Disable the local video button if no camera is available.

resources/languages/resources.properties

@@ -287,6 +287,7 @@ service.gui.NEW_MESSAGE=New message
 service.gui.NEW_NAME=New name
 service.gui.NEW_STATUS_MESSAGE=New status message
 service.gui.NO=No
+service.gui.NO_CAMERA_AVAILABLE=No camera available
 service.gui.NO_AVAILABLE_ROOMS=The list of rooms for this server is currently not available.
 service.gui.NO_CONTACTS_FOUND=No matching contacts found. Press Ctrl+Enter to call {0} or use the buttons below.
 service.gui.NO_MESSAGE=No message

src/net/java/sip/communicator/impl/gui/main/call/CallDialog.java

@@ -22,6 +22,8 @@
 import net.java.sip.communicator.impl.gui.main.call.conference.*;
 import net.java.sip.communicator.impl.gui.utils.*;
 import net.java.sip.communicator.service.gui.*;
+import net.java.sip.communicator.service.neomedia.*;
+import net.java.sip.communicator.service.neomedia.device.*;
 import net.java.sip.communicator.service.protocol.*;
 import net.java.sip.communicator.service.protocol.event.*;
 import net.java.sip.communicator.util.*;
@@ -527,7 +529,14 @@ public void enableButtons()
                 = protocolProvider.getOperationSet(
                     OperationSetVideoTelephony.class);
 
-            if (videoTelephony != null)
+            MediaDevice videoDevice = GuiActivator.getMediaService()
+                .getDefaultDevice(  MediaType.VIDEO,
+                                    MediaUseCase.CALL);
+
+            // If the video telephony is supported and the default video device
+            // isn't null, i.e. there's an available camera to the video we
+            // enable the video button.
+            if (videoTelephony != null && videoDevice != null)
             {
                 videoButton.setEnabled(true);
 
@@ -537,6 +546,9 @@ public void enableButtons()
                     && !videoButton.isSelected())
                     setVideoButtonSelected(true);
             }
+            else if (videoDevice == null)
+                videoButton.setToolTipText(GuiActivator.getResources()
+                    .getI18NString("service.gui.NO_CAMERA_AVAILABLE"));
 
             OperationSetDesktopSharingServer desktopSharing
                 = protocolProvider.getOperationSet(