bufferAppendError on iOS 26.2 when autoStartLoad=false

[gjanblaszczyk]

What version of Hls.js are you using?

1.6.15

What browser (including version) are you using?

Safari

What OS (including version) are you using?

iOS 26.2 (iPhone)

Test stream

Demo test stream for example: Big Buck Bunny - adaptive qualities

Configuration

{
autoStartLoad: false
}

Additional player setup steps

No response

Checklist

• The issue observed is not already reported by searching on Github under https://github.com/video-dev/hls.js/issues
• The issue occurs in the stable client (latest release) on https://hlsjs.video-dev.org/demo and not just on my page
• The issue occurs in the latest client (main branch) on https://hlsjs-dev.video-dev.org/demo and not just on my page
• The stream has correct Access-Control-Allow-Origin headers (CORS)
• There are no network errors such as 404s in the browser console when trying to play the stream

Steps to reproduce

1. Open the latest official hls.js demo page.

In the hls.js configuration, set:

autoStartLoad: false

2. Scroll to the Playback section and click/touch the “Start Loading” button.

3. The video should play without any problems.

4. Now, let's close the Safari app and remove it from the background. I want Safari to be launched with no previous state in memory.

5. Relaunched Safari should open the latest official hls.js demo page.

6. Scroll to the Playback section and click/touch the “Start Loading” button.

7. Instead of loading media segments, playback fails with a fatal:

bufferAppendError

Additional observations

After the error occurs, reloading the page once makes playback work correctly.

However, if Safari is fully terminated (removed from app switcher / memory) and the demo page is opened again:

the issue reproduces consistently.

The problem appears only after a cold Safari start.

Expected behaviour

The video player should play the example video without any problems.

What actually happened?

The video player is frozen, and I see two errors in console output:
Buffer appending error
Buffer append error

Console output

I don't have any

Chrome media internals output

[robwalch]

Does #7683 fix this issue?

[gjanblaszczyk]

Hi Rob,
No, I think it is different problem.
Btw I can't reproduce #7683 on iOS 26.2 and Safari (but maybe #7683 problem is related to desktop Safari only).

[robwalch]

@gjanblaszczyk,

While each issue manifests on a different platform, they both suffer from a common root cause. From what I can tell, in both cases, the MediaSource is closed while media is still attached. The change in #7683 resets the MediaSource when this state is detected, so I suspect that it will address both issues. In fact, I'd like to make sure it does before merging. I had hoped you might be able to verify this.

[gjanblaszczyk]

@robwalch Hmm, maybe it’s better not to close my issue yet, as it looks like the fix #7683 does not actually resolve the problem.
After additional testing, I can see that the failure sequence is different, and simply calling recoverMediaError() does not help in this case.

That said, it appears that the fix #7683 does resolve a different issue that was also reported, so I’ll include it in our test runs.
For now, I’ll pass the fix together with my additional changes to our testers to verify whether the playback is now stable on iPhone.
I’ll follow up later with the test results.

[robwalch]

#7683 (comment)

It sounds like you need to also check hls.loadingEnabled and hls.bufferingEnabled.

After a fatal error, hls.stopLoad() is called and hls.loadingEnabled will be false. Call hls.startLoad() to resume loading.

If loading is still enabled, but buffering of segments has been paused by ManagedMediaSource, hls.bufferingEnabled will be false. Call hls.resumeBuffering() in this case.

[zalishchuk]

@robwalch Default configuration (no autoStartLoad set) from the demo page, buffer errors on first enter after cache reset due to Error: video SourceBuffer error. MediaSource readyState: ended, after page reloads, it works just as expected with no errors. While HLS.js is recovering, it still has a significant impact on event listeners, the order in which they execute, and functionality such as autoplay.

hls-demo.mp4