Issue when changing sources in an ended event

[fxthomas]

Hello all,

We've been hitting a strange issue with the latest MediaElement.js (4.2.10) at airsonic/airsonic#1080 that we can't seem to resolve, and we'd appreciate some help.

The following sequence of events seems to work for HTML5 MediaElement, but not with MediaElement.js. For me, this fails in Firefox (67/68) only, not on Chromium (75).

1. Set src, then call load() and play() for a first MP3 stream.
2. In the ended event handler, do the same for a second MP3 stream.

Step 2 appears to buffer the second stream correctly, but playback never starts, and the console shows AbortError: The fetching process for the media resource was aborted by the user agent at the user's request.:

I've managed to put together a short reproduction case at https://github.com/fxthomas/mediaelement-test-aborterror.

[fxthomas]

I think I've managed to track down the root cause of this issue. I updated the test repo with some more info about it!

The root cause appears to be a call to player.pause() in one of the handlers for the ended event.

[fxthomas]

I've dug a bit into it, and managed to track the introduction of that particular pause call back to 33080d6 (yup, that's old). That does not tell me a lot, unfortunately...

It seems that calling pause() should be unnecessary when we're in the ended event (the stream should have already finished playing), but maybe I'm missing something.

Is it possibly needed by a renderer (in which case, which one?) or does it trigger UI updates (in which case, can we decouple them from calls to pause())?

I'll continue to dig, maybe I'll find something.

[karawitan]

Any success with this one ?

[fxthomas]

Well, holidays prevented me from working on this, but I'm back 😉

After doing some more investigation in the internals of the MEJS player, I found out that our (in Airsonic) initialization order was a bit unusual. In particular, we were adding events to the MEJS player before it was fully initialized, and our event handlers were carried over once MEJS had finished its full initialization.

I believe that airsonic/airsonic#1254 fixes the issue completely on our side, and I'm not certain it should even be considered a bug on MEJS's part (since technically we were using it somewhat wrong).

[jvoisin]

It might be detecting added event handling during initialization to warn that something is wrong, or at least document it somewhere :)

[karawitan]

Ok IIUC, there is no issue in MediaElement ... closing ..