Tiendo a utilizar selector de salida o selector de entrada bins dependiendo de la situación en lugar de la complejidad de bloqueo de bloc (he respondido el bloqueo de bloc en otra publicación http://gstreamer-devel.966125.n4.nabble.com/Dynamically-adding-and-removing-branches-of-a-tee-td973635.html#a4656812). Y conecte el selector a los contenedores fakesrc o fakesink cuando no esté en uso. En el ejemplo siguiente si uno está utilizando GTK, entonces uno puede reemplazar la línea g_timeout_add (SWITCH_TIMEOUT, switch_cb, osel); con gtk_toggle_button y poner todo el código actualmente en la función switch_cb en la función de devolución de llamada del botón de alternar. En este código uno puede cambiar entre los dos enlaces de imagen. Reemplazaría un receptor de imagen con fakesink para mantener la tubería en funcionamiento, en caso de que desee agregar un tee en el futuro con un archivo donde quiero grabar video y ofrecer al reproductor una opción para encender (selector en imágenes)/apagado (selector en fakesink) la pantalla. Esto permite agregar/eliminar contenedores en tiempo de ejecución usando el selector.
#include <gst/gst.h>
#define SWITCH_TIMEOUT 1000
#define NUM_VIDEO_BUFFERS 500
static GMainLoop *loop;
/* Output selector src pads */
static GstPad *osel_src1 = NULL;
static GstPad *osel_src2 = NULL;
static gboolean
my_bus_callback (GstBus * bus, GstMessage * message, gpointer data)
{
g_print ("Got %s message\n", GST_MESSAGE_TYPE_NAME (message));
switch (GST_MESSAGE_TYPE (message)) {
case GST_MESSAGE_ERROR:{
GError *err;
gchar *debug;
gst_message_parse_error (message, &err, &debug);
g_print ("Error: %s\n", err->message);
g_error_free (err);
g_free (debug);
g_main_loop_quit (loop);
break;
}
case GST_MESSAGE_EOS:
/* end-of-stream */
g_main_loop_quit (loop);
break;
default:
/* unhandled message */
break;
}
/* we want to be notified again the next time there is a message
* on the bus, so returning TRUE (FALSE means we want to stop watching
* for messages on the bus and our callback should not be called again)
*/
return TRUE;
}
static gboolean
switch_cb (gpointer user_data)
{
GstElement *sel = GST_ELEMENT (user_data);
GstPad *old_pad, *new_pad = NULL;
g_object_get (G_OBJECT (sel), "active-pad", &old_pad, NULL);
if (old_pad == osel_src1)
new_pad = osel_src2;
else
new_pad = osel_src1;
g_object_set (G_OBJECT (sel), "active-pad", new_pad, NULL);
g_print ("switched from %s:%s to %s:%s\n", GST_DEBUG_PAD_NAME (old_pad),
GST_DEBUG_PAD_NAME (new_pad));
gst_object_unref (old_pad);
return TRUE;
}
gint
main (gint argc, gchar * argv[])
{
GstElement *pipeline, *src, *toverlay, *osel, *sink1, *sink2, *convert;
GstPad *sinkpad1;
GstPad *sinkpad2;
GstBus *bus;
/* init GStreamer */
gst_init (&argc, &argv);
loop = g_main_loop_new (NULL, FALSE);
/* create elements */
pipeline = gst_element_factory_make ("pipeline", "pipeline");
src = gst_element_factory_make ("videotestsrc", "src");
toverlay = gst_element_factory_make ("timeoverlay", "timeoverlay");
osel = gst_element_factory_make ("output-selector", "osel");
convert = gst_element_factory_make ("ffmpegcolorspace", "convert");
sink1 = gst_element_factory_make ("xvimagesink", "sink1");
sink2 = gst_element_factory_make ("ximagesink", "sink2");
if (!pipeline || !src || !toverlay || !osel || !convert || !sink1 || !sink2) {
g_print ("missing element\n");
return -1;
}
/* add them to bin */
gst_bin_add_many (GST_BIN (pipeline), src, toverlay, osel, convert, sink1,
sink2, NULL);
/* set properties */
g_object_set (G_OBJECT (src), "is-live", TRUE, NULL);
g_object_set (G_OBJECT (src), "do-timestamp", TRUE, NULL);
g_object_set (G_OBJECT (src), "num-buffers", NUM_VIDEO_BUFFERS, NULL);
g_object_set (G_OBJECT (sink1), "sync", FALSE, "async", FALSE, NULL);
g_object_set (G_OBJECT (sink2), "sync", FALSE, "async", FALSE, NULL);
g_object_set (G_OBJECT (osel), "resend-latest", TRUE, NULL);
/* link src ! timeoverlay ! osel */
if (!gst_element_link_many (src, toverlay, osel, NULL)) {
g_print ("linking failed\n");
return -1;
}
/* link output 1 */
sinkpad1 = gst_element_get_static_pad (sink1, "sink");
osel_src1 = gst_element_get_request_pad (osel, "src%d");
if (gst_pad_link (osel_src1, sinkpad1) != GST_PAD_LINK_OK) {
g_print ("linking output 1 failed\n");
return -1;
}
gst_object_unref (sinkpad1);
/* link output 2 */
sinkpad2 = gst_element_get_static_pad (convert, "sink");
osel_src2 = gst_element_get_request_pad (osel, "src%d");
if (gst_pad_link (osel_src2, sinkpad2) != GST_PAD_LINK_OK) {
g_print ("linking output 2 failed\n");
return -1;
}
gst_object_unref (sinkpad2);
if (!gst_element_link (convert, sink2)) {
g_print ("linking output 2 failed\n");
return -1;
}
/* add switch callback */
g_timeout_add (SWITCH_TIMEOUT, switch_cb, osel);
/* change to playing */
bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
gst_bus_add_watch (bus, my_bus_callback, loop);
gst_object_unref (bus);
gst_element_set_state (pipeline, GST_STATE_PLAYING);
/* now run */
g_main_loop_run (loop);
/* also clean up */
gst_element_set_state (pipeline, GST_STATE_NULL);
gst_element_release_request_pad (osel, osel_src1);
gst_element_release_request_pad (osel, osel_src2);
gst_object_unref (GST_OBJECT (pipeline));
return 0;
}
otros enlaces: http://cgit.freedesktop.org/gstreamer/gstreamer/tree/docs/design/part-block.txt http: // CGIT .freedesktop.org/gstreamer/gstreamer/tree/docs/design/part-segments.txt – gue