From a9468138aff112a6d5bfa4b1b17c9454c0d706cc Mon Sep 17 00:00:00 2001
From: Rob Walch <rwalch@apple.com>
Date: Thu, 2 Feb 2023 19:10:23 -0800
Subject: [PATCH 1/2] Log error and detach if MediaSource 'sourceopen' is
 interrupted Resolves #4952

---
 src/controller/buffer-controller.ts             | 17 +++++++++++++++--
 .../controller/buffer-controller-operations.ts  |  2 ++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/controller/buffer-controller.ts b/src/controller/buffer-controller.ts
index 8223f351504..d317533bd5a 100644
--- a/src/controller/buffer-controller.ts
+++ b/src/controller/buffer-controller.ts
@@ -159,6 +159,7 @@ export default class BufferController implements ComponentAPI {
       media.src = self.URL.createObjectURL(ms);
       // cache the locally generated object url
       this._objectUrl = media.src;
+      media.addEventListener('emptied', this._onMediaEmptied);
     }
   }
 
@@ -188,6 +189,7 @@ export default class BufferController implements ComponentAPI {
       // Detach properly the MediaSource from the HTMLMediaElement as
       // suggested in https://github.com/w3c/media-source/issues/53.
       if (media) {
+        media.removeEventListener('emptied', this._onMediaEmptied);
         if (_objectUrl) {
           self.URL.revokeObjectURL(_objectUrl);
         }
@@ -785,11 +787,12 @@ export default class BufferController implements ComponentAPI {
 
   // Keep as arrow functions so that we can directly reference these functions directly as event listeners
   private _onMediaSourceOpen = () => {
-    const { hls, media, mediaSource } = this;
+    const { media, mediaSource } = this;
     logger.log('[buffer-controller]: Media source opened');
     if (media) {
+      media.removeEventListener('emptied', this._onMediaEmptied);
       this.updateMediaElementDuration();
-      hls.trigger(Events.MEDIA_ATTACHED, { media });
+      this.hls.trigger(Events.MEDIA_ATTACHED, { media });
     }
 
     if (mediaSource) {
@@ -807,6 +810,16 @@ export default class BufferController implements ComponentAPI {
     logger.log('[buffer-controller]: Media source ended');
   };
 
+  private _onMediaEmptied = () => {
+    const { media, _objectUrl } = this;
+    if (media && media.src !== _objectUrl) {
+      logger.error(
+        `Media reset while attaching MediaSource, detaching media (${_objectUrl} > ${media.src})`
+      );
+      this.hls.detachMedia();
+    }
+  };
+
   private _onSBUpdateStart(type: SourceBufferName) {
     const { operationQueue } = this;
     const operation = operationQueue.current(type);
diff --git a/tests/unit/controller/buffer-controller-operations.ts b/tests/unit/controller/buffer-controller-operations.ts
index 31631b2773c..66b99dc6aac 100644
--- a/tests/unit/controller/buffer-controller-operations.ts
+++ b/tests/unit/controller/buffer-controller-operations.ts
@@ -61,6 +61,8 @@ class MockMediaElement {
   public currentTime: number = 0;
   public duration: number = Infinity;
   public textTracks: any[] = [];
+  addEventListener() {}
+  removeEventListener() {}
 }
 
 const queueNames: Array<SourceBufferName> = ['audio', 'video'];

From 4fdda6cf1d3a586e0dd8b60707dfa276555f28fb Mon Sep 17 00:00:00 2001
From: Rob Walch <robwalch@users.noreply.github.com>
Date: Tue, 7 Feb 2023 13:18:23 -0800
Subject: [PATCH 2/2] Update src/controller/buffer-controller.ts

---
 src/controller/buffer-controller.ts | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/controller/buffer-controller.ts b/src/controller/buffer-controller.ts
index d317533bd5a..7e42aa8a5b0 100644
--- a/src/controller/buffer-controller.ts
+++ b/src/controller/buffer-controller.ts
@@ -814,9 +814,8 @@ export default class BufferController implements ComponentAPI {
     const { media, _objectUrl } = this;
     if (media && media.src !== _objectUrl) {
       logger.error(
-        `Media reset while attaching MediaSource, detaching media (${_objectUrl} > ${media.src})`
+        `Media element src was set while attaching MediaSource (${_objectUrl} > ${media.src})`
       );
-      this.hls.detachMedia();
     }
   };