Get KEYID from init segment 'tenc' when not found elsewhere

Fixes #7541

Author: robwalch

src/controller/eme-controller.ts

@@ -803,10 +803,9 @@ class EMEController extends Logger implements ComponentAPI {
     const generateRequestFilter =
       this.config.drmSystems?.[context.keySystem]?.generateRequest;
     if (generateRequestFilter) {
-      const contextWithLevelKey: MediaKeySessionContextAndLevelKey = {
+      const contextWithLevelKey = Object.assign({}, context, {
         decryptdata: levelKey,
-        ...context,
-      };
+      });
       try {
         const mappedInitData: ReturnType<typeof generateRequestFilter> =
           generateRequestFilter.call(
@@ -1173,10 +1172,9 @@ class EMEController extends Logger implements ComponentAPI {
     levelKey: LevelKey,
     keyMessage: ArrayBuffer,
   ): Promise<void> {
-    const contextWithLevelKey: MediaKeySessionContextAndLevelKey = {
+    const contextWithLevelKey = Object.assign({}, context, {
       decryptdata: levelKey,
-      ...context,
-    };
+    });
     return this.requestLicense(
       contextWithLevelKey,
       new Uint8Array(keyMessage),

src/loader/level-key.ts

@@ -178,10 +178,6 @@ export class LevelKey implements DecryptData {
           }
           if (!this.keyId) {
             this.keyId = getKeyIdFromPlayReadyKey(levelKeys);
-            if (!this.keyId) {
-              const offset = keyBytes.length - 22;
-              this.keyId = keyBytes.subarray(offset, offset + 16);
-            }
           }
           break;
         case KeySystemFormats.PLAYREADY: {
@@ -211,22 +207,18 @@ export class LevelKey implements DecryptData {
       }
     }
 
-    // Default behavior: assign a new keyId for each uri
+    // Default behavior: get keyId from other KEY tag or URI lookup
     if (!this.keyId || this.keyId.byteLength !== 16) {
-      let keyId: Uint8Array<ArrayBuffer> | null | undefined =
-        keyUriToKeyIdMap[this.uri];
+      let keyId: Uint8Array<ArrayBuffer> | null | undefined;
+      keyId = getKeyIdFromWidevineKey(levelKeys);
       if (!keyId) {
-        keyId = getKeyIdFromWidevineKey(levelKeys);
+        keyId = getKeyIdFromPlayReadyKey(levelKeys);
         if (!keyId) {
-          keyId = getKeyIdFromPlayReadyKey(levelKeys);
-          if (!keyId) {
-            const val =
-              Object.keys(keyUriToKeyIdMap).length % Number.MAX_SAFE_INTEGER;
-            keyId = new Uint8Array(16);
-            const dv = new DataView(keyId.buffer, 12, 4); // Just set the last 4 bytes
-            dv.setUint32(0, val);
-          }
+          keyId = keyUriToKeyIdMap[this.uri];
         }
+      }
+      if (keyId) {
+        this.keyId = keyId;
         LevelKey.setKeyIdForUri(this.uri, keyId);
       }
     }