HEIF (High Efficiency Image File Format) is the lossy image (and animation?) format defined by MPEG-H Part 12 (ISO/IEC 23008-12).
[This section contains educated guesses, and may be incorrect.]
The standard apparently defines:
- A still image ("image collection") container format, based on boxes/atoms format, with brand
mif1. It uses some elements from ISO-BMFF (though note that still image formats cannot be technically valid ISO-BMFF).
- An animated image ("image sequence") container format, with brand
msf1. This might qualify as valid ISO-BMFF.
- An image compression scheme, with brand
- Various other compression schemes for use in the above containers, for example based on AVC or JPEG.
Some or all files that use
heic compression should use file extension .heic. Other files may use .heif.
Based on source code and sample files, it usually uses the brands
heic. Some files may use other brands, such as
- Some of the links in this forum post might still work
- Wikipedia: High Efficiency Image File Format
- HEIF information from the MPEG website
- HEIF information from Nokia Technologies
- ISO/IEC 23008-12 (not free to download)
- How Apple is squeezing more photos into your iPhone
See also MPEG-H#Links.