High Efficiency Image File Format (HEIF) is a container format for individual images and image sequences. The standard covers multimedia files that can also include other media streams, such as timed text, audio and video. A HEIF image using High Efficiency Video Coding, HEVC, requires only about half the storage space as the equivalent quality JPEG. HEIF also supports animation, and is capable of storing more information than an animated GIF or APNG at a small fraction of the size.
HEIF files are a special case of the ISO Base Media File Format (ISOBMFF, ISO/IEC 14496-12), first defined in 2001 as a shared part of MP4 and JPEG 2000. Introduced in 2015, it was developed by the Moving Picture Experts Group (MPEG) and is defined as Part 12 within the MPEG-H media suite (ISO/IEC 23008-12).
HEIF was adopted by Apple in 2017 with the introduction of iOS 11, and support on other platforms is growing.
Apple was the first major adopter of the format in 2017 with the introduction of iOS 11 using HEIC variant.
On some systems, pictures stored in the HEIC format are converted automatically to the older JPEG format when they are sent outside of the system.
HEIF files can store the following types of data:
- Image items
- Storage of individual images, image properties and thumbnails.
- Image derivations
- Derived images enable non-destructive image editing, and are created on the fly by the rendering software using editing instructions stored separately in the HEIF file. These instructions (rectangular cropping, rotation by one, two or three quarter-turns, timed graphic overlays, etc.) and images are stored separately in the HEIF file, and describe specific transformations to be applied to the input images. The storage overhead of derived images is small.
- Image sequences
- Storage of multiple time-related and/or temporally predicted images (like a burst-photo shot or cinemagraph animation), their properties and thumbnails. Different prediction options can be used in order to exploit the temporal and spatial similarities between the images. Hence, file sizes can be drastically reduced when many images are stored in the same HEIF file.
- Auxiliary image items
- Storage of image data, such as an alpha plane or a depth map, which complements another image item. These data are not displayed as such, but used in various forms to complement another image item.
- Image metadata
- Storage of EXIF, XMP and similar metadata which accompany the images stored in the HEIF file.
As HEIF is a container format, it can contain still images and image sequences that are coded in different formats. The main filename extensions are .heif for still images and .heifs for sequences, which can both be used with any codec.
Apple supports playback of .heif for still image files and .heifs for image sequence files created on other devices that are encoded using any codec, provided that codec is supported by the operating system.
Generic HEIF image files are typically stored with filename extensions .heif, but they may use a different extension to indicate the specific codec used.
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.
HEIC: HEVC in HEIF
High Efficiency Video Coding (HEVC, ITU-T H.265) 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-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.)
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. Apple products, for instance, will only produce files with these extensions, which indicate clearly that the data went through HEVC encoding.
AVCI: AVC in HEIF
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, but will only generate .heic files.
AVIF: AV1 in HEIF
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 and HEIF
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.
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 and Mozilla's Firefox have experimental AVIF support. Facebook supports the upload of HEIC but converts to JPEG or WEBP on display.
- Nokia provides an open source Java HEIF decoder.
- The open source library "libheif" supports reading and writing HEIF files, as of version 1.8.0 both reading and writing HEIC and AVIF are supported.
- A free image codec called CopyTrans HEIC, available for Windows versions 7 through 10, supports opening HEIF files in Windows Photo Viewer without the Microsoft codec installed. (The Microsoft HEIC codec is only available for Windows 10, version 1803 and up in the Photos UWP app.)
- 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.
- macOS High Sierra and later (HEIC only) Since macOS Mojave, Apple uses HEIF in creating the Dynamic Desktop feature.
- iOS 11 and later (HEIC only)
- Android 9 (Pie) and later (HEIC), Android 10 (Q) and later (AVIF)
- Ubuntu 20.04 and later (HEIC)
As of May 2020, no browser supports HEIC natively. Both Chromium and Firefox have merged experimental support for AVIF in their source code.
Image editing software
- Adobe Lightroom (macOS High Sierra, iOS 11+, Windows 10, and Android 9+)
- Affinity Photo
- GIMP recognizes and treats HEIF files since version 2.10.2, released in May 2018.
- Zoner Photo Studio X
- Pixelmator (version 3.7 and above)
- 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. "We've moved on to HEIF files," Canon said in 2019.
- Qualcomm's latest Snapdragon SoCs (e.g. Snapdragon 865, Snapdragon 662) support 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.
HEIF itself is a container that may not be subject to additional royalty fees for commercial ISOBMFF licensees. Note however that Nokia also grants its patents on a royalty-free basis for non-commercial purposes. When containing images and image sequences encoded in a particular format (e.g. HEVC or AVC) its use becomes subject to the licensing of patents on the coding format.
- Better Portable Graphics (BPG) – another image file format using HEVC encoding, published by Fabrice Bellard in 2014
- Free Lossless Image Format (FLIF) – FOSS image format released in 2015, claiming to outperform PNG, WebP, BPG and JPEG 2000 for lossless encoding at least
- JPEG XL – another image format in development as potential successor to JPEG and JPEG 2000
- WebP – an image format based on the VP8 and VP9 video formats
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- ISO/IEC 23000-22. Multimedia application format (MPEG-A) — Part 22: Multi-image application format (MIAF), ISO/IEC MPEG
- Glenn Fleishman (26 June 2020). "What the HEIC? Apple's Highly Compressed Image Format Still Confuses". TidBITS.
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- "libheif is a ISO/IEC 23008-12:2017 HEIF file format decoder and encoder".
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- CopyTrans HEIC for Windows
- "Announcing Windows 10 Insider Preview Build 17123 for Fast Ring Subscribers". Retrieved 2018-03-16.
- Hollister, Sean (2017-06-05). "Apple answers iPhone storage woes with smaller photos, videos". CNET. CBS Interactive. Retrieved 2017-09-30.
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- "paint.net 4.2 is now available!". 2019-07-13. Retrieved 2019-07-13.
- "Krita 4.1 Release Notes". Retrieved 2018-11-19.
- "Zoner Photo Studio X brings support for the HEIF image format to Windows". DPReview. Retrieved 2018-03-20.
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- https://media.the-digital-picture.com/Information/Canon-EOS-1D-X-Mark-III-Still-Image-White-Paper.pdf page 45
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If there's one major downside to both HEVC and HEIF, it's that they're covered by patents that may need to be licensed for use in various apps and services.
- "Converting a JPEG to the new HEIF format". Retrieved 2017-07-04.
HEIF and HEVC are extensively covered by patents, which means there could be legal implications to implementing HEIF support, particularly in paid software or a hardware product.
- Ozer, Jan; Gill, Dror (2017-06-12). "Apple Endorses New Image Format, HEIF". Retrieved 2017-10-31.