High Efficiency Image File Format

The Multi-Image Application Format (MIAF) is a restricted subset of HEIF specified as part of MPEG-A. It defines a set of additional constraints to simplify format options, specific alpha plane formats, profiles and levels as well as metadata formats and brands, and rules for how to extend the format.[9]

High Efficiency Video Coding (HEVC, ITU-T H.265)[10] is an encoding format for graphic data, first standardized in 2013. It is the primarily used and implied default codec for HEIF as specified in the normative Annex B to ISO/IEC 23008-12 HEVC Image File Format.

While not introduced formally in the standard, the acronym HEIC (High-Efficiency Image Container) is used as a brand and in the MIME subtypes image/heic and image/heic-sequence. If the content conforms to certain HEVC profiles, more specific brands can be used: HEIX for Main 10 of HEVC, HEIM for (Multiview) Main profile and HEIS for (Scalable) Main (10) profile of L-HEVC.

The variation of HEIF used in Apple products exclusively uses HEVC compression technology and is known as HEIC. A HEIC photo takes up about half the space of an equivalent quality JPEG file, and meets many next-generation photographic needs. The initial HEIF specification already defined the means of storing HEVC-encoded intra images (i-frames) and HEVC-encoded image sequences in which inter prediction is applied in a constrained manner.

HEVC image players are required to support rectangular cropping and rotation by one, two and three quarter-turns. The primary use case for the mandatory support for rotation by 90 degrees is for images where the camera orientation is incorrectly detected or inferred. The rotation requirement makes it possible to manually adjust the orientation of a still image or an image sequence without needing to re-encode it. Cropping enables the image to be re-framed without re-encoding. The HEVC file format also includes the option to store pre-derived images.[11])

Samples in image sequence tracks must be either intra-coded images or inter-picture predicted images with reference to only intra-coded images. These constraints of inter-picture prediction reduce the decoding latency for accessing any particular image within an HEVC image sequence track.

The .heic and .heics file name extensions are conventionally used for HEVC-coded HEIF files.[12] Apple products, for instance,[7] will only produce files with these extensions, which indicate clearly that the data went through HEVC encoding.[1]

Advanced Video Coding (AVC, ITU-T H.264) is an older encoding format for video and images, first standardized in 2003. It is also specified as a codec to be supported in HEIF in normative Annex 5 to ISO/IEC 23008-12. The registered MIME types are image/avci for still images and image/avcs for sequences. The format is simply known as AVCI.

Apple products support playback of AVC-encoded .avci still image files and .avcs image sequence files,[7] but will only generate .heic files.

AV1 is a video encoding format that is intended to be royalty free developed by the Alliance for Open Media (AOMedia). AV1 Image File Format (AVIF) is an image format based on this codec.[13]

The registered MIME types are image/avif for still images which usually carry an .avif file name extension and image/avif-sequence for sequences which use .avifs file name extension. This may be confusable with the classic AVI Windows multimedia format which typically uses .avi.

JPEG is the most commonly used and best supported lossy image format, first released in 1992 by ITU-T and ISO/IEC. Although Annex H to ISO/IEC 23008-12 specifies JPEG (and indirectly Motion JPEG) as a possible format for HEIF image data, it is used only for thumbnails and other secondary images. Therefore neither a dedicated MIME subtype nor a special file extension is available.

JPEG 2000 also uses ISOBMFF, but in a way incompatible with HEIF, while JPEG XR uses a TIFF-based container format. Neither of them is currently formally specified as an image codec for use within HEIF.

In 2017, Apple announced that it would adopt HEIC as the default image format in its new operating systems, gradually replacing JPEG.[14]

Both AVIF and HEIF are currently being considered as possible replacements for the universal JPEG format because, among other technical contributions, both can reduce file size by about 50% while maintaining equivalent quality. As of May 2020, there is no native browser support for HEIF, while both Google's Chromium[15] and Mozilla's Firefox[16] have experimental AVIF support. Facebook supports the upload of HEIC but converts to JPEG or WEBP on display.[17]

• Windows 10 version 1803 and later (HEIC), version 1903 and later (AVIF). A small amount of money is charged for the use of the HEVC codec, whereas support for the generic HEIF format and the AVC and AV1 extensions are free.[21]
• macOS High Sierra and later (HEIC only)[22] Since macOS Mojave, Apple uses HEIF in creating the Dynamic Desktop feature.[23]
• iOS 11 and later (HEIC only)[24][2]
• Android 9 (Pie) and later (HEIC), Android 10 (Q) and later (AVIF)[25][26]
• Ubuntu 20.04 and later (HEIC)[27]

As of May 2020, no browser supports HEIC natively.[28] Both Chromium and Firefox have merged experimental support for AVIF in their source code.

• Adobe Lightroom[29] (macOS High Sierra, iOS 11+, Windows 10, and Android 9+)
• Adobe Photoshop[30]
• Affinity Photo
• GIMP recognizes and treats HEIF files since version 2.10.2, released in May 2018.[31][32]
• Paint.NET[33]
• ImageMagick
• Krita[34]
• Zoner Photo Studio X[35][36]
• Pixelmator[37] (version 3.7 and above)
• GraphicConverter

• The Canon EOS-1D X Mark III, Canon EOS R5, and Canon EOS R6 cameras are using the HEIF format, capturing images with 10-bit precision with high dynamic range using the PQ tone curve, with the file extension .hif.[38][39] "We've moved on to HEIF files," Canon said in 2019.[40]
• The Sony α1 offers capturing images in 10-bit HEIF format.[41]
• Qualcomm's latest Snapdragon SoCs (e.g. Snapdragon 865,[42] Snapdragon 662[43]) support the HEIC format.

• During May 2020, online Advanced Placement exams allowed students to submit photos of handwritten responses. Because the website was unable to process HEIF images, students whose phones defaulted to this image format were considered to have not submitted any response and often failed to complete the exam. College Board, which administers the exams, later provided a system for users to submit photos of answers via e-mail. Because the iOS Mail app automatically converts HEIF images to JPEG, this mitigated the problem.[44]