HEIFAVIF

HEIFAVIF is not an officially defined image format. The term is used informally to describe the relationship between the High Efficiency Image File Format (HEIF) and the AVIF image format. In many discussions, AVIF images are described as being stored within the HEIF container, or as part of the HEIF ecosystem, hence the combined shorthand.

HEIF is a standardized container format defined in ISO/IEC 23008-12. It can store a single image, image sequences, and metadata in a compact, feature-rich structure. Historically, HEIF images are associated with the HEVC (H.265) codec, but the container is codec-agnostic and may house other encodings as well.

AVIF is an image format defined by the Alliance for Open Media. It uses the AV1 video codec to encode still images and is stored in the ISO Base Media File Format. AVIF files typically use the avif brand and extension and are designed to provide strong compression, HDR support, and alpha channels.

Because AVIF is implemented inside the ISOBMFF container, AVIF images can be packaged in HEIF-compatible files and managed by HEIF tooling. As a result, AVIF is often described as part of the HEIF ecosystem, and some software treats AVIF and HEIF as overlapping formats. However, HEIFAVIF is not a separate standard; its meaning depends on context and often reflects practical packaging choices rather than a new specification.

AVIF has gained broad browser support and is widely used on the web, while HEIF support varies by platform and application due to licensing considerations around codecs like HEVC. AVIF’s royalty-free encoding with AV1 has contributed to its adoption. Tools such as libheif and libavif enable creation and decoding, facilitating interoperability between markets and devices.