MP3 HLS in Firefox "No decoders for requested formats" MP3 to MP4 remux required

[jmooradi]

Using information from #1210

Have you read the FAQ and checked for duplicate open issues?:

What version of Shaka Player are you using?:
2.3.2

Can you reproduce the issue with our latest release version?:
yes

Can you reproduce the issue with the latest code from master?:
yes

Are you using the demo app or your own custom app?:
Demo app

If custom app, can you reproduce the issue using our demo app?:

What browser and OS are you using?:
Firefox 59.0 & Mac High Sierra

What are the manifest and license server URIs?:
http://wilma.betalounge.com/mod/_definst_/mp3:lounge/2005/050910_dsl_de.mp3/playlist.m3u8

What did you do?
https://shaka-player-demo.appspot.com/demo/#asset=http://wilma.betalounge.com/mod/_definst_/mp3:lounge/2005/050910_dsl_de.mp3/playlist.m3u8;lang=es;build=uncompiled

What did you expect to happen?
mp3 to play

What actually happened?

**Player error
category: 4
code: 9009
data: Array []
handled: false
message: "Shaka Error MANIFEST.CONTENT_UNSUPPORTED_BY_BROWSER ()"
severity: 2

Warning: Cannot play media. No decoders for requested formats: audio/mpeg

Firefox is able to play the mp3 if you paste an mp3 directly in the url

Update 1: Firefox returns false for MediaSource.isTypeSupported("audio/mpeg")

Update 2: Looking further it appears firefox requires mp3 to be remuxed as mp4, is mux.js able to be used for this?
https://bugzilla.mozilla.org/show_bug.cgi?id=932516

[ismena]

@michellezhuogg
Do you happen to know whether mux.js can remuxe mp3 into mp4?

@joeyparrish
Would you like me to schedule this?

[joeyparrish]

I added it to the backlog for now. We will be doing v2.5 planning as soon as v2.4 comes out, but v2.4 is already too large.

[joeyparrish]

Part of this is Firefox's support, which we don't control. The other part is our own support of MP3, which is part of "containerless" format support, tracked in #2337.

I'll close this as a duplicate.

Duplicate of #2337