1375409 - Can't play a webm file in https://github.com/webcompat/web-bugs/issues/7340

Status: RESOLVED INVALID

(Core :: Audio/Video: Playback, enhancement)

Description

[Alfredo Yang (:alfredo)]

https://github.com/webcompat/web-bugs/issues/7340

Comment 1

[Alfredo Yang (:alfredo)]

Its EMBL doctype is 'matroska'; it should be 'webm' according to [1]. In libnestegg, it fails at [2]. Chrome accepts this doctype.

I'm not sure about this.
I think :kinetik should have better judgment on it than me.


[1] http://www.webmproject.org/docs/container/
[2] https://dxr.mozilla.org/mozilla-central/rev/b1b9129838ade91684574f42219b2010928d7db4/media/libnestegg/src/nestegg.c#2118

Comment 2

[Matthew Gregan [:kinetik]]

I think at the formation of the WebM fork of Matroska there was some agreement to only accept the "webm" doctype for simplicity (although looking at the WebM spec via archive.org shows the wording around doctypes has always been the same).  As it stands now, Chrome accepts these files, Firefox doesn't, and the WebM spec implies that demuxers need to handle non-"webm" doctypes.

Having said that, there's another issue with this file that prevents it from being a valid WebM file, which is that the audio track is of type A_AAC, and the only permitted audio codec types in WebM are A_VORBIS and A_OPUS (although this is ambiguous in the spec, since the codecs are listed by their common names in the Naming section, but the Guidelines has A_VORBIS/A_OPUS listed as SHOULD in the demuxer/muxer section).

Without evidence of a large(r) number of files affected by this, rejecting this particular file seems like a reasonable approach.

Comment 3

[Alfredo Yang (:alfredo)]

(In reply to Matthew Gregan [:kinetik] from comment #2)
> I think at the formation of the WebM fork of Matroska there was some
> agreement to only accept the "webm" doctype for simplicity (although looking
> at the WebM spec via archive.org shows the wording around doctypes has
> always been the same).  As it stands now, Chrome accepts these files,
> Firefox doesn't, and the WebM spec implies that demuxers need to handle
> non-"webm" doctypes.
> 
> Having said that, there's another issue with this file that prevents it from
> being a valid WebM file, which is that the audio track is of type A_AAC, and
> the only permitted audio codec types in WebM are A_VORBIS and A_OPUS
> (although this is ambiguous in the spec, since the codecs are listed by
> their common names in the Naming section, but the Guidelines has
> A_VORBIS/A_OPUS listed as SHOULD in the demuxer/muxer section).
> 
> Without evidence of a large(r) number of files affected by this, rejecting
> this particular file seems like a reasonable approach.

Thanks for the comment.