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High Efficiency Image File Format

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High Efficiency Image File Format (HEIF)
Filename extension
.heif, .heic
Internet media typeimage/heif, image/heic, image/heif-sequence, image/heic-sequence
Uniform Type Identifier (UTI)public.heif, public.heic
Developed byMoving Picture Experts Group (MPEG)
Type of formatImage Container Format
StandardISO/IEC 23008-12
Websitehttp://mpeg.chiariglione.org/standards/mpeg-h/image-file-format

High Efficