities in a human-friendly format */
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static gboolean
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print_field (GQuark field, const GValue * value, gpointer pfx)
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{
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gchar *str = gst_value_serialize (value);
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g_print ("%s %15s: %s\n", (gchar *) pfx, g_quark_to_string (field), str);
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g_free (str);
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return TRUE;
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}
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static void
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print_caps (const GstCaps * caps, const gchar * pfx)
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{
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guint i;
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g_return_if_fail (caps != NULL);
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if (gst_caps_is_any (caps)) {
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g_print ("%sANY\n", pfx);
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return;
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}
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if (gst_caps_is_empty (caps)) {
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g_print ("%sEMPTY\n", pfx);
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return;
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}
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for (i = 0; i < gst_caps_get_size (caps); i++) {
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GstStructure *structure = gst_caps_get_structure (caps, i);
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g_print ("%s%s\n", pfx, gst_structure_get_name (structure));
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gst_structure_foreach (structure, print_field, (gpointer) pfx);
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}
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}
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/* Prints information about a Pad Template, including its Capabilities */
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static void
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print_pad_templates_information (GstElementFactory * factory)
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{
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const GList *pads;
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GstStaticPadTemplate *padtemplate;
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g_print ("Pad Templates for %s:\n",
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gst_element_factory_get_longname (factory));
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if (!gst_element_factory_get_num_pad_templates (factory)) {
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g_print (" none\n");
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return;
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}
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pads = gst_element_factory_get_static_pad_templates (factory);
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while (pads) {
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padtemplate = pads->data;
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pads = g_list_next (pads);
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if (padtemplate->direction == GST_PAD_SRC)
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g_print (" SRC template: '%s'\n", padtemplate->name_template);
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else if (padtemplate->direction == GST_PAD_SINK)
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g_print (" SINK template: '%s'\n", padtemplate->name_template);
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else
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g_print (" UNKNOWN!!! template: '%s'\n", padtemplate->name_template);
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if (padtemplate->presence == GST_PAD_ALWAYS)
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g_print (" Availability: Always\n");
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else if (padtemplate->presence == GST_PAD_SOMETIMES)
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g_print (" Availability: Sometimes\n");
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else if (padtemplate->presence == GST_PAD_REQUEST)
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g_print (" Availability: On request\n");
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else
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g_print (" Availability: UNKNOWN!!!\n");
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if (padtemplate->static_caps.string) {
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GstCaps *caps;
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g_print (" Capabilities:\n");
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caps = gst_static_caps_get (&padtemplate->static_caps);
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print_caps (caps, " ");
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gst_caps_unref (caps);
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}
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g_print ("\n");
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}
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}
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/* Shows the CURRENT capabilities of the requested pad in the given element */
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static void
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print_pad_capabilities (GstElement * element, gchar * pad_name)
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{
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GstPad *pad = NULL;
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GstCaps *caps = NULL;
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/* Retrieve pad */
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pad = gst_element_get_static_pad (element, pad_name);
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if (!pad) {
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g_printerr ("Could not retrieve pad '%s'\n", pad_name);
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return;
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}
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/* Retrieve negotiated caps (or acceptable caps if negotiation is not finished yet) */
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caps = gst_pad_get_current_caps (pad);
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if (!caps)
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caps = gst_pad_query_caps (pad, NULL);
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/* Print and free */
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g_print ("Caps for the %s pad:\n", pad_name);
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print_caps (caps, " ");
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gst_caps_unref (caps);
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gst_object_unref (pad);
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}
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int
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main (int argc, char *argv[])
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{
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GstElement *pipeline, *source, *sink;
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GstElementFactory *source_factory, *sink_factory;
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GstBus *bus;
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GstMessage *msg;
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GstStateChangeReturn ret;
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gboolean terminate = FALSE;
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/* Initialize GStreamer */
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gst_init (&argc, &argv);
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/* Create the element factories */
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source_factory = gst_element_factory_find ("audiotestsrc");
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sink_factory = gst_element_factory_find ("autoaudiosink");
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if (!source_factory || !sink_factory) {
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g_printerr ("Not all element factories could be created.\n");
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return -1;
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}
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/* Print information about the pad templates of these factories */
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print_pad_templates_information (source_factory);
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print_pad_templates_information (sink_factory);
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/* Ask the factories to instantiate actual elements */
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source = gst_element_factory_create (source_factory, "source");
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sink = gst_element_factory_create (sink_factory, "sink");
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/* Create the empty pipeline */
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pipeline = gst_pipeline_new ("test-pipeline");
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if (!pipeline || !source || !sink) {
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g_printerr ("Not all elements could be created.\n");
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return -1;
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}
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/* Build the pipeline */
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gst_bin_add_many (GST_BIN (pipeline), source, sink, NULL);
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if (gst_element_link (source, sink) != TRUE) {
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g_printerr ("Elements could not be linked.\n");
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gst_object_unref (pipeline);
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return -1;
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}
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/* Print initial negotiated caps (in NULL state) */
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g_print ("In NULL state:\n");
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print_pad_capabilities (sink, "sink");
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/* Start playing */
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ret = gst_element_set_state (pipeline, GST_STATE_PLAYING);
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if (ret == GST_STATE_CHANGE_FAILURE) {
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g_printerr
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("Unable to set the pipeline to the playing state (check the bus for error messages).\n");
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}
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/* Wait until error, EOS or State Change */
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bus = gst_element_get_bus (pipeline);
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do {
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msg =
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gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE,
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GST_MESSAGE_ERROR | GST_MESSAGE_EOS | GST_MESSAGE_STATE_CHANGED);
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/* Parse message */
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if (msg != NULL) {
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GError *err;
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gchar *debug_info;
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switch (GST_MESSAGE_TYPE (msg)) {
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case GST_MESSAGE_ERROR:
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gst_message_parse_error (msg, &err, &debug_info);
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g_printerr ("Error received from element %s: %s\n",
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GST_OBJECT_NAME (msg->src), err->message);
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g_printerr ("Debugging information: %s\n",
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debug_info ? debug_info : "none");
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g_clear_error (&err);
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g_free (debug_info);
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terminate = TRUE;
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break;
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case GST_MESSAGE_EOS:
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g_print ("End-Of-Stream reached.\n");
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terminate = TRUE;
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break;
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case GST_MESSAGE_STATE_CHANGED:
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/* We are only interested in state-changed messages from the pipeline */
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if (GST_MESSAGE_SRC (msg) == GST_OBJECT (pipeline)) {
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GstState old_state, new_state, pending_state;
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gst_message_parse_state_changed (msg, &old_state, &new_state,
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&pending_state);
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g_print ("\nPipeline state changed from %s to %s:\n",
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gst_element_state_get_name (old_state),
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gst_element_state_get_name (new_state));
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/* Print the current capabilities of the sink element */
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print_pad_capabilities (sink, "sink");
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}
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break;
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default:
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/* We should not reach here because we only asked for ERRORs, EOS and STATE_CHANGED */
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g_printerr ("Unexpected message received.\n");
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break;
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}
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gst_message_unref (msg);
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}
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} while (!terminate);
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/* Free resources */
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gst_object_unref (bus);
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gst_element_set_state (pipeline, GST_STATE_NULL);
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gst_object_unref (pipeline);
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gst_object_unref (source_factory);
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gst_object_unref (sink_factory);
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return 0;
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}
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