(registered 2018-07-30, last updated 2018-08-09)

MIME media type name: image

MIME subtype name: heif-sequence, heic-sequence

   The semantics of the subtypes are as follows:

   heif-sequence: High efficiency image file containing one or more 
      image sequences using any coding format

   heic-sequence: High efficiency image file containing one or more 
      HEVC coded image sequences

   The use of subtype values is constrained as follows: 

   The MIME subtype name may be 'heic-sequence' only if the file 
   conforms to the requirements of the 'hevc', 'hevx', 'hevm', or 
   'hevs' brand, and contains that brand as a compatible brand. The 
   MIME subtype name may be 'heif-sequence' only if the file conforms 
   to the requirements of the 'msf1' brand, and contains that brand 
   as a compatible brand. (A brand in the file header identifies a 
   specific profile of a more general format.)

Required parameters: none

Optional parameters:

   profiles: Specified by RFC 6381 and its successors.

   codecs: Specified by RFC 6381 and its successors for files 
      conforming to specifications derived from ISO/IEC 14496-12. 
      Note that for HEVC, the format of a list item included in the 
      value of the codecs parameter is specified in ISO/IEC 14496-15.
      When the codecs parameter is present, the first list item 
      should represent a track having the handler type 'pict'. Other 
      list items represent other tracks.

   lhevcptl: For multi-layer image items, specifies the decoding 
      capabilities required for different combinations of layers and 
      temporal sub-layers; the syntax and semantics specific to HEVC 
      and are formally specified by the lhevcptl optional MIME 
      parameter in ISO/IEC 14496-15 for the L-HEVC sample entry 
      types. Informatively, the syntax is BLInternal, ListItem1(, 
      ListItemN)*, where 

      BLInternal is 0 or 1; 
      each Listitem has the structure 
         OlsIdx.MaxTid.ProfileTierLevel1(.ProfileTierLevelN)*
      and
      OlsIdx and MaxTid are integers
      ProfileTierLevelX is the substring specified for any HEVC 
         sample-entry for the codecs parameter

   dependencies: as specified for the dependencies optional MIME 
      parameter of image/heif and image/heic MIME types.

Encoding considerations: as for video/mp4

Security considerations: See section 4 of RFC 4337 and section 7 of 
   RFC 6381. This format does not supply integrity or confidentiality 
   protection and so they are applied externally when needed. The 
   security considerations of URLs are discussed in RFC 3986.

Interoperability considerations: Interoperably deployed in reference 
   code available from ISO, Javascript code from Nokia labs, in 
   open-source in MP4Box and various other implementations.

Published specification: ISO/IEC 23008-12, available as a Publicly 
   Available Standard at 
   http://standards.iso.org/ittf/PubliclyAvailableStandards/index.html

Applications: Multimedia, Imaging, Pictures

Fragment identifier considerations: Fragment identifiers are 
   specified in Annex L of ISO/IEC 14496-12, available as a Publicly 
   Available Standard at 
   http://standards.iso.org/ittf/PubliclyAvailableStandards/index.html

Additional information:

   Magic number(s): none
   File extension(s): heifs (for subtype heif-sequence), heics (for 
      subtype heic-sequence), hif (for subtypes heif-sequence and 
      heic-sequence)
   Macintosh File Type Code(s): None

Person to contact for info: David Singer, singer&apple.com

Intended usage: Common

Author/Change controller: David Singer, ISO/IEC/JTC1/SC29/WG11 file 
   format chair