--- /dev/null
+#include <gst/gst.h>
+
+/* Functions below print the Capabilities in a human-friendly format */
+static gboolean print_field (GQuark field, const GValue * value, gpointer pfx) {
+ gchar *str = gst_value_serialize (value);
+
+ g_print ("%s %15s: %s\n", (gchar *) pfx, g_quark_to_string (field), str);
+ g_free (str);
+ return TRUE;
+}
+
+static void print_caps (const GstCaps * caps, const gchar * pfx) {
+ guint i;
+
+ g_return_if_fail (caps != NULL);
+
+ if (gst_caps_is_any (caps)) {
+ g_print ("%sANY\n", pfx);
+ return;
+ }
+ if (gst_caps_is_empty (caps)) {
+ g_print ("%sEMPTY\n", pfx);
+ return;
+ }
+
+ for (i = 0; i < gst_caps_get_size (caps); i++) {
+ GstStructure *structure = gst_caps_get_structure (caps, i);
+
+ g_print ("%s%s\n", pfx, gst_structure_get_name (structure));
+ gst_structure_foreach (structure, print_field, (gpointer) pfx);
+ }
+}
+
+/* Prints information about a Pad Template, including its Capabilities */
+static void print_pad_templates_information (GstElementFactory * factory) {
+ const GList *pads;
+ GstStaticPadTemplate *padtemplate;
+
+ g_print ("Pad Templates for %s:\n", gst_element_factory_get_longname (factory));
+ if (!gst_element_factory_get_num_pad_templates (factory)) {
+ g_print (" none\n");
+ return;
+ }
+
+ pads = gst_element_factory_get_static_pad_templates (factory);
+ while (pads) {
+ padtemplate = pads->data;
+ pads = g_list_next (pads);
+
+ if (padtemplate->direction == GST_PAD_SRC)
+ g_print (" SRC template: '%s'\n", padtemplate->name_template);
+ else if (padtemplate->direction == GST_PAD_SINK)
+ g_print (" SINK template: '%s'\n", padtemplate->name_template);
+ else
+ g_print (" UNKNOWN!!! template: '%s'\n", padtemplate->name_template);
+
+ if (padtemplate->presence == GST_PAD_ALWAYS)
+ g_print (" Availability: Always\n");
+ else if (padtemplate->presence == GST_PAD_SOMETIMES)
+ g_print (" Availability: Sometimes\n");
+ else if (padtemplate->presence == GST_PAD_REQUEST) {
+ g_print (" Availability: On request\n");
+ } else
+ g_print (" Availability: UNKNOWN!!!\n");
+
+ if (padtemplate->static_caps.string) {
+ GstCaps *caps;
+ g_print (" Capabilities:\n");
+ caps = gst_static_caps_get (&padtemplate->static_caps);
+ print_caps (caps, " ");
+ gst_caps_unref (caps);
+
+ }
+
+ g_print ("\n");
+ }
+}
+
+/* Shows the CURRENT capabilities of the requested pad in the given element */
+static void print_pad_capabilities (GstElement *element, gchar *pad_name) {
+ GstPad *pad = NULL;
+ GstCaps *caps = NULL;
+
+ /* Retrieve pad */
+ pad = gst_element_get_static_pad (element, pad_name);
+ if (!pad) {
+ g_printerr ("Could not retrieve pad '%s'\n", pad_name);
+ return;
+ }
+
+ /* Retrieve negotiated caps (or acceptable caps if negotiation is not finished yet) */
+ caps = gst_pad_get_current_caps (pad);
+ if (!caps)
+ caps = gst_pad_query_caps (pad, NULL);
+
+ /* Print and free */
+ g_print ("Caps for the %s pad:\n", pad_name);
+ print_caps (caps, " ");
+ gst_caps_unref (caps);
+ gst_object_unref (pad);
+}
+
+int main(int argc, char *argv[]) {
+ GstElement *pipeline, *source, *sink;
+ GstElementFactory *source_factory, *sink_factory;
+ GstBus *bus;
+ GstMessage *msg;
+ GstStateChangeReturn ret;
+ gboolean terminate = FALSE;
+
+ /* Initialize GStreamer */
+ gst_init (&argc, &argv);
+
+ /* Create the element factories */
+ source_factory = gst_element_factory_find ("audiotestsrc");
