Minor change

media_cas_packager_sdk/public/wv_cas_ecm.h

@@ -22,11 +22,12 @@ namespace cas {
 // Information needed to generate content key portion of ECM.
 // Fields:
 //   |key_id| key ID for the content key, must be 16 bytes.
-//   |key| content key value (aka control word), must be 16 bytes. It will be
-//      wrapped (encrypted) by corresponding entitlement key (decided by track
-//      type), together with |wrapped_key_iv| as the initial vector.
-//   |content_iv| content initial vector, must be 8 or 16 bytes. It is used for
-//      decrypting the content stream.
+//   |key| content key value (aka control word), must be 8 (DvbCsa2) or 16 bytes
+//      (all other crypto modes). It will be wrapped (encrypted) by
+//      corresponding entitlement key (decided by track type), together with
+//      |wrapped_key_iv| as the initial vector.
+//   |content_iv| content initial vector, must be 8 (DvbCsa2) or 16 bytes (all
+//      other crypto modes). It is used for decrypting the content stream.
 //   |wrapped_key_iv| must be 16 bytes. It is used to encrypt |key|.
 struct WvCasContentKeyInfo {
   std::string key_id;