+/* GStreamer
+ *
+ * codec-select.c: sample application to dynamically select a codec
+ *
+ * Copyright (C) <2008> Wim Taymans <wim dot taymans at gmail dot com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+/*
+ * This example sets up a pipeline to 'encode' an audiotestsrc into 3 different
+ * formats. The format can be selected dynamically at runtime.
+ *
+ * Each of the encoders require the audio in a specific different format.
+ *
+ * This example uses identity as the encoder and enforces the caps on identity
+ * with a capsfilter.
+ *
+ * This is a good example of input and output selector and how these elements
+ * preserve segment and timing information while switching between streams.
+ */
+
+#include <string.h>
+#include <gst/gst.h>
+
+/* Create an encoder element.
+ * We make a bin containing:
+ *
+ * audioresample ! <enccaps> ! identity
+ *
+ * The sinkpad of audioresample and source pad of identity are ghosted on the
+ * bin.
+ */
+static GstElement *
+make_encoder (const GstCaps * caps)
+{
+ GstElement *result;
+ GstElement *audioresample;
+ GstElement *capsfilter;
+ GstElement *identity;
+ GstPad *pad;
+
+ /* create result bin */
+ result = gst_bin_new (NULL);
+ g_assert (result);
+
+ /* create elements */
+ audioresample = gst_element_factory_make ("audioresample", NULL);
+ g_assert (audioresample);
+
+ capsfilter = gst_element_factory_make ("capsfilter", NULL);
+ g_assert (capsfilter);
+ g_object_set (capsfilter, "caps", caps, NULL);
+
+ identity = gst_element_factory_make ("identity", NULL);
+ g_assert (identity);
+ g_object_set (identity, "silent", TRUE, NULL);
+
+ /* add elements to result bin */
+ gst_bin_add (GST_BIN (result), audioresample);
+ gst_bin_add (GST_BIN (result), capsfilter);
+ gst_bin_add (GST_BIN (result), identity);
+
+ /* link elements */
+ gst_element_link_pads (audioresample, "src", capsfilter, "sink");
+ gst_element_link_pads (capsfilter, "src", identity, "sink");
+
+ /* ghost src and sink pads */
+ pad = gst_element_get_static_pad (audioresample, "sink");
+ gst_element_add_pad (result, gst_ghost_pad_new ("sink", pad));
+ gst_object_unref (pad);
+
+ pad = gst_element_get_static_pad (identity, "src");
+ gst_element_add_pad (result, gst_ghost_pad_new ("src", pad));
+ gst_object_unref (pad);
+
+ return result;
+}
+
+/*
+ * We generate:
+ *
+ * audiotestsrc ! <audiocaps> ! output-selector ! [enc1 .. enc3] ! input-selector
+ * select-all = true ! fakesink
+ *
+ * <audiocaps> makes sure we only produce one format from the audiotestsrc.
+ *
+ * Each encX element consists of:
+ *
+ * audioresample ! <enccaps> ! identity !
+ *
+ * This way we can simply switch encoders without having to renegotiate.
+ */
+static GstElement *
+make_pipeline (void)
+{
+ GstElement *result;
+ GstElement *audiotestsrc;
+ GstElement *audiocaps;
+ GstElement *outputselect;
+ GstElement *inputselect;
+ GstElement *sink;
+ GstCaps *caps;
+ GstCaps *capslist[3];
+ gint i;
+
+ /* create result pipeline */
+ result = gst_pipeline_new (NULL);
+ g_assert (result);
+
+ /* create various elements */
+ audiotestsrc = gst_element_factory_make ("audiotestsrc", NULL);
+ g_object_set (audiotestsrc, "num-buffers", 1000, NULL);
+ g_assert (audiotestsrc);
+
+ audiocaps = gst_element_factory_make ("capsfilter", NULL);
+ g_assert (audiocaps);
+
+ caps =
+ gst_caps_from_string
+ ("audio/x-raw-int,signed=true,width=16,depth=16,rate=48000,channels=1");
+ g_object_set (audiocaps, "caps", caps, NULL);
+ gst_caps_unref (caps);
+
+ outputselect = gst_element_factory_make ("output-selector", "select");
+ g_assert (outputselect);
+
+ inputselect = gst_element_factory_make ("input-selector", NULL);
+ g_assert (inputselect);
+ g_object_set (inputselect, "select-all", TRUE, NULL);
+