+ sink_factory = gst_element_factory_find ("autoaudiosink");
+ if (!source_factory || !sink_factory) {
+ g_printerr ("Not all element factories could be created.\n");
+ return -1;
+ }
+
+ /* Print information about the pad templates of these factories */
+ print_pad_templates_information (source_factory);
+ print_pad_templates_information (sink_factory);
+
+ /* Ask the factories to instantiate actual elements */
+ source = gst_element_factory_create (source_factory, "source");
+ sink = gst_element_factory_create (sink_factory, "sink");
+
+ /* Create the empty pipeline */
+ pipeline = gst_pipeline_new ("test-pipeline");
+
+ if (!pipeline || !source || !sink) {
+ g_printerr ("Not all elements could be created.\n");
+ return -1;
+ }
+
+ /* Build the pipeline */
+ gst_bin_add_many (GST_BIN (pipeline), source, sink, NULL);
+ if (gst_element_link (source, sink) != TRUE) {
+ g_printerr ("Elements could not be linked.\n");
+ gst_object_unref (pipeline);
+ return -1;
+ }
+
+ /* Print initial negotiated caps (in NULL state) */
+ g_print ("In NULL state:\n");
+ print_pad_capabilities (sink, "sink");
+
+ /* Start playing */
+ ret = gst_element_set_state (pipeline, GST_STATE_PLAYING);
+ if (ret == GST_STATE_CHANGE_FAILURE) {
+ g_printerr ("Unable to set the pipeline to the playing state (check the bus for error messages).\n");
+ }
+
+ /* Wait until error, EOS or State Change */
+ bus = gst_element_get_bus (pipeline);
+ do {
+ msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_ERROR | GST_MESSAGE_EOS |
+ GST_MESSAGE_STATE_CHANGED);
+
+ /* Parse message */
+ if (msg != NULL) {
+ GError *err;
+ gchar *debug_info;
+
+ switch (GST_MESSAGE_TYPE (msg)) {
+ case GST_MESSAGE_ERROR:
+ gst_message_parse_error (msg, &err, &debug_info);
+ g_printerr ("Error received from element %s: %s\n", GST_OBJECT_NAME (msg->src), err->message);
+ g_printerr ("Debugging information: %s\n", debug_info ? debug_info : "none");
+ g_clear_error (&err);
+ g_free (debug_info);
+ terminate = TRUE;
+ break;
+ case GST_MESSAGE_EOS:
+ g_print ("End-Of-Stream reached.\n");
+ terminate = TRUE;
+ break;
+ case GST_MESSAGE_STATE_CHANGED:
+ /* We are only interested in state-changed messages from the pipeline */
+ if (GST_MESSAGE_SRC (msg) == GST_OBJECT (pipeline)) {
+ GstState old_state, new_state, pending_state;
+ gst_message_parse_state_changed (msg, &old_state, &new_state, &pending_state);
+ g_print ("\nPipeline state changed from %s to %s:\n",
+ gst_element_state_get_name (old_state), gst_element_state_get_name (new_state));
+ /* Print the current capabilities of the sink element */
+ print_pad_capabilities (sink, "sink");
+ }
+ break;
+ default:
+ /* We should not reach here because we only asked for ERRORs, EOS and STATE_CHANGED */
+ g_printerr ("Unexpected message received.\n");
+ break;
+ }
+ gst_message_unref (msg);
+ }
+ } while (!terminate);
+
+ /* Free resources */
+ gst_object_unref (bus);
+ gst_element_set_state (pipeline, GST_STATE_NULL);
+ gst_object_unref (pipeline);
+ gst_object_unref (source_factory);
+ gst_object_unref (sink_factory);
+ return 0;
+}
+
--- /dev/null
+#include <gst/gst.h>
+
+int main(int argc, char *argv[]) {
+ GstElement *pipeline, *audio_source, *tee, *audio_queue, *audio_convert, *audio_resample, *audio_sink;
+ GstElement *video_queue, *visual, *video_convert, *video_sink;
