gstreamer/subprojects/gst-docs/examples/tutorials/playback-tutorial-6.c
Piotr Brzeziński 3bb8700577 macos: Add wrapper API to run a NSApplication in the main thread
On macOS, a Cocoa event loop is needed in the main thread to ensure
things like opening a GL window work correctly. In the past, this was
patched into glib via Cerbero, but that prevented us from updating it.
This workaround simply runs an NSApplication and then calls the
main function on a secondary thread, allowing GStreamer to correctly
display windows and/or system permission prompts, for example.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3532>
2022-12-13 17:50:32 +00:00

115 lines
3 KiB
C

#include <gst/gst.h>
#ifdef __APPLE__
#include <TargetConditionals.h>
#endif
/* playbin2 flags */
typedef enum
{
GST_PLAY_FLAG_VIS = (1 << 3) /* Enable rendering of visualizations when there is no video stream. */
} GstPlayFlags;
/* Return TRUE if this is a Visualization element */
static gboolean
filter_vis_features (GstPluginFeature * feature, gpointer data)
{
GstElementFactory *factory;
if (!GST_IS_ELEMENT_FACTORY (feature))
return FALSE;
factory = GST_ELEMENT_FACTORY (feature);
if (!g_strrstr (gst_element_factory_get_klass (factory), "Visualization"))
return FALSE;
return TRUE;
}
int
tutorial_main (int argc, char *argv[])
{
GstElement *pipeline, *vis_plugin;
GstBus *bus;
GstMessage *msg;
GList *list, *walk;
GstElementFactory *selected_factory = NULL;
guint flags;
/* Initialize GStreamer */
gst_init (&argc, &argv);
/* Get a list of all visualization plugins */
list =
gst_registry_feature_filter (gst_registry_get (), filter_vis_features,
FALSE, NULL);
/* Print their names */
g_print ("Available visualization plugins:\n");
for (walk = list; walk != NULL; walk = g_list_next (walk)) {
const gchar *name;
GstElementFactory *factory;
factory = GST_ELEMENT_FACTORY (walk->data);
name = gst_element_factory_get_longname (factory);
g_print (" %s\n", name);
if (selected_factory == NULL || g_str_has_prefix (name, "GOOM")) {
selected_factory = factory;
}
}
/* Don't use the factory if it's still empty */
/* e.g. no visualization plugins found */
if (!selected_factory) {
g_print ("No visualization plugins found!\n");
return -1;
}
/* We have now selected a factory for the visualization element */
g_print ("Selected '%s'\n",
gst_element_factory_get_longname (selected_factory));
vis_plugin = gst_element_factory_create (selected_factory, NULL);
if (!vis_plugin)
return -1;
/* Build the pipeline */
pipeline =
gst_parse_launch ("playbin uri=http://radio.hbr1.com:19800/ambient.ogg",
NULL);
/* Set the visualization flag */
g_object_get (pipeline, "flags", &flags, NULL);
flags |= GST_PLAY_FLAG_VIS;
g_object_set (pipeline, "flags", flags, NULL);
/* set vis plugin for playbin2 */
g_object_set (pipeline, "vis-plugin", vis_plugin, NULL);
/* Start playing */
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);
/* Free resources */
if (msg != NULL)
gst_message_unref (msg);
gst_plugin_feature_list_free (list);
gst_object_unref (bus);
gst_element_set_state (pipeline, GST_STATE_NULL);
gst_object_unref (pipeline);
return 0;
}
int
main (int argc, char *argv[])
{
#if defined(__APPLE__) && TARGET_OS_MAC && !TARGET_OS_IPHONE
return gst_macos_main (tutorial_main, argc, argv, NULL);
#else
return tutorial_main (argc, argv);
#endif
}