qtmux: deprecate the streamable property for non-fragmented MP4

The streamable property only makes sense for fragmented MP4.
https://bugzilla.gnome.org/show_bug.cgi?id=707242

gst/isomp4/gstqtmux.c

@@ -278,6 +278,9 @@ gst_qt_mux_class_init (GstQTMuxClass * klass)
 {
   GObjectClass *gobject_class;
   GstElementClass *gstelement_class;
+  const gchar *streamable_desc;
+#define STREAMABLE_DESC "If set to true, the output should be as if it is to "\
+  "be streamed and hence no indexes written or duration written."
 
   gobject_class = (GObjectClass *) klass;
   gstelement_class = (GstElementClass *) klass;
@@ -288,6 +291,13 @@ gst_qt_mux_class_init (GstQTMuxClass * klass)
   gobject_class->get_property = gst_qt_mux_get_property;
   gobject_class->set_property = gst_qt_mux_set_property;
 
+  if (klass->format == GST_QT_MUX_FORMAT_ISML) {
+    streamable_desc = STREAMABLE_DESC;
+  } else {
+    streamable_desc =
+        STREAMABLE_DESC " (DEPRECATED, only valid for fragmented MP4)";
+  }
+
   g_object_class_install_property (gobject_class, PROP_MOVIE_TIMESCALE,
       g_param_spec_uint ("movie-timescale", "Movie timescale",
           "Timescale to use in the movie (units per second)",
@@ -337,9 +347,7 @@ gst_qt_mux_class_init (GstQTMuxClass * klass)
           2000 : DEFAULT_FRAGMENT_DURATION,
           G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
   g_object_class_install_property (gobject_class, PROP_STREAMABLE,
-      g_param_spec_boolean ("streamable", "Streamable",
-          "If set to true, the output should be as if it is to be streamed "
-          "and hence no indexes written or duration written.",
+      g_param_spec_boolean ("streamable", "Streamable", streamable_desc,
           DEFAULT_STREAMABLE,
           G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
 
@@ -3399,9 +3407,14 @@ gst_qt_mux_set_property (GObject * object,
     case PROP_FRAGMENT_DURATION:
       qtmux->fragment_duration = g_value_get_uint (value);
       break;
-    case PROP_STREAMABLE:
-      qtmux->streamable = g_value_get_boolean (value);
+    case PROP_STREAMABLE:{
+      GstQTMuxClass *qtmux_klass =
+          (GstQTMuxClass *) (G_OBJECT_GET_CLASS (qtmux));
+      if (qtmux_klass->format == GST_QT_MUX_FORMAT_ISML) {
+        qtmux->streamable = g_value_get_boolean (value);
+      }
       break;
+    }
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;