tag: Adds GST_TAG_APPLICATION_DATA

Adds GST_TAG_APPLICATION_DATA for representing arbitrary private
data that applications might want to store into tags. Exif/id3,
for example, have tags for this.

API: GST_TAG_APPLICATION_DATA

Fixes #626651

docs/gst/gstreamer-sections.txt

@@ -2214,6 +2214,7 @@ GST_TAG_USER_RATING
 GST_TAG_DEVICE_MANUFACTURER
 GST_TAG_DEVICE_MODEL
 GST_TAG_APPLICATION_NAME
+GST_TAG_APPLICATION_DATA
 GST_TAG_IMAGE_ORIENTATION
 
 gst_tag_register

gst/gsttaglist.c

@@ -355,6 +355,9 @@ _gst_tag_initialize (void)
       _("Model of the device used to create this media"), NULL);
   gst_tag_register (GST_TAG_APPLICATION_NAME, GST_TAG_FLAG_META, G_TYPE_STRING,
       _("application name"), _("Application used to create the media"), NULL);
+  gst_tag_register (GST_TAG_APPLICATION_DATA, GST_TAG_FLAG_META,
+      GST_TYPE_BUFFER, _("application data"),
+      _("Arbitrary application data to be serialized into the media"), NULL);
   gst_tag_register (GST_TAG_IMAGE_ORIENTATION, GST_TAG_FLAG_META, G_TYPE_STRING,
       _("image orientation"),
       _("How the image should be rotated or flipped before display"), NULL);

gst/gsttaglist.h

@@ -967,6 +967,17 @@ gboolean     gst_tag_list_get_buffer_index  (const GstTagList * list,
  * Since: 0.10.31
  */
 #define GST_TAG_APPLICATION_NAME                  "application-name"
+/**
+ * GST_TAG_APPLICATION_DATA:
+ *
+ * Arbitrary application data (buffer)
+ *
+ * Some formats allow application's to add their own arbitrary data
+ * into files. This data is application's dependent.
+ *
+ * Since: 0.10.31
+ */
+#define GST_TAG_APPLICATION_DATA          "application-data"
 /**
  * GST_TAG_IMAGE_ORIENTATION:
  *