MIME Types and File Extensions

From XiphWiki

Revision as of 21:23, 2 September 2007 by Silvia (Talk | contribs)
Jump to: navigation, search

STATUS: Work on RFCs and tools is starting now to reflect these policies. Use the correct file extensions straight away.

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 should be used.

IMPLEMENTATION recommendations and patches: see MIME-Migration.

Contents

.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)
  • apps 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.

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 - application/flac

  • FLAC in native encapsulation format

I believe application/flac was used in analogy to application/ogg, and has never actually be registered. This might be an opportunity to register the more correct audio/flac. I don't know if an imformational RFC on the flac format needs to be published for that to happen. --rillian.

.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 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 container, but extra FLAC Ogg header (?)
  • text/cmml for CMML without container
Personal tools


Main Page

Xiph.Org Projects

Audio—

Video—

Text—

Container—

Streaming—