diff --git a/README.md b/README.md
index d0930ca..6f567c3 100644
--- a/README.md
+++ b/README.md
@@ -137,7 +137,7 @@ or
 You can control the license and certificate request processes by providing the following methods instead of the properties discussed above:
 
 * `getCertificate()` - Allows asynchronous retrieval of a certificate.
-* `getContentId()` - Allows synchronous retrieval of a content ID.
+* `getContentId()` - Allows synchronous retrieval of a content ID. It takes `emeOptions`, as well as the `initData` converted into a String.
 * `getLicense()` - Allows asynchronous retrieval of a license.
 
 ```js
@@ -149,7 +149,7 @@ You can control the license and certificate request processes by providing the f
         // if err, callback(err)
         // if success, callback(null, certificate)
       },
-      getContentId: function(emeOptions, initData) {
+      getContentId: function(emeOptions, contentId) {
         // return content ID
       },
       getLicense: function(emeOptions, contentId, keyMessage, callback) {
diff --git a/src/eme.js b/src/eme.js
index 97781c2..8c70c7a 100644
--- a/src/eme.js
+++ b/src/eme.js
@@ -1,7 +1,7 @@
 import videojs from 'video.js';
 import { requestPlayreadyLicense } from './playready';
 import window from 'global/window';
-import {mergeAndRemoveNull} from './utils';
+import {uint8ArrayToString, mergeAndRemoveNull} from './utils';
 import {httpResponseHandler} from './http-handler.js';
 import {
   defaultGetCertificate as defaultFairplayGetCertificate,
@@ -398,7 +398,7 @@ export const standard5July2016 = ({
   }
 
   const contentId = keySystemOptions.getContentId ?
-    keySystemOptions.getContentId(options, initData) : null;
+    keySystemOptions.getContentId(options, uint8ArrayToString(initData)) : null;
 
   if (typeof video.mediaKeysObject === 'undefined') {
     // Prevent entering this path again.
diff --git a/src/fairplay.js b/src/fairplay.js
index c5ec89c..591b902 100644
--- a/src/fairplay.js
+++ b/src/fairplay.js
@@ -7,7 +7,7 @@
  */
 import videojs from 'video.js';
 import window from 'global/window';
-import {stringToUint16Array, uint8ArrayToString, getHostnameFromUri, mergeAndRemoveNull} from './utils';
+import {stringToUint16Array, uint16ArrayToString, getHostnameFromUri, mergeAndRemoveNull} from './utils';
 import {httpResponseHandler} from './http-handler.js';
 
 export const FAIRPLAY_KEY_SYSTEM = 'com.apple.fps.1_0';
@@ -128,8 +128,8 @@ export const defaultGetCertificate = (fairplayOptions) => {
   };
 };
 
-export const defaultGetContentId = (emeOptions, initData) => {
-  return getHostnameFromUri(uint8ArrayToString(initData));
+export const defaultGetContentId = (emeOptions, initDataString) => {
+  return getHostnameFromUri(initDataString);
 };
 
 export const defaultGetLicense = (fairplayOptions) => {
@@ -174,7 +174,7 @@ const fairplay = ({video, initData, options, eventBus}) => {
       initData,
       getLicense,
       options,
-      contentId: getContentId(options, initData),
+      contentId: getContentId(options, uint16ArrayToString(initData)),
       eventBus
     });
   });
diff --git a/src/utils.js b/src/utils.js
index c5f990e..b44394a 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -17,6 +17,10 @@ export const uint8ArrayToString = (array) => {
   return String.fromCharCode.apply(null, new Uint8Array(array.buffer || array));
 };
 
+export const uint16ArrayToString = (array) => {
+  return String.fromCharCode.apply(null, new Uint16Array(array.buffer || array));
+};
+
 export const getHostnameFromUri = (uri) => {
   const link = document.createElement('a');