3 * appsrc-stream2.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., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, 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 pull mode. When the
38 * appsrc request data with the need-data signal, we retrieve a buffer of an
39 * arbitrary size and push it to appsrc.
41 * This example keeps the internal buffer queue of appsrc to a minimal size,
42 * only feeding data to appsrc when needed.
44 * This is a good example how one would deal with a live resource, such as a udp
45 * socket where one would feed the most recently acquired buffer to appsrc.
47 * Usually one would timestamp the buffers with the running_time of the
48 * pipeline or configure the appsrc to do timestamping by setting the
49 * do-timestamp property to TRUE.
51 * Appsrc in streaming mode (the default) does not support seeking so we don't
52 * have to handle any seek callbacks.
54 * Some formats are able to estimate the duration of the media file based on the
55 * file length (mp3, mpeg,..), others report an unknown length (ogg,..).
57 typedef struct _App App;
74 #define CHUNK_SIZE 4096
76 /* This method is called by the need-data signal callback, we feed data into the
80 feed_data (GstElement * appsrc, guint size, App * app)
86 buffer = gst_buffer_new ();
88 if (app->offset >= app->length) {
89 /* we are EOS, send end-of-stream */
90 g_signal_emit_by_name (app->appsrc, "end-of-stream", &ret);
94 /* read the next chunk */
96 if (app->offset + len > app->length)
97 len = app->length - app->offset;
99 GST_BUFFER_DATA (buffer) = app->data + app->offset;
100 GST_BUFFER_SIZE (buffer) = len;
102 GST_DEBUG ("feed buffer %p, offset %" G_GUINT64_FORMAT "-%u", buffer,
104 g_signal_emit_by_name (app->appsrc, "push-buffer", buffer, &ret);
105 gst_buffer_unref (buffer);
112 /* this callback is called when playbin2 has constructed a source object to read
113 * from. Since we provided the appsrc:// uri to playbin2, this will be the
114 * appsrc that we must handle. We set up a signals to push data into appsrc. */
116 found_source (GObject * object, GObject * orig, GParamSpec * pspec, App * app)
118 /* get a handle to the appsrc */
119 g_object_get (orig, pspec->name, &app->appsrc, NULL);
121 GST_DEBUG ("got appsrc %p", app->appsrc);
123 /* we can set the length in appsrc. This allows some elements to estimate the
124 * total duration of the stream. It's a good idea to set the property when you
125 * can but it's not required. */
126 g_object_set (app->appsrc, "size", (gint64) app->length, NULL);
128 /* configure the appsrc, we will push a buffer to appsrc when it needs more
130 g_signal_connect (app->appsrc, "need-data", G_CALLBACK (feed_data), app);
134 bus_message (GstBus * bus, GstMessage * message, App * app)
136 GST_DEBUG ("got message %s",
137 gst_message_type_get_name (GST_MESSAGE_TYPE (message)));
139 switch (GST_MESSAGE_TYPE (message)) {
140 case GST_MESSAGE_ERROR:
141 g_error ("received error");
142 g_main_loop_quit (app->loop);
144 case GST_MESSAGE_EOS:
145 g_main_loop_quit (app->loop);
154 main (int argc, char *argv[])
157 GError *error = NULL;
160 gst_init (&argc, &argv);
162 GST_DEBUG_CATEGORY_INIT (appsrc_playbin_debug, "appsrc-playbin", 0,
163 "appsrc playbin example");
166 g_print ("usage: %s <filename>\n", argv[0]);
170 /* try to open the file as an mmapped file */
171 app->file = g_mapped_file_new (argv[1], FALSE, &error);
173 g_print ("failed to open file: %s\n", error->message);
174 g_error_free (error);
177 /* get some vitals, this will be used to read data from the mmapped file and
178 * feed it to appsrc. */
179 app->length = g_mapped_file_get_length (app->file);
180 app->data = (guint8 *) g_mapped_file_get_contents (app->file);
183 /* create a mainloop to get messages */
184 app->loop = g_main_loop_new (NULL, TRUE);
186 app->playbin = gst_element_factory_make ("playbin2", NULL);
187 g_assert (app->playbin);
189 bus = gst_pipeline_get_bus (GST_PIPELINE (app->playbin));
191 /* add watch for messages */
192 gst_bus_add_watch (bus, (GstBusFunc) bus_message, app);
194 /* set to read from appsrc */
195 g_object_set (app->playbin, "uri", "appsrc://", NULL);
197 /* get notification when the source is created so that we get a handle to it
198 * and can configure it */
199 g_signal_connect (app->playbin, "deep-notify::source",
200 (GCallback) found_source, app);
202 /* go to playing and wait in a mainloop. */
203 gst_element_set_state (app->playbin, GST_STATE_PLAYING);
205 /* this mainloop is stopped when we receive an error or EOS */
206 g_main_loop_run (app->loop);
208 GST_DEBUG ("stopping");
210 gst_element_set_state (app->playbin, GST_STATE_NULL);
213 g_mapped_file_unref (app->file);
215 gst_object_unref (bus);
216 g_main_loop_unref (app->loop);