3 * appsrc-stream.c: example for using appsrc in streaming mode.
5 * Copyright (C) 2008 Wim Taymans <wim.taymans@gmail.com>
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
20 * Boston, MA 02110-1301, USA.
33 GST_DEBUG_CATEGORY (appsrc_playbin_debug);
34 #define GST_CAT_DEFAULT appsrc_playbin_debug
37 * an example application of using appsrc in streaming push mode. We simply push
38 * buffers into appsrc. The size of the buffers we push can be any size we
41 * This example is very close to how one would deal with a streaming webserver
42 * that does not support range requests or does not report the total file size.
44 * Some optimisations are done so that we don't push too much data. We connect
45 * to the need-data and enough-data signals to start/stop sending buffers.
47 * Appsrc in streaming mode (the default) does not support seeking so we don't
48 * have to handle any seek callbacks.
50 * Some formats are able to estimate the duration of the media file based on the
51 * file length (mp3, mpeg,..), others report an unknown length (ogg,..).
53 typedef struct _App App;
71 #define CHUNK_SIZE 4096
73 /* This method is called by the idle GSource in the mainloop. We feed CHUNK_SIZE
75 * The ide handler is added to the mainloop when appsrc requests us to start
76 * sending data (need-data signal) and is removed when appsrc has enough data
77 * (enough-data signal).
86 if (app->offset >= app->length) {
87 /* we are EOS, send end-of-stream and remove the source */
88 g_signal_emit_by_name (app->appsrc, "end-of-stream", &ret);
92 /* read the next chunk */
93 buffer = gst_buffer_new ();
96 if (app->offset + len > app->length)
97 len = app->length - app->offset;
99 gst_buffer_append_memory (buffer,
100 gst_memory_new_wrapped (GST_MEMORY_FLAG_READONLY,
101 app->data, app->length, app->offset, len, NULL, NULL));
103 GST_DEBUG ("feed buffer %p, offset %" G_GUINT64_FORMAT "-%u", buffer,
105 g_signal_emit_by_name (app->appsrc, "push-buffer", buffer, &ret);
106 gst_buffer_unref (buffer);
107 if (ret != GST_FLOW_OK) {
108 /* some error, stop sending data */
117 /* This signal callback is called when appsrc needs data, we add an idle handler
118 * to the mainloop to start pushing data into the appsrc */
120 start_feed (GstElement * playbin, guint size, App * app)
122 if (app->sourceid == 0) {
123 GST_DEBUG ("start feeding");
124 app->sourceid = g_idle_add ((GSourceFunc) read_data, app);
128 /* This callback is called when appsrc has enough data and we can stop sending.
129 * We remove the idle handler from the mainloop */
131 stop_feed (GstElement * playbin, App * app)
133 if (app->sourceid != 0) {
134 GST_DEBUG ("stop feeding");
135 g_source_remove (app->sourceid);
140 /* this callback is called when playbin has constructed a source object to read
141 * from. Since we provided the appsrc:// uri to playbin, this will be the
142 * appsrc that we must handle. We set up some signals to start and stop pushing
143 * data into appsrc */
145 found_source (GObject * object, GObject * orig, GParamSpec * pspec, App * app)
147 /* get a handle to the appsrc */
148 g_object_get (orig, pspec->name, &app->appsrc, NULL);
150 GST_DEBUG ("got appsrc %p", app->appsrc);
152 /* we can set the length in appsrc. This allows some elements to estimate the
153 * total duration of the stream. It's a good idea to set the property when you
154 * can but it's not required. */
155 g_object_set (app->appsrc, "size", (gint64) app->length, NULL);
157 /* configure the appsrc, we will push data into the appsrc from the
159 g_signal_connect (app->appsrc, "need-data", G_CALLBACK (start_feed), app);
160 g_signal_connect (app->appsrc, "enough-data", G_CALLBACK (stop_feed), app);
164 bus_message (GstBus * bus, GstMessage * message, App * app)
166 GST_DEBUG ("got message %s",
167 gst_message_type_get_name (GST_MESSAGE_TYPE (message)));
169 switch (GST_MESSAGE_TYPE (message)) {
170 case GST_MESSAGE_ERROR:
171 g_error ("received error");
172 g_main_loop_quit (app->loop);
174 case GST_MESSAGE_EOS:
175 g_main_loop_quit (app->loop);
184 main (int argc, char *argv[])
187 GError *error = NULL;
190 gst_init (&argc, &argv);
192 GST_DEBUG_CATEGORY_INIT (appsrc_playbin_debug, "appsrc-playbin", 0,
193 "appsrc playbin example");
196 g_print ("usage: %s <filename>\n", argv[0]);
200 /* try to open the file as an mmapped file */
201 app->file = g_mapped_file_new (argv[1], FALSE, &error);
203 g_print ("failed to open file: %s\n", error->message);
204 g_error_free (error);
207 /* get some vitals, this will be used to read data from the mmapped file and
208 * feed it to appsrc. */
209 app->length = g_mapped_file_get_length (app->file);
210 app->data = (guint8 *) g_mapped_file_get_contents (app->file);
213 /* create a mainloop to get messages and to handle the idle handler that will
214 * feed data to appsrc. */
215 app->loop = g_main_loop_new (NULL, TRUE);
217 app->playbin = gst_element_factory_make ("playbin", NULL);
218 g_assert (app->playbin);
220 bus = gst_pipeline_get_bus (GST_PIPELINE (app->playbin));
222 /* add watch for messages */
223 gst_bus_add_watch (bus, (GstBusFunc) bus_message, app);
225 /* set to read from appsrc */
226 g_object_set (app->playbin, "uri", "appsrc://", NULL);
228 /* get notification when the source is created so that we get a handle to it
229 * and can configure it */
230 g_signal_connect (app->playbin, "deep-notify::source",
231 (GCallback) found_source, app);
233 /* go to playing and wait in a mainloop. */
234 gst_element_set_state (app->playbin, GST_STATE_PLAYING);
236 /* this mainloop is stopped when we receive an error or EOS */
237 g_main_loop_run (app->loop);
239 GST_DEBUG ("stopping");
241 gst_element_set_state (app->playbin, GST_STATE_NULL);
244 g_mapped_file_unref (app->file);
246 gst_object_unref (bus);
247 g_main_loop_unref (app->loop);