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124 lines
3.5 KiB
C
124 lines
3.5 KiB
C
/* GStreamer
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*
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* demo.c: sample application to change the volume of a pipeline
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*
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* Copyright (C) <2004> Thomas Vander Stichele <thomas at apestaart dot org>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <math.h>
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#include <gst/gst.h>
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#include <gtk/gtk.h>
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/* global pointer for the scale widget */
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GtkWidget *elapsed;
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GtkWidget *scale;
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#ifndef M_LN10
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#define M_LN10 (log(10.0))
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#endif
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static void
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value_changed_callback (GtkWidget * widget, GstElement * volume)
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{
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gdouble value;
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gdouble level;
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value = gtk_range_get_value (GTK_RANGE (widget));
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level = exp (value / 20.0 * M_LN10);
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g_print ("Value: %f dB, level: %f\n", value, level);
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g_object_set (volume, "volume", level, NULL);
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}
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static void
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setup_gui (GstElement * volume)
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{
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GtkWidget *window;
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GtkWidget *vbox;
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GtkWidget *label, *hbox;
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window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
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g_signal_connect (window, "destroy", gtk_main_quit, NULL);
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vbox = gtk_vbox_new (TRUE, 0);
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gtk_container_add (GTK_CONTAINER (window), vbox);
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/* elapsed widget */
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hbox = gtk_hbox_new (TRUE, 0);
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label = gtk_label_new ("Elapsed");
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elapsed = gtk_label_new ("0.000");
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gtk_container_add (GTK_CONTAINER (hbox), label);
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gtk_container_add (GTK_CONTAINER (hbox), elapsed);
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gtk_container_add (GTK_CONTAINER (vbox), hbox);
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/* volume */
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hbox = gtk_hbox_new (TRUE, 0);
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label = gtk_label_new ("volume");
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gtk_container_add (GTK_CONTAINER (hbox), label);
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scale = gtk_hscale_new_with_range (-90.0, 10.0, 0.2);
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gtk_range_set_value (GTK_RANGE (scale), 0.0);
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gtk_widget_set_size_request (scale, 100, -1);
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gtk_container_add (GTK_CONTAINER (hbox), scale);
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gtk_container_add (GTK_CONTAINER (vbox), hbox);
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g_signal_connect (scale, "value-changed",
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G_CALLBACK (value_changed_callback), volume);
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gtk_widget_show_all (GTK_WIDGET (window));
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}
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int
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main (int argc, char *argv[])
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{
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GstElement *pipeline = NULL;
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GError *error = NULL;
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GstElement *volume;
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gst_init (&argc, &argv);
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gtk_init (&argc, &argv);
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pipeline = gst_parse_launchv ((const gchar **) &argv[1], &error);
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if (error) {
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g_print ("pipeline could not be constructed: %s\n", error->message);
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g_print ("Please give a complete pipeline with a 'volume' element.\n");
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g_print ("Example: audiotestsrc ! volume ! %s\n", DEFAULT_AUDIOSINK);
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g_error_free (error);
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return 1;
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}
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volume = gst_bin_get_by_name (GST_BIN (pipeline), "volume0");
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if (volume == NULL) {
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g_print ("Please give a pipeline with a 'volume' element in it\n");
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return 1;
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}
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/* setup GUI */
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setup_gui (volume);
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/* go to main loop */
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gst_element_set_state (pipeline, GST_STATE_PLAYING);
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gst_bus_poll (gst_element_get_bus (pipeline),
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GST_MESSAGE_EOS | GST_MESSAGE_ERROR, -1);
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gst_element_set_state (pipeline, GST_STATE_NULL);
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return 0;
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}
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