diff --git a/data/boxes-udta.csv b/data/boxes-udta.csv
index b41764f..ebdd1bb 100644
--- a/data/boxes-udta.csv
+++ b/data/boxes-udta.csv
@@ -40,4 +40,4 @@ urat,User 'star' rating of the media,3GPP
 yrrc,Year when media was recorded,3GPP
 swre,Name and version number of the software that generated this movie,Apple
 diap,Dialogue processing (DialogueProcessingBox),ETSI AC-4
-ctlc,Content type for loudness control,Apple
+ctlc,Content type for loudness control,AppleCTLC
diff --git a/data/specifications.json b/data/specifications.json
index 8fbf03c..58fbad6 100644
--- a/data/specifications.json
+++ b/data/specifications.json
@@ -71,6 +71,12 @@
     "description": "HEVC Video with Alpha, Interoperability Profile. Apple Inc.",
     "MPEG": false
   },
+  {
+    "specification": "AppleCTLC",
+    "url": "https://developer.apple.com/download/files/Content-Type-Loudness-Specification.pdf",
+    "description": "Content Type for Loudness Control. Apple Inc.",
+    "MPEG": false
+  },
   {
     "specification": "ATSC 3.0 A337",
     "url": "https://www.atsc.org/atsc-documents/type/3-0-standards/",