gstreamer/subprojects/gst-docs/examples/tutorials/basic-tutorial-7.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

112 lines
4 KiB
C

#include <gst/gst.h>
#ifdef __APPLE__
#include <TargetConditionals.h>
#endif
int
tutorial_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", "video_convert");
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_request_pad_simple (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_request_pad_simple (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;
}
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
}