Exif / XMP support
* avifImage can now hold Exif and XMP metadata (`avifImageSetMetadataExif`, `avifImageSetMetadataXMP`)
* Support for reading/writing Exif and XMP items
* Now tracking idat boxes across meta boxes
* Support for iloc construction_method 1 (idat)
* Proper handling of the primary item box (pitm) on read
diff --git a/include/avif/internal.h b/include/avif/internal.h
index c0bee2d..f4d39ed 100644
--- a/include/avif/internal.h
+++ b/include/avif/internal.h
@@ -21,11 +21,13 @@
} while (0)
// ---------------------------------------------------------------------------
-// URNs
+// URNs and Content-Types
#define URN_ALPHA0 "urn:mpeg:mpegB:cicp:systems:auxiliary:alpha"
#define URN_ALPHA1 "urn:mpeg:hevc:2015:auxid:1"
+#define CONTENT_TYPE_XMP "application/rdf+xml"
+
// ---------------------------------------------------------------------------
// Utils
