diff --git a/data/standard_features/14496-15/boxes.json b/data/standard_features/14496-15/boxes.json
index dd6d8158..d3db7460 100644
--- a/data/standard_features/14496-15/boxes.json
+++ b/data/standard_features/14496-15/boxes.json
@@ -551,7 +551,13 @@
       "fourcc": "vvnC",
       "description": "VVC Network Abstraction Layer unit configuration",
       "versions": [0],
-      "flags": [],
+      "flags": [
+        {
+          "name": "",
+          "value": "0x000001",
+          "description": "The samples referencing the sample entry do not contain content intended for displaying."
+        }
+      ],
       "containers": [
         {
           "VvcSubpicSampleEntry": ["vvs1"]
diff --git a/data/standard_features/14496-15/track_groups.json b/data/standard_features/14496-15/track_groups.json
index 25f59dbb..b1589b3e 100644
--- a/data/standard_features/14496-15/track_groups.json
+++ b/data/standard_features/14496-15/track_groups.json
@@ -7,6 +7,14 @@
       "description": "alternative extraction source track grouping",
       "containers": ["trgr"],
       "type": "TrackGroupTypeBox",
+      "versions": [0],
+      "flags": [
+        {
+          "name": "",
+          "value": "0x000001",
+          "description": "Indicates the uniqueness of track_group_id"
+        }
+      ],
       "syntax": "aligned(8) class TrackGroupTypeBox('alte') extends FullBox('alte', version = 0, flags = 0)\n{\n\tunsigned int(32) track_group_id;\n\t// the remaining data may be specified \n\t//  for a particular track_group_type\n}"
     },
     {
@@ -14,6 +22,14 @@
       "description": "complete subset track grouping",
       "containers": ["trgr"],
       "type": "TrackGroupTypeBox",
+      "versions": [0],
+      "flags": [
+        {
+          "name": "",
+          "value": "0x000001",
+          "description": "Indicates the uniqueness of track_group_id"
+        }
+      ],
       "syntax": "aligned(8) class TrackGroupTypeBox('cstg') extends FullBox('cstg', version = 0, flags = 0)\n{\n\tunsigned int(32) track_group_id;\n\t// the remaining data may be specified \n\t//  for a particular track_group_type\n}"
     },
     {
@@ -21,6 +37,14 @@
       "description": "a group of VVC subpicture tracks where the VCL NAL units of the time-aligned samples have the same NAL unit type",
       "containers": ["trgr"],
       "type": "TrackGroupTypeBox",
+      "versions": [0],
+      "flags": [
+        {
+          "name": "",
+          "value": "0x000001",
+          "description": "Indicates the uniqueness of track_group_id"
+        }
+      ],
       "syntax": "aligned(8) class TrackGroupTypeBox('snut') extends FullBox('snut', version = 0, flags = 0)\n{\n\tunsigned int(32) track_group_id;\n\t// the remaining data may be specified \n\t//  for a particular track_group_type\n}"
     }
   ]