diff --git a/lib/polyfill/mediasource.js b/lib/polyfill/mediasource.js
index eab297881..4accb035a 100644
--- a/lib/polyfill/mediasource.js
+++ b/lib/polyfill/mediasource.js
@@ -30,7 +30,7 @@ shaka.polyfill.MediaSource = class {
     // platform detection tricks to decide which patches to install.
     const safariVersion = shaka.util.Platform.safariVersion();
 
-    if (!window.MediaSource) {
+    if (!window.MediaSource && !window.ManagedMediaSource) {
       shaka.log.info('No MSE implementation available.');
     } else if (shaka.util.Platform.isChromecast()) {
       shaka.log.info('Patching Chromecast MSE bugs.');
@@ -158,12 +158,25 @@ shaka.polyfill.MediaSource = class {
    * @private
    */
   static rejectContainer_(container) {
-    const isTypeSupported = MediaSource.isTypeSupported;
+    const isTypeSupported =
+        // eslint-disable-next-line no-restricted-syntax
+        MediaSource.isTypeSupported.bind(MediaSource);
 
     MediaSource.isTypeSupported = (mimeType) => {
       const actualContainer = shaka.util.MimeUtils.getContainerType(mimeType);
       return actualContainer != container && isTypeSupported(mimeType);
     };
+
+    if (window.ManagedMediaSource) {
+      const isTypeSupportedManaged =
+          // eslint-disable-next-line no-restricted-syntax
+          ManagedMediaSource.isTypeSupported.bind(ManagedMediaSource);
+
+      window.ManagedMediaSource.isTypeSupported = (mimeType) => {
+        const actualContainer = shaka.util.MimeUtils.getContainerType(mimeType);
+        return actualContainer != container && isTypeSupportedManaged(mimeType);
+      };
+    }
   }
 
   /**
@@ -175,12 +188,25 @@ shaka.polyfill.MediaSource = class {
    * @private
    */
   static rejectCodec_(codec) {
-    const isTypeSupported = MediaSource.isTypeSupported;
+    const isTypeSupported =
+        // eslint-disable-next-line no-restricted-syntax
+        MediaSource.isTypeSupported.bind(MediaSource);
 
     MediaSource.isTypeSupported = (mimeType) => {
       const actualCodec = shaka.util.MimeUtils.getCodecBase(mimeType);
       return actualCodec != codec && isTypeSupported(mimeType);
     };
+
+    if (window.ManagedMediaSource) {
+      const isTypeSupportedManaged =
+          // eslint-disable-next-line no-restricted-syntax
+          ManagedMediaSource.isTypeSupported.bind(ManagedMediaSource);
+
+      window.ManagedMediaSource.isTypeSupported = (mimeType) => {
+        const actualCodec = shaka.util.MimeUtils.getCodecBase(mimeType);
+        return actualCodec != codec && isTypeSupportedManaged(mimeType);
+      };
+    }
   }
 
   /**