Prevent same MediaKeys from being set on media element by eme-controller

robwalch · robwalch · commit 4cc80bf1d793 · 2025-05-29T09:04:41.000-07:00
Follow up to #7216
diff --git a/src/controller/base-stream-controller.ts b/src/controller/base-stream-controller.ts
@@ -31,7 +31,6 @@ import {
   getPartWith,
   updateFragPTSDTS,
 } from '../utils/level-helper';
-import { getKeySystemsForConfig } from '../utils/mediakeys-helper';
 import { appendUint8Array } from '../utils/mp4-tools';
 import TimeRanges from '../utils/time-ranges';
 import type { FragmentTracker } from './fragment-tracker';
diff --git a/src/controller/eme-controller.ts b/src/controller/eme-controller.ts
@@ -92,6 +92,7 @@ class EMEController extends Logger implements ComponentAPI {
   private keyIdToKeySessionPromise: {
     [keyId: string]: Promise<MediaKeySessionContext>;
   } = {};
+  private mediaKeys: MediaKeys | null = null;
   private setMediaKeysQueue: Promise<void>[] = EMEController.CDMCleanupPromise
     ? [EMEController.CDMCleanupPromise]
     : [];
@@ -756,19 +757,24 @@ class EMEController extends Logger implements ComponentAPI {
     keySystem: KeySystems,
     mediaKeys: MediaKeys,
   ): Promise<void> {
+    if (this.mediaKeys === mediaKeys) {
+      return Promise.resolve();
+    }
     const queue = this.setMediaKeysQueue.slice();
 
     this.log(`Setting media-keys for "${keySystem}"`);
     // Only one setMediaKeys() can run at one time, and multiple setMediaKeys() operations
     // can be queued for execution for multiple key sessions.
     const setMediaKeysPromise = Promise.all(queue).then(() => {
       if (!this.media) {
+        this.mediaKeys = null;
         throw new Error(
           'Attempted to set mediaKeys without media element attached',
         );
       }
       return this.media.setMediaKeys(mediaKeys);
     });
+    this.mediaKeys = mediaKeys;
     this.setMediaKeysQueue.push(setMediaKeysPromise);
     return setMediaKeysPromise.then(() => {
       this.log(`Media-keys set for "${keySystem}"`);
@@ -1325,12 +1331,14 @@ class EMEController extends Logger implements ComponentAPI {
       media.removeEventListener('encrypted', this.onMediaEncrypted);
       media.removeEventListener('waitingforkey', this.onWaitingForKey);
       this.media = null;
+      this.mediaKeys = null;
     }
   }
 
   private _clear(media) {
     const mediaKeysList = this.mediaKeySessions;
     this._requestLicenseFailureCount = 0;
+    this.mediaKeys = null;
     this.setMediaKeysQueue = [];
     this.mediaKeySessions = [];
     this.keyIdToKeySessionPromise = {};