+ sink = gst_element_factory_make ("fakesink", NULL);
+ g_object_set (sink, "sync", TRUE, NULL);
+ g_object_set (sink, "silent", TRUE, NULL);
+ g_assert (sink);
+
+ /* add elements */
+ gst_bin_add (GST_BIN (result), audiotestsrc);
+ gst_bin_add (GST_BIN (result), audiocaps);
+ gst_bin_add (GST_BIN (result), outputselect);
+ gst_bin_add (GST_BIN (result), inputselect);
+ gst_bin_add (GST_BIN (result), sink);
+
+ /* link elements */
+ gst_element_link_pads (audiotestsrc, "src", audiocaps, "sink");
+ gst_element_link_pads (audiocaps, "src", outputselect, "sink");
+ gst_element_link_pads (inputselect, "src", sink, "sink");
+
+ /* make caps */
+ capslist[0] =
+ gst_caps_from_string
+ ("audio/x-raw-int,signed=true,width=16,depth=16,rate=48000,channels=1");
+ capslist[1] =
+ gst_caps_from_string
+ ("audio/x-raw-int,signed=true,width=16,depth=16,rate=16000,channels=1");
+ capslist[2] =
+ gst_caps_from_string
+ ("audio/x-raw-int,signed=true,width=16,depth=16,rate=8000,channels=1");
+
+ /* create encoder elements */
+ for (i = 0; i < 3; i++) {
+ GstElement *encoder;
+ GstPad *srcpad, *sinkpad;
+
+ encoder = make_encoder (capslist[i]);
+ g_assert (encoder);
+
+ gst_bin_add (GST_BIN (result), encoder);
+
+ srcpad = gst_element_get_request_pad (outputselect, "src%d");
+ sinkpad = gst_element_get_static_pad (encoder, "sink");
+ gst_pad_link (srcpad, sinkpad);
+ gst_object_unref (srcpad);
+ gst_object_unref (sinkpad);
+
+ srcpad = gst_element_get_static_pad (encoder, "src");
+ sinkpad = gst_element_get_request_pad (inputselect, "sink%d");
+ gst_pad_link (srcpad, sinkpad);
+ gst_object_unref (srcpad);
+ gst_object_unref (sinkpad);
+ }
+
+ return result;
+}
+
+static gboolean
+do_switch (GstElement * pipeline)
+{
+ gint rand;
+ GstElement *select;
+ gchar *name;
+ GstPad *pad;
+
+ rand = g_random_int_range (0, 3);
+
+ g_print ("switching to %d\n", rand);
+
+ /* find the selector */
+ select = gst_bin_get_by_name (GST_BIN (pipeline), "select");
+
+ /* get the named pad */
+ name = g_strdup_printf ("src%d", rand);
+ pad = gst_element_get_static_pad (select, name);
+ g_free (name);
+
+ /* set the active pad */
+ g_object_set (select, "active-pad", pad, NULL);
+
+ return TRUE;
+}
+
+static gboolean
+my_bus_callback (GstBus * bus, GstMessage * message, gpointer data)
+{
+ GstElement *sender = (GstElement *) GST_MESSAGE_SRC (message);
+ const gchar *name = gst_element_get_name (sender);
+ GMainLoop *loop = (GMainLoop *) data;
+
+ g_print ("Got %s message from %s\n", GST_MESSAGE_TYPE_NAME (message), name);
+
+ switch (GST_MESSAGE_TYPE (message)) {
+
+ case GST_MESSAGE_ERROR:{
+ GError *err;
+ gchar *debug;
+
+ gst_message_parse_error (message, &err, &debug);
+ g_print ("Error: %s (%s)\n", err->message, debug);
+ 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;
+ }
+
+ return TRUE;
+}
+
+gint
+main (gint argc, gchar * argv[])
+{
+ GstElement *pipeline;
+ GstBus *bus;
+ GMainLoop *loop;
+
+ /* init GStreamer */
+ gst_init (&argc, &argv);
+ loop = g_main_loop_new (NULL, FALSE);
+
+ /* set up */
+ pipeline = make_pipeline ();
+
+ g_signal_connect (pipeline, "deep_notify",
+ G_CALLBACK (gst_object_default_deep_notify), NULL);
+
+ bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
+ gst_bus_add_watch (bus, my_bus_callback, loop);
+ gst_object_unref (bus);
+
+ g_print ("Starting pipeline\n");
+
+ gst_element_set_state (pipeline, GST_STATE_PLAYING);
+
+ /* add a timeout to cycle between the formats */
+ g_timeout_add (1000, (GSourceFunc) do_switch, pipeline);
+
+ /* now run */
+ g_main_loop_run (loop);
+
+ g_print ("Nulling pipeline\n");
+
+ /* also clean up */
+ gst_element_set_state (pipeline, GST_STATE_NULL);
+ gst_object_unref (pipeline);
+
+ return 0;
+}
projects / mafwsubrenderer / blobdiff