From e0d103757a4b282dd3a91782ad1497676965b99a Mon Sep 17 00:00:00 2001
From: Rob Walch <rob@jwplayer.com>
Date: Thu, 15 Apr 2021 13:44:44 -0400
Subject: [PATCH] Fix AES-128 in streams with alt-audio tracks Fixes #3772
 (v1.0 regression)

---
 src/controller/audio-stream-controller.ts |  6 +----
 src/controller/base-stream-controller.ts  | 28 ++++++++++++++++++-----
 src/controller/stream-controller.ts       | 13 ++++-------
 3 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/src/controller/audio-stream-controller.ts b/src/controller/audio-stream-controller.ts
index 56e7e74c99b..936caf010d5 100644
--- a/src/controller/audio-stream-controller.ts
+++ b/src/controller/audio-stream-controller.ts
@@ -344,11 +344,7 @@ class AudioStreamController
     }
 
     if (frag.decryptdata?.keyFormat === 'identity' && !frag.decryptdata?.key) {
-      this.log(
-        `Loading key for ${frag.sn} of [${trackDetails.startSN} ,${trackDetails.endSN}],track ${trackId}`
-      );
-      this.state = State.KEY_LOADING;
-      hls.trigger(Events.KEY_LOADING, { frag });
+      this.loadKey(frag, trackDetails);
     } else {
       this.loadFragment(frag, trackDetails, targetBufferTime);
     }
diff --git a/src/controller/base-stream-controller.ts b/src/controller/base-stream-controller.ts
index 647d9c6a1b3..b2a7dce316a 100644
--- a/src/controller/base-stream-controller.ts
+++ b/src/controller/base-stream-controller.ts
@@ -236,12 +236,17 @@ export default class BaseStreamController
   }
 
   onKeyLoaded(event: Events.KEY_LOADED, data: KeyLoadedData) {
-    if (this.state === State.KEY_LOADING && this.levels) {
-      this.state = State.IDLE;
-      const levelDetails = this.levels[data.frag.level].details;
-      if (levelDetails) {
-        this.loadFragment(data.frag, levelDetails, data.frag.start);
-      }
+    if (
+      this.state !== State.KEY_LOADING ||
+      data.frag !== this.fragCurrent ||
+      !this.levels
+    ) {
+      return;
+    }
+    this.state = State.IDLE;
+    const levelDetails = this.levels[data.frag.level].details;
+    if (levelDetails) {
+      this.loadFragment(data.frag, levelDetails, data.frag.start);
     }
   }
 
@@ -264,6 +269,17 @@ export default class BaseStreamController
     super.onHandlerDestroyed();
   }
 
+  protected loadKey(frag: Fragment, details: LevelDetails) {
+    this.log(
+      `Loading key for ${frag.sn} of [${details.startSN}-${details.endSN}], ${
+        this.logPrefix === '[stream-controller]' ? 'level' : 'track'
+      } ${frag.level}`
+    );
+    this.state = State.KEY_LOADING;
+    this.fragCurrent = frag;
+    this.hls.trigger(Events.KEY_LOADING, { frag });
+  }
+
   protected loadFragment(
     frag: Fragment,
     levelDetails: LevelDetails,
diff --git a/src/controller/stream-controller.ts b/src/controller/stream-controller.ts
index 9cc7f920aa8..b0543fa4262 100644
--- a/src/controller/stream-controller.ts
+++ b/src/controller/stream-controller.ts
@@ -306,20 +306,12 @@ export default class StreamController
     // We want to load the key if we're dealing with an identity key, because we will decrypt
     // this content using the key we fetch. Other keys will be handled by the DRM CDM via EME.
     if (frag.decryptdata?.keyFormat === 'identity' && !frag.decryptdata?.key) {
-      this.log(
-        `Loading key for ${frag.sn} of [${levelDetails.startSN}-${levelDetails.endSN}], level ${level}`
-      );
-      this.loadKey(frag);
+      this.loadKey(frag, levelDetails);
     } else {
       this.loadFragment(frag, levelDetails, targetBufferTime);
     }
   }
 
-  private loadKey(frag: Fragment) {
-    this.state = State.KEY_LOADING;
-    this.hls.trigger(Events.KEY_LOADING, { frag });
-  }
-
   protected loadFragment(
     frag: Fragment,
     levelDetails: LevelDetails,
@@ -473,6 +465,9 @@ export default class StreamController
     if (fragCurrent?.loader) {
       fragCurrent.loader.abort();
     }
+    if (this.state === State.KEY_LOADING) {
+      this.state = State.IDLE;
+    }
     this.nextLoadPosition = this.getLoadPosition();
   }