(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