1 /* GStreamer
2 *
3 * Copyright (C) 2010 Wim Taymans <wim.taymans@collabora.co.uk>
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
14 *
15 * You should have received a copy of the GNU Library General Public
16 * License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
18 * Boston, MA 02110-1301, USA.
19 */
20
21 /* An example of synchronized playback and recording.
22 * The trick is to wait for the playback pipeline to preroll before starting
23 * playback and recording.
24 */
25 #include <string.h>
26
27 #include <gst/gst.h>
28
29 /* Define to run the asynchronous version, which has the benefit that it doesn't
30 * block the main thread but it produces slightly less clear code. */
31 #define ASYNC_VERSION
32
33 static GMainLoop *loop;
34 static GstElement *pipeline = NULL;
35 static GstElement *play_bin, *play_source, *play_sink;
36 static GstElement *rec_bin, *rec_source, *rec_sink;
37
38 static gboolean
message_handler(GstBus * bus,GstMessage * message,gpointer user_data)39 message_handler (GstBus * bus, GstMessage * message, gpointer user_data)
40 {
41
42 switch (GST_MESSAGE_TYPE (message)) {
43 #ifdef ASYNC_VERSION
44 case GST_MESSAGE_ELEMENT:{
45 const GstStructure *str;
46
47 str = gst_message_get_structure (message);
48
49 if (gst_structure_has_name (str, "GstBinForwarded")) {
50 GstMessage *orig;
51
52 /* unwrap the element message */
53 gst_structure_get (str, "message", GST_TYPE_MESSAGE, &orig, NULL);
54 g_assert (orig);
55
56 switch (GST_MESSAGE_TYPE (orig)) {
57 case GST_MESSAGE_ASYNC_DONE:
58 g_print ("ASYNC done %s\n", GST_MESSAGE_SRC_NAME (orig));
59 if (GST_MESSAGE_SRC (orig) == GST_OBJECT_CAST (play_bin)) {
60 g_print
61 ("prerolled, starting synchronized playback and recording\n");
62 /* returns ASYNC because the sink linked to the live source is not
63 * prerolled */
64 if (gst_element_set_state (pipeline,
65 GST_STATE_PLAYING) != GST_STATE_CHANGE_ASYNC) {
66 g_warning ("State change failed");
67 }
68 }
69 break;
70 default:
71 break;
72 }
73 }
74 break;
75 }
76 #endif
77 case GST_MESSAGE_EOS:
78 g_print ("EOS\n");
79 g_main_loop_quit (loop);
80 break;
81 case GST_MESSAGE_ERROR:{
82 GError *err = NULL;
83
84 gst_message_parse_error (message, &err, NULL);
85 g_print ("error: %s\n", err->message);
86 g_clear_error (&err);
87
88 g_main_loop_quit (loop);
89 break;
90 }
91 default:
92 break;
93 }
94
95 return TRUE;
96 }
97
98 int
main(int argc,char * argv[])99 main (int argc, char *argv[])
100 {
101 GstBus *bus;
102 gint watch_id;
103
104 gst_init (NULL, NULL);
105
106 loop = g_main_loop_new (NULL, TRUE);
107
108 pipeline = gst_pipeline_new ("pipeline");
109 #ifdef ASYNC_VERSION
110 /* this enables messages of individual elements inside the pipeline */
111 g_object_set (pipeline, "message-forward", TRUE, NULL);
112 #endif
113
114 /* make a bin with the playback elements this is a non-live pipeline */
115 play_bin = gst_bin_new ("play_bin");
116 play_source = gst_element_factory_make ("audiotestsrc", "play_source");
117 play_sink = gst_element_factory_make ("autoaudiosink", "play_sink");
118
119 gst_bin_add (GST_BIN (play_bin), play_source);
120 gst_bin_add (GST_BIN (play_bin), play_sink);
121
122 gst_element_link (play_source, play_sink);
123
124 /* make bin with the record elements, this is a live pipeline */
125 rec_bin = gst_bin_new ("rec_bin");
126 rec_source = gst_element_factory_make ("autoaudiosrc", "rec_source");
127 rec_sink = gst_element_factory_make ("fakesink", "rec_sink");
128
129 gst_bin_add (GST_BIN (rec_bin), rec_source);
130 gst_bin_add (GST_BIN (rec_bin), rec_sink);
131
132 gst_element_link (rec_source, rec_sink);
133
134 gst_bin_add (GST_BIN (pipeline), play_bin);
135 gst_bin_add (GST_BIN (pipeline), rec_bin);
136
137 bus = gst_element_get_bus (pipeline);
138 watch_id = gst_bus_add_watch (bus, message_handler, NULL);
139 gst_object_unref (bus);
140
141 g_print ("going to PAUSED\n");
142 /* returns NO_PREROLL because we have a live element */
143 if (gst_element_set_state (pipeline,
144 GST_STATE_PAUSED) != GST_STATE_CHANGE_NO_PREROLL) {
145 g_warning ("Expected state change NO_PREROLL result");
146 }
147
148 g_print ("waiting for playback preroll\n");
149 #ifndef ASYNC_VERSION
150 /* sync wait for preroll on the playback bin and then go to PLAYING */
151 if (gst_element_get_state (play_bin, NULL, NULL,
152 GST_CLOCK_TIME_NONE) != GST_STATE_CHANGE_SUCCESS) {
153 g_warning ("Error while waiting for state change");
154 }
155 g_print ("prerolled, starting synchronized playback and recording\n");
156 /* returns ASYNC because the sink linked to the live source is not
157 * prerolled */
158 if (gst_element_set_state (pipeline,
159 GST_STATE_PLAYING) != GST_STATE_CHANGE_ASYNC) {
160 g_warning ("Expected state change NO_PREROLL result");
161 }
162 #endif
163
164 g_main_loop_run (loop);
165
166 g_source_remove (watch_id);
167 gst_element_set_state (pipeline, GST_STATE_NULL);
168 gst_object_unref (pipeline);
169
170 g_main_loop_unref (loop);
171
172 return 0;
173 }
174