MIME Types and File Extensions

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STATUS: RFC 5334 encapsulates the below listed policies. More details are here, which also include a specification of the codecs parameter of the MIME types. Use the correct file extensions straight away.


IMPLEMENTATION recommendations and patches: see MIME-Migration.

.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 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

.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)
  • SHOULD contain a Skeleton track and/or MAY contain a CMML logical bitstream.

.opus - audio/ogg

.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, Opus and Speex use different file extensions.
  • SHOULD contain a Skeleton logical bitstream.
  • Vorbis and Speex may use .oga, but it is not the prefered method of distributing these files because of backwards-compatibility issues.

.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
  • random multitrack files MUST 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

.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

  • THIS FILE FORMAT IS DEPRECATED.
  • 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

  • THIS FILE FORMAT IS DEPRECATED.
  • 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

Ogg Kate files - application/kate

  • Binary representation of Kate encapsulated in Ogg
  • may have a skeleton
  • can be used to identify the mime type of the track itself (e.g. in skeleton)
  • uses .ogx extension when in a file by itself
  • is subdued by the dominant mime type if in a audio or video file to become audio/ogg or video/ogg

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
  • audio/opus for Opus without container
  • text/cmml for CMML without container
  • application/kate for the textual representation of Kate (.kate files)
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