From Just Solve the File Format Problem
HEIF (High Efficiency Image File Format) is the lossy image (and animation?) format defined by MPEG-H Part 12 (ISO/IEC 23008-12).
Based on draft specifications, it uses the brands
- 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.