MIME Types and File Extensions: Difference between revisions

From XiphWiki
Jump to navigation Jump to search
(Changed STATUS and IMPLEMENTATION to be more human-readable. Merged DISCLAIMER.)
Line 1: Line 1:
STATUS: Work on RFCs and tools is starting now to reflect these policies. Use the correct file extensions straight away.
STATUS: Most of the below MIME types are not registered. Work have started on the required RFCs and software tools.


DISCLAIMER: currently, only application/ogg is a registered MIME type.  Registration for the others is being undertaken. During this process, the "x-" versions of these unregistered MIME types may be used.
IMPLEMENTATION: Use the correct file extensions straight away. See [[MIME-Migration]] for ecommendations and patches. Note the RFC encourage using a ‘x-’ prefix on all non‐registered MIME types.
 
IMPLEMENTATION recommendations and patches: see [[MIME-Migration]].


== .ogx - application/ogg ==
== .ogx - application/ogg ==

Revision as of 15:25, 14 September 2007

STATUS: Most of the below MIME types are not registered. Work have started on the required RFCs and software tools.

IMPLEMENTATION: Use the correct file extensions straight away. See MIME-Migration for ecommendations and patches. Note the RFC encourage using a ‘x-’ prefix on all non‐registered MIME types.

.ogx - application/ogg

  • Ogg Multiplex Profile (anything in Ogg)
  • can contain any logical bitstreams multiplexed together in an ogg container
  • will replace the .ogg extension from RFC 3534 http://www.ietf.org/rfc/rfc3534.txt
  • random multitrack files SHOULD contain a Skeleton track to identify all containing logical bitstreams
  • apps that identify a logical bitstream which they cannot decode SHOULD ignore it but MAY still decode the ones they can
  • thus, e.g. an annodex file can gracefully degrade to .ogx if an app cannot decode CMML and/or Skeleton
  • USE: application/ogg has been registered, so can be used immediately

.oga - audio/ogg

  • Ogg Audio Profile (audio in Ogg container)
  • Applications supporting .oga, .ogv SHOULD support decoding from muxed Ogg streams
  • Covers Ogg FLAC, Ghost, and OggPCM
  • Although they share the same MIME type, Vorbis and Speex use different file extensions.
  • May contain Ogg Skeleton and/or CMML logical bitstreams.
  • Vorbis and Speex may use .oga, but it is not the prefered method of distributing these files because of backwards-compatibility issues.

RATIONALE: This distinguishes audio-only files, using any of the Xiph audio codecs, from Vorbis I files (traditionally .ogg) which may not contain more than one logical bitstream.

.ogv - video/ogg

  • Ogg Video Profile (a/v in Ogg container)
  • apps supporting .oga, .ogv SHOULD support decoding from muxed Ogg streams
  • covers e.g. Theora, Theora + Vorbis, Theora + Speex, Theora + FLAC, Dirac + Vorbis, MNG + FLAC, OggUVS inside Ogg
  • This list is not exhaustive (for example, Dirac + FLAC is acceptable too)
  • May contain Ogg Skeleton and/or CMML logical bitstreams.

.ogg - audio/ogg

  • Ogg Vorbis I Profile
  • .ogg applies now for Vorbis I files only
  • .ogg has more recently also been used for Ogg FLAC and for Theora, too — these uses are deprecated now in favor of .oga and .ogv respectively
  • has been defined in RFC 3534 http://www.ietf.org/rfc/rfc3534.txt for application/ogg, so rfc 3534 will be re-defined

RATIONALE: .ogg has traditionally been used for Vorbis I files, in particular in HW players, hence it is kept for backwards-compatibility

.spx - audio/ogg

  • Ogg Speex Profile
  • .spx has traditionally been used for Speex files within Ogg and should be considered for backwards-compatibility

.flac - audio/flac

  • FLAC in native encapsulation format

.anx - application/annodex

  • Profile for multiplexed Ogg that includes a skeleton track and at least one CMML logical bitstream
  • apps that identify a logical bitstream which they cannot decode SHOULD ignore it but MAY still decode the ones they can
  • apps that come across an annodex file and cannot decode CMML and/or Skeleton, but can deal with the others SHOULD gracefully degrade by ignoring these

.axa - audio/annodex

.axv - video/annodex

  • Profile for video in Annodex
  • covers e.g. Theora, Theora + Vorbis, Theora + Speex, Theora + FLAC, Dirac + Vorbis, MNG + FLAC, OggUVS inside Ogg with Skeleton and CMML

.xspf - application/xspf+xml

  • Profile for XSPF
  • Covers XSPF, while being used through XML
  • Does not cover JSPF, which is XSPF but on JSON

Codec MIME types

Codecs need their own MIME types for streaming in RTP and to be used in multitrack ogg files using skeleton:

  • audio/vorbis for Vorbis without container
  • video/theora for Theora without container
  • audio/speex for Speex without container
  • audio/flac for FLAC without and in native container
  • text/cmml for CMML without container