audiomix: add a simple audiomix example

tests/examples/audio/.gitignore

@@ -1 +1,3 @@
+audiomix
 testchannels
+

tests/examples/audio/Makefile.am

@@ -5,3 +5,9 @@ testchannels_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_CFLAGS)
 testchannels_LDADD = $(top_builddir)/gst-libs/gst/audio/libgstaudio-$(GST_MAJORMINOR).la \
                      $(GST_LIBS)
 
+if HAVE_GTK
+noinst_PROGRAMS = audiomix
+audiomix_SOURCES = audiomix.c
+audiomix_CFLAGS = $(GST_CFLAGS) $(GTK_CFLAGS) -D_GNU_SOURCE
+audiomix_LDADD = $(GST_LIBS) $(GTK_LIBS) $(LIBM)
+endif

tests/examples/audio/audiomix.c

@@ -0,0 +1,210 @@
+/* GStreamer
+ *
+ * audiomix.c: sample audio mixing application
+ *
+ * Copyright (C) 2011 Stefan Sauer <ensonic@users.sf.net>
+ *
+ * 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <string.h>
+#include <gst/gst.h>
+#include <gtk/gtk.h>
+
+/* global items for the interaction */
+static GtkWidget *scale;
+static GObject *volumes[2];
+static gint num_vol = 0;
+
+
+static void
+value_changed_callback (GtkWidget * widget, gpointer * user_data)
+{
+  gdouble value = gtk_range_get_value (GTK_RANGE (widget));
+  g_object_set (volumes[0], "volume", 1.0 - value, NULL);
+  g_object_set (volumes[1], "volume", value, NULL);
+}
+
+static void
+setup_gui (GstElement * volume, gchar * file_name1, gchar * file_name2)
+{
+  GtkWidget *window, *layout, *label;
+  gchar *name, *ext;
+
+  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+  gtk_window_set_title (GTK_WINDOW (window), "audiomix");
+  g_signal_connect (window, "destroy", gtk_main_quit, NULL);
+
+  layout = gtk_table_new (2, 3, FALSE);
+  gtk_table_set_col_spacings (GTK_TABLE (layout), 6);
+  gtk_container_add (GTK_CONTAINER (window), layout);
+
+  /* channel labels */
+  name = g_path_get_basename (file_name1);
+  if ((ext = strrchr (name, '.')))
+    *ext = '\0';
+  label = gtk_label_new (name);
+  g_free (name);
+  gtk_misc_set_alignment (GTK_MISC (label), 0.0, 0.5);
+  gtk_table_attach_defaults (GTK_TABLE (layout), label, 0, 1, 0, 1);
+
+  gtk_table_attach_defaults (GTK_TABLE (layout), gtk_label_new ("|"), 1, 2, 0,
+      1);
+
+  name = g_path_get_basename (file_name2);
+  if ((ext = strrchr (name, '.')))
+    *ext = '\0';
+  label = gtk_label_new (name);
+  g_free (name);
+  gtk_misc_set_alignment (GTK_MISC (label), 1.0, 0.5);
+  gtk_table_attach_defaults (GTK_TABLE (layout), label, 2, 3, 0, 1);
+
+  /* mix slider */
+  scale = gtk_hscale_new_with_range (0.0, 1.0, 1.0 / 200.0);
+  gtk_range_set_value (GTK_RANGE (scale), 0.0);
+  gtk_widget_set_size_request (scale, 200, -1);
+  gtk_table_attach_defaults (GTK_TABLE (layout), scale, 0, 3, 1, 2);
+  g_signal_connect (scale, "value-changed",
+      G_CALLBACK (value_changed_callback), volume);
+
+  gtk_widget_show_all (GTK_WIDGET (window));
+}
+
+static void
+message_received (GstBus * bus, GstMessage * message, GstPipeline * pipeline)
+{
+  const GstStructure *s;
+
+  s = gst_message_get_structure (message);
+  g_print ("message from \"%s\" (%s): ",
+      GST_STR_NULL (GST_ELEMENT_NAME (GST_MESSAGE_SRC (message))),
+      gst_message_type_get_name (GST_MESSAGE_TYPE (message)));
+  if (s) {
+    gchar *sstr;
+
+    sstr = gst_structure_to_string (s);
+    g_print ("%s\n", sstr);
+    g_free (sstr);
+  } else {