+ GstBus *bus;
+ GstMessage *msg;
+ GstPad *tee_audio_pad, *tee_video_pad;
+ GstPad *queue_audio_pad, *queue_video_pad;
+
+ /* Initialize GStreamer */
+ gst_init (&argc, &argv);
+
+ /* Create the elements */
+ audio_source = gst_element_factory_make ("audiotestsrc", "audio_source");
+ tee = gst_element_factory_make ("tee", "tee");
+ audio_queue = gst_element_factory_make ("queue", "audio_queue");
+ audio_convert = gst_element_factory_make ("audioconvert", "audio_convert");
+ audio_resample = gst_element_factory_make ("audioresample", "audio_resample");
+ audio_sink = gst_element_factory_make ("autoaudiosink", "audio_sink");
+ video_queue = gst_element_factory_make ("queue", "video_queue");
+ visual = gst_element_factory_make ("wavescope", "visual");
+ video_convert = gst_element_factory_make ("videoconvert", "csp");
+ video_sink = gst_element_factory_make ("autovideosink", "video_sink");
+
+ /* Create the empty pipeline */
+ pipeline = gst_pipeline_new ("test-pipeline");
+
+ if (!pipeline || !audio_source || !tee || !audio_queue || !audio_convert || !audio_resample || !audio_sink ||
+ !video_queue || !visual || !video_convert || !video_sink) {
+ g_printerr ("Not all elements could be created.\n");
+ return -1;
+ }
+
+ /* Configure elements */
+ g_object_set (audio_source, "freq", 215.0f, NULL);
+ g_object_set (visual, "shader", 0, "style", 1, NULL);
+
+ /* Link all elements that can be automatically linked because they have "Always" pads */
+ gst_bin_add_many (GST_BIN (pipeline), audio_source, tee, audio_queue, audio_convert, audio_resample, audio_sink,
+ video_queue, visual, video_convert, video_sink, NULL);
+ if (gst_element_link_many (audio_source, tee, NULL) != TRUE ||
+ gst_element_link_many (audio_queue, audio_convert, audio_resample, audio_sink, NULL) != TRUE ||
+ gst_element_link_many (video_queue, visual, video_convert, video_sink, NULL) != TRUE) {
+ g_printerr ("Elements could not be linked.\n");
+ gst_object_unref (pipeline);
+ return -1;
+ }
+
+ /* Manually link the Tee, which has "Request" pads */
+ tee_audio_pad = gst_element_get_request_pad (tee, "src_%u");
+ g_print ("Obtained request pad %s for audio branch.\n", gst_pad_get_name (tee_audio_pad));
+ queue_audio_pad = gst_element_get_static_pad (audio_queue, "sink");
+ tee_video_pad = gst_element_get_request_pad (tee, "src_%u");
+ g_print ("Obtained request pad %s for video branch.\n", gst_pad_get_name (tee_video_pad));
+ queue_video_pad = gst_element_get_static_pad (video_queue, "sink");
+ if (gst_pad_link (tee_audio_pad, queue_audio_pad) != GST_PAD_LINK_OK ||
+ gst_pad_link (tee_video_pad, queue_video_pad) != GST_PAD_LINK_OK) {
+ g_printerr ("Tee could not be linked.\n");
+ gst_object_unref (pipeline);
+ return -1;
+ }
+ gst_object_unref (queue_audio_pad);
+ gst_object_unref (queue_video_pad);
+
+ /* Start playing the pipeline */
+ 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);
+
+ /* Release the request pads from the Tee, and unref them */
+ gst_element_release_request_pad (tee, tee_audio_pad);
+ gst_element_release_request_pad (tee, tee_video_pad);
+ gst_object_unref (tee_audio_pad);
+ gst_object_unref (tee_video_pad);
+
+ /* Free resources */
+ if (msg != NULL)
+ gst_message_unref (msg);
+ gst_object_unref (bus);
+ gst_element_set_state (pipeline, GST_STATE_NULL);
+
+ gst_object_unref (pipeline);
+ return 0;
+}
+