MIME Types and File Extensions

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

• Ogg Opus profile
• Defined by https://tools.ietf.org/html/rfc7845

.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

• THIS FILE FORMAT IS DEPRECATED.
• Profile for audio in Annodex
• covers e.g. Vorbis, Speex, FLAC, Opus, Ghost, OggPCM inside Ogg with Skeleton and CMML

.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)