+    g_print ("no message details\n");
+  }
+}
+
+static void
+eos_message_received (GstBus * bus, GstMessage * message,
+    GstPipeline * pipeline)
+{
+  message_received (bus, message, pipeline);
+  gtk_main_quit ();
+}
+
+static void
+dynamic_link (GstPadTemplate * templ, GstPad * newpad, gpointer user_data)
+{
+  GstPad *target = GST_PAD (user_data);
+
+  gst_pad_link (newpad, target);
+  gst_object_unref (target);
+}
+
+static void
+make_mixer_channel (GstElement * pipeline, GstElement * mix, gchar * file_name)
+{
+  GstElement *filesrc, *decodebin, *volume, *convert, *format;
+  GstCaps *caps;
+
+  /* prepare mixer channel */
+  filesrc = gst_element_factory_make ("filesrc", NULL);
+  decodebin = gst_element_factory_make ("decodebin2", NULL);
+  volume = gst_element_factory_make ("volume", NULL);
+  convert = gst_element_factory_make ("audioconvert", NULL);
+  format = gst_element_factory_make ("capsfilter", NULL);
+  gst_bin_add_many (GST_BIN (pipeline), filesrc, decodebin, volume, convert,
+      format, NULL);
+  gst_element_link (filesrc, decodebin);
+  gst_element_link_many (volume, convert, format, mix, NULL);
+
+  /* configure elements */
+  g_object_set (filesrc, "location", file_name, NULL);
+  g_object_set (volume, "volume", (num_vol == 0) ? 1.0 : 0.0, NULL);
+
+  caps = gst_caps_from_string ("audio/x-raw-int, "
+      "channels = (int) 2, "
+      "endianness = (int) BYTE_ORDER, "
+      "width = (int) 16, " "depth = (int) 16, " "signed = (boolean) true");
+  g_object_set (format, "caps", caps, NULL);
+  gst_caps_unref (caps);
+
+  /* remember volume element */
+  volumes[num_vol++] = (GObject *) volume;
+
+  /* handle dynamic pads */
+  g_signal_connect (G_OBJECT (decodebin), "pad-added",
+      G_CALLBACK (dynamic_link), gst_element_get_static_pad (volume, "sink"));
+}
+
+int
+main (int argc, char *argv[])
+{
+  GstElement *pipeline = NULL;
+  GstElement *mix, *convert, *sink;
+  GstBus *bus;
+
+  if (argc < 3) {
+    g_print ("Usage: audiomix <file1> <file2>\n");
+    return 1;
+  }
+
+  gst_init (&argc, &argv);
+  gtk_init (&argc, &argv);
+
+  /* prepare tail of pipeline */
+  pipeline = gst_pipeline_new ("audiomix");
+  mix = gst_element_factory_make ("adder", NULL);
+  convert = gst_element_factory_make ("audioconvert", NULL);
+  sink = gst_element_factory_make ("autoaudiosink", NULL);
+  gst_bin_add_many (GST_BIN (pipeline), mix, convert, sink, NULL);
+  gst_element_link_many (mix, convert, sink, NULL);
+
+  /* prepare mixer channel strips */
+  make_mixer_channel (pipeline, mix, argv[1]);
+  make_mixer_channel (pipeline, mix, argv[2]);
+
+  /* setup message handling */
+  bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
+  gst_bus_add_signal_watch_full (bus, G_PRIORITY_HIGH);
+  g_signal_connect (bus, "message::error", (GCallback) message_received,
+      pipeline);
+  g_signal_connect (bus, "message::warning", (GCallback) message_received,
+      pipeline);
+  g_signal_connect (bus, "message::eos", (GCallback) eos_message_received,
+      pipeline);
+
+  /* setup GUI */
+  setup_gui (pipeline, argv[1], argv[2]);
+
+  /* go to main loop */
+  gst_element_set_state (pipeline, GST_STATE_PLAYING);
+  gtk_main ();
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  gst_object_unref (pipeline);
+
+  return 0;
+}