tests/examples/dynamic/: Add example app that dynamically switches between 3 'encoders'.

Original commit message from CVS:
* tests/examples/dynamic/Makefile.am:
* tests/examples/dynamic/codec-select.c: (make_encoder),
(make_pipeline), (do_switch), (my_bus_callback), (main):
Add example app that dynamically switches between 3 'encoders'.

ChangeLog

@@ -1,3 +1,10 @@
+2008-08-01  Wim Taymans  <wim.taymans@collabora.co.uk>
+
+	* tests/examples/dynamic/Makefile.am:
+	* tests/examples/dynamic/codec-select.c: (make_encoder),
+	(make_pipeline), (do_switch), (my_bus_callback), (main):
+	Add example app that dynamically switches between 3 'encoders'.
+
 2008-07-31  Wim Taymans  <wim.taymans@collabora.co.uk>
 
 	* gst/playback/gstplaysink.c: (gst_play_sink_set_vis_plugin):

common

@@ -1 +1 @@
-Subproject commit e79879859bc866545379eb77e1378a906dc30ebf
+Subproject commit d70ca17ae6fbe6020996e4567275d5e14972ed45

tests/examples/dynamic/Makefile.am

@@ -1,5 +1,9 @@
-noinst_PROGRAMS = addstream
+noinst_PROGRAMS = addstream codec-select
 
-addstream_SOURCES = addstream.c
+addstream_SOURCES = addstream.c 
 addstream_CFLAGS = $(GST_CFLAGS) -D_GNU_SOURCE
 addstream_LDFLAGS = $(GST_LIBS)
+
+codec_select_SOURCES = codec-select.c 
+codec_select_CFLAGS = $(GST_CFLAGS) -D_GNU_SOURCE
+codec_select_LDFLAGS = $(GST_LIBS)

tests/examples/dynamic/codec-select.c

@@ -0,0 +1,298 @@
+/* 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;
+}