taglist: add a new "encoded-by" tag

Usecase: ID3v2 TENC ("Encoded by") frame.

API: GST_TAG_ENCODED_BY

https://bugzilla.gnome.org/show_bug.cgi?id=627268

docs/gst/gstreamer-sections.txt

@@ -2222,6 +2222,7 @@ GST_TAG_ISRC
 GST_TAG_ORGANIZATION
 GST_TAG_COPYRIGHT
 GST_TAG_COPYRIGHT_URI
+GST_TAG_ENCODED_BY
 GST_TAG_COMPOSER
 GST_TAG_CONTACT
 GST_TAG_LICENSE

gst/gsttaglist.c

@@ -189,6 +189,9 @@ _gst_tag_initialize (void)
   gst_tag_register (GST_TAG_COPYRIGHT_URI, GST_TAG_FLAG_META,
       G_TYPE_STRING, _("copyright uri"),
       _("URI to the copyright notice of the data"), NULL);
+  gst_tag_register (GST_TAG_ENCODED_BY, GST_TAG_FLAG_META, G_TYPE_STRING,
+      _("encoded by"), _("name of the encoding person or organization"),
+      gst_tag_merge_strings_with_comma);
   gst_tag_register (GST_TAG_CONTACT, GST_TAG_FLAG_META,
       G_TYPE_STRING,
       _("contact"), _("contact information"), gst_tag_merge_strings_with_comma);

gst/gsttaglist.h

@@ -579,6 +579,19 @@ gboolean     gst_tag_list_get_buffer_index  (const GstTagList * list,
  * Since: 0.10.14
  */
 #define GST_TAG_COPYRIGHT_URI          "copyright-uri"
+/**
+ * GST_TAG_ENCODED_BY:
+ *
+ * name of the person or organisation that encoded the file. May contain a
+ * copyright message if the person or organisation also holds the copyright
+ * (string)
+ *
+ * Note: do not use this field to describe the encoding application. Use
+ * #GST_TAG_APPLICATION_NAME or #GST_TAG_COMMENT for that.
+ *
+ * Since: 0.10.33
+ */
+#define GST_TAG_ENCODED_BY             "encoded-by"
 /**
  * GST_TAG_CONTACT:
  *