[ogg-dev] Re: [Speex-dev] Re: [xiph-rtp] Re: [Vorbis-dev] Proposal: An extension to rules all others

Silvia Pfeiffer silviapfeiffer1 at gmail.com
Wed Apr 18 14:22:06 PDT 2007

On 4/19/07, Ralph Giles <giles at xiph.org> wrote:
> Most of the core developers don't care what people name their files,
> so to be clear, we are arguing over whether xiph as an organization
> should endorse, implement and promote something besides .ogg as a
> recommended extension for Ogg container files.
> > .oga / .ogv  (new extensions, with .ogg remaining for legacy and corner
> >  case uses)
> .oga isn't strictly necessary, since the installed base assumes .ogg =>
> application/ogg => vorbis-in-ogg audio file, if it assumes anything.

I disagree - a lot of theora/vorbis files have been given the "ogg"
extension, too - it is already a very confusing world.

> Note that speex-in-ogg sometimes uses the .spx extension.
> > .ogg / .ogm (legacy extensions, possible drawback in not leaving
> >  room for corner cases and requiring existing files to be renamed.
> >  I got the impression the existing .ogm was something of a hack)
> .ogm has the advantage of being already in use. However, the vast
> majority of tools that recognize .ogm expect xvid+vorbis and do not
> handle theora+vorbis, so this would also cause user confusion.
> Thus from my point of view, .ogv is the best candidate.

I think if we as a community don't solve both the issues around MIME
type and file extension now, they will be solved for us - and we
potentially end in a much larger mess than we already are.

My suggestion is to use "ogg" as an extension along the same line of
argument as application/ogg as a MIME type - anything inside ogg can
be called this. And this inculdes the existing Ogg Vorbis and Ogg
Theora files. I still believe using the disposition parameter works,

.oga and audio/ogg for audio - covering spx, flac, and vorbis inside
ogg - this is to indicate which application to use and works along the
same line of the disposition parameter.

.ogv and video/ogg for video - covering theora with any audio codec inside ogg.

.spx and audio/speex+ogg for speex inside ogg

.flac and audio/flac+ogg for flac inside ogg (actually: are all .flac
extension files flac inside ogg?)

audio/vorbis for vorbis without a container as is needed for rtp/rtsp

audio/speex for speex without a container similarly

A few comments:
* I think we can have a generic scheme and more specific schemes to
make it easier for applications. E.g. speex in ogg could come as
".ogg", ".oga", or ".spx" depending on how specific you want to be. We
can of course suggest to users to go for the most specific extension
where possible. So, ".spx" would be used for speex-only inside ogg.
".oga" would be used e.g. for speex and vorbis multichannel inside
ogg, and ".ogg" would be used e.g. for speex and vorbis with MNG.

* I think using .oga for vorbis files in future alongside the less
specific .ogg is not a contradiction of our previous suggestion of
using .ogg - it is just more specific and both will continue to be

I suggest we start a wiki page to collate our findings and discussion.


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