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* appsrc-stream.c: example for using appsrc in streaming mode.
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* Copyright (C) 2008 Wim Taymans <wim.taymans@gmail.com>
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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GST_DEBUG_CATEGORY (appsrc_playbin_debug);
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#define GST_CAT_DEFAULT appsrc_playbin_debug
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* an example application of using appsrc in streaming push mode. We simply push
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* buffers into appsrc. The size of the buffers we push can be any size we
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* This example is very close to how one would deal with a streaming webserver
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* that does not support range requests or does not report the total file size.
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* Some optimisations are done so that we don't push too much data. We connect
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* to the need-data and enough-data signals to start/stop sending buffers.
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* Appsrc in streaming mode (the default) does not support seeking so we don't
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* have to handle any seek callbacks.
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* Some formats are able to estimate the duration of the media file based on the
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* file length (mp3, mpeg,..), others report an unknown length (ogg,..).
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typedef struct _App App;
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#define CHUNK_SIZE 4096
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/* This method is called by the idle GSource in the mainloop. We feed CHUNK_SIZE
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* The ide handler is added to the mainloop when appsrc requests us to start
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* sending data (need-data signal) and is removed when appsrc has enough data
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* (enough-data signal).
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buffer = gst_buffer_new ();
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if (app->offset >= app->length) {
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/* we are EOS, send end-of-stream and remove the source */
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g_signal_emit_by_name (app->appsrc, "end-of-stream", &ret);
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/* read the next chunk */
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if (app->offset + len > app->length)
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len = app->length - app->offset;
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GST_BUFFER_DATA (buffer) = app->data + app->offset;
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GST_BUFFER_SIZE (buffer) = len;
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GST_DEBUG ("feed buffer %p, offset %" G_GUINT64_FORMAT "-%u", buffer,
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g_signal_emit_by_name (app->appsrc, "push-buffer", buffer, &ret);
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gst_buffer_unref (buffer);
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if (ret != GST_FLOW_OK) {
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/* some error, stop sending data */
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/* This signal callback is called when appsrc needs data, we add an idle handler
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* to the mainloop to start pushing data into the appsrc */
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start_feed (GstElement * playbin, guint size, App * app)
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if (app->sourceid == 0) {
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GST_DEBUG ("start feeding");
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app->sourceid = g_idle_add ((GSourceFunc) read_data, app);
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/* This callback is called when appsrc has enough data and we can stop sending.
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* We remove the idle handler from the mainloop */
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stop_feed (GstElement * playbin, App * app)
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if (app->sourceid != 0) {
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GST_DEBUG ("stop feeding");
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g_source_remove (app->sourceid);
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/* this callback is called when playbin2 has constructed a source object to read
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* from. Since we provided the appsrc:// uri to playbin2, this will be the
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* appsrc that we must handle. We set up some signals to start and stop pushing
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* data into appsrc */
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found_source (GObject * object, GObject * orig, GParamSpec * pspec, App * app)
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/* get a handle to the appsrc */
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g_object_get (orig, pspec->name, &app->appsrc, NULL);
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GST_DEBUG ("got appsrc %p", app->appsrc);
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/* we can set the length in appsrc. This allows some elements to estimate the
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* total duration of the stream. It's a good idea to set the property when you
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* can but it's not required. */
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g_object_set (app->appsrc, "size", app->length, NULL);
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/* configure the appsrc, we will push data into the appsrc from the
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g_signal_connect (app->appsrc, "need-data", G_CALLBACK (start_feed), app);
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g_signal_connect (app->appsrc, "enough-data", G_CALLBACK (stop_feed), app);
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bus_message (GstBus * bus, GstMessage * message, App * app)
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GST_DEBUG ("got message %s",
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gst_message_type_get_name (GST_MESSAGE_TYPE (message)));
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switch (GST_MESSAGE_TYPE (message)) {
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case GST_MESSAGE_ERROR:
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g_error ("received error");
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g_main_loop_quit (app->loop);
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case GST_MESSAGE_EOS:
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g_main_loop_quit (app->loop);
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main (int argc, char *argv[])
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GError *error = NULL;
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gst_init (&argc, &argv);
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GST_DEBUG_CATEGORY_INIT (appsrc_playbin_debug, "appsrc-playbin", 0,
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"appsrc playbin example");
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g_print ("usage: %s <filename>\n", argv[0]);
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/* try to open the file as an mmapped file */
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app->file = g_mapped_file_new (argv[1], FALSE, &error);
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g_print ("failed to open file: %s\n", error->message);
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g_error_free (error);
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/* get some vitals, this will be used to read data from the mmapped file and
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* feed it to appsrc. */
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app->length = g_mapped_file_get_length (app->file);
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app->data = (guint8 *) g_mapped_file_get_contents (app->file);
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/* create a mainloop to get messages and to handle the idle handler that will
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* feed data to appsrc. */
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app->loop = g_main_loop_new (NULL, TRUE);
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app->playbin = gst_element_factory_make ("playbin2", NULL);
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g_assert (app->playbin);
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bus = gst_pipeline_get_bus (GST_PIPELINE (app->playbin));
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/* add watch for messages */
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gst_bus_add_watch (bus, (GstBusFunc) bus_message, app);
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/* set to read from appsrc */
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g_object_set (app->playbin, "uri", "appsrc://", NULL);
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/* get notification when the source is created so that we get a handle to it
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* and can configure it */
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g_signal_connect (app->playbin, "deep-notify::source",
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(GCallback) found_source, app);
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/* go to playing and wait in a mainloop. */
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gst_element_set_state (app->playbin, GST_STATE_PLAYING);
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/* this mainloop is stopped when we receive an error or EOS */
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g_main_loop_run (app->loop);
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GST_DEBUG ("stopping");
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gst_element_set_state (app->playbin, GST_STATE_NULL);
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g_mapped_file_free (app->file);
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gst_object_unref (bus);
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g_main_loop_unref (app->loop);
added
removed
examples/app/appsrc-stream.c
