examples: v4l2: add example for v4l2src renegotiation

Based on work from Thiago Santos <thiagoss@osg.samsung.com>

https://bugzilla.gnome.org/show_bug.cgi?id=682770

tests/examples/v4l2/Makefile.am

@@ -1,5 +1,9 @@
-noinst_PROGRAMS = camctrl
+noinst_PROGRAMS = camctrl v4l2src-renegotiate
 
 camctrl_SOURCES = camctrl.c
 camctrl_CFLAGS  = $(GST_BASE_CFLAGS) $(GST_CONTROLLER_CFLAGS) $(GST_CFLAGS)
 camctrl_LDADD = $(GST_BASE_LIBS) $(GST_CONTROLLER_LIBS) $(GST_LIBS)
+
+v4l2src_renegotiate_SOURCES = v4l2src-renegotiate.c
+v4l2src_renegotiate_CFLAGS  = $(GST_BASE_CFLAGS) $(GST_CFLAGS)
+v4l2src_renegotiate_LDADD = $(GST_BASE_LIBS) $(GST_LIBS)

tests/examples/v4l2/meson.build

@@ -3,3 +3,9 @@ executable('camctrl', 'camctrl.c',
   c_args : gst_plugins_good_args,
   include_directories : [configinc],
   install: false)
+
+executable('v4l2src-renegotiate', 'v4l2src-renegotiate.c',
+  dependencies: [gst_dep],
+  c_args : gst_plugins_good_args,
+  include_directories : [configinc],
+  install: false)

tests/examples/v4l2/v4l2src-renegotiate.c

@@ -0,0 +1,169 @@
+/* GStreamer
+ *
+ * Copyright (C) 2015 Samsung Electronics. All rights reserved.
+ *   Author: Thiago Santos <thiagoss@osg.samsung.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., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+/* demo for showing v4l2src renegotiating */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+
+/* Options */
+static gchar *device = "/dev/video0";
+static gchar *videosink = "autovideosink";
+static gboolean enable_dmabuf = FALSE;
+static gchar *def_resolutions[] = {
+  "320x240",
+  "1280x720",
+  "640x480",
+  NULL
+};
+
+static gchar **resolutions = def_resolutions;
+
+static GOptionEntry entries[] = {
+  {"device", 'd', 0, G_OPTION_ARG_STRING, &device, "V4L2 Camera Device",
+      NULL},
+  {"videosink", 's', 0, G_OPTION_ARG_STRING, &videosink, "Video Sink to use",
+      NULL},
+  {"enable-dmabuf", 'z', 0, G_OPTION_ARG_NONE, &enable_dmabuf,
+      "Enable DMABuf", NULL},
+  {"resolution", 'r', 0, G_OPTION_ARG_STRING_ARRAY, &resolutions,
+      "Add a resolution to the list", NULL},
+  {NULL}
+};
+
+static GMainLoop *loop;
+static GstElement *pipeline;
+static GstElement *src, *capsfilter;
+static gint index = 0;
+
+static gboolean
+bus_callback (GstBus * bus, GstMessage * message, gpointer data)
+{
+  switch (message->type) {
+    case GST_MESSAGE_EOS:
+      g_main_loop_quit (loop);
+      break;
+    case GST_MESSAGE_ERROR:{
+      GError *gerror;
+      gchar *debug;
+
+      gst_message_parse_error (message, &gerror, &debug);
+      gst_object_default_error (GST_MESSAGE_SRC (message), gerror, debug);
+      g_error_free (gerror);
+      g_free (debug);
+      g_main_loop_quit (loop);
+      break;
+    }
+    default:
+      break;
+  }
+
+  return TRUE;
+}
+
+static gboolean
+change_caps (gpointer data)
+{
+  GstCaps *caps;
+  GStrv res;
+  gchar *caps_str;
+
+  if (!resolutions[index]) {
+    gst_element_send_event (pipeline, gst_event_new_eos ());
+    return FALSE;
+  }
+
+  g_print ("Setting resolution to '%s'\n", resolutions[index]);
+
+  res = g_strsplit (resolutions[index++], "x", 2);
+  if (!res[0] || !res[1]) {
+    g_warning ("Can't parse resolution: %s", resolutions[index - 1]);
+    g_strfreev (res);
+    return TRUE;
+  }
+
+  caps_str = g_strdup_printf ("video/x-raw,width=%s,height=%s", res[0], res[1]);
+  caps = gst_caps_from_string (caps_str);
+  g_object_set (capsfilter, "caps", caps, NULL);
+
+  g_strfreev (res);
+  g_free (caps_str);
+  gst_caps_unref (caps);
+
+  return TRUE;
+}
+
+gint
+main (gint argc, gchar ** argv)
+{
+  GstBus *bus;
+  GError *error = NULL;
+  GOptionContext *context;
+  gchar *desc;
+
+  context = g_option_context_new ("- test v4l2src live renegotition");
+  g_option_context_add_main_entries (context, entries, GETTEXT_PACKAGE);
+  g_option_context_add_group (context, gst_init_get_option_group ());
+  if (!g_option_context_parse (context, &argc, &argv, &error)) {
+    g_print ("option parsing failed: %s\n", error->message);
+    g_error_free (error);
+    return 1;
+  }
+
+  loop = g_main_loop_new (NULL, FALSE);
+
+  desc = g_strdup_printf ("v4l2src name=src device=\"%s\" io-mode=\"%s\" "
+      "! capsfilter name=cf ! %s", device, enable_dmabuf ? "dmabuf" : "mmap",
+      videosink);
+  pipeline = gst_parse_launch (desc, &error);
+  if (!pipeline) {
+    g_print ("failed to create pipeline: %s", error->message);
+    g_error_free (error);
+    return 1;
+  }
+
+  src = gst_bin_get_by_name (GST_BIN (pipeline), "src");
+  capsfilter = gst_bin_get_by_name (GST_BIN (pipeline), "cf");
+
+  bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
+  gst_bus_add_watch (bus, bus_callback, NULL);
+  gst_object_unref (bus);
+
+  change_caps (NULL);
+
+  /* play and wait */
+  gst_element_set_state (pipeline, GST_STATE_PLAYING);
+
+  g_timeout_add_seconds (3, change_caps, NULL);
+
+  /* mainloop and wait for eos */
+  g_main_loop_run (loop);
+
+  /* stop and cleanup */
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  gst_object_unref (src);
+  gst_object_unref (capsfilter);
+  gst_object_unref (GST_OBJECT (pipeline));
+  g_main_loop_unref (loop);
+  return 0;
+}