gstreamer/subprojects/gst-docs/examples/tutorials/basic-tutorial-12.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

122 lines
3 KiB
C

#include <gst/gst.h>
#include <string.h>
#ifdef __APPLE__
#include <TargetConditionals.h>
#endif
typedef struct _CustomData
{
gboolean is_live;
GstElement *pipeline;
GMainLoop *loop;
} CustomData;
static void
cb_message (GstBus * bus, GstMessage * msg, CustomData * data)
{
switch (GST_MESSAGE_TYPE (msg)) {
case GST_MESSAGE_ERROR:{
GError *err;
gchar *debug;
gst_message_parse_error (msg, &err, &debug);
g_print ("Error: %s\n", err->message);
g_error_free (err);
g_free (debug);
gst_element_set_state (data->pipeline, GST_STATE_READY);
g_main_loop_quit (data->loop);
break;
}
case GST_MESSAGE_EOS:
/* end-of-stream */
gst_element_set_state (data->pipeline, GST_STATE_READY);
g_main_loop_quit (data->loop);
break;
case GST_MESSAGE_BUFFERING:{
gint percent = 0;
/* If the stream is live, we do not care about buffering. */
if (data->is_live)
break;
gst_message_parse_buffering (msg, &percent);
g_print ("Buffering (%3d%%)\r", percent);
/* Wait until buffering is complete before start/resume playing */
if (percent < 100)
gst_element_set_state (data->pipeline, GST_STATE_PAUSED);
else
gst_element_set_state (data->pipeline, GST_STATE_PLAYING);
break;
}
case GST_MESSAGE_CLOCK_LOST:
/* Get a new clock */
gst_element_set_state (data->pipeline, GST_STATE_PAUSED);
gst_element_set_state (data->pipeline, GST_STATE_PLAYING);
break;
default:
/* Unhandled message */
break;
}
}
int
tutorial_main (int argc, char *argv[])
{
GstElement *pipeline;
GstBus *bus;
GstStateChangeReturn ret;
GMainLoop *main_loop;
CustomData data;
/* Initialize GStreamer */
gst_init (&argc, &argv);
/* Initialize our data structure */
memset (&data, 0, sizeof (data));
/* Build the pipeline */
pipeline =
gst_parse_launch
("playbin uri=https://www.freedesktop.org/software/gstreamer-sdk/data/media/sintel_trailer-480p.webm",
NULL);
bus = gst_element_get_bus (pipeline);
/* 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.\n");
gst_object_unref (pipeline);
return -1;
} else if (ret == GST_STATE_CHANGE_NO_PREROLL) {
data.is_live = TRUE;
}
main_loop = g_main_loop_new (NULL, FALSE);
data.loop = main_loop;
data.pipeline = pipeline;
gst_bus_add_signal_watch (bus);
g_signal_connect (bus, "message", G_CALLBACK (cb_message), &data);
g_main_loop_run (main_loop);
/* Free resources */
g_main_loop_unref (main_loop);
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
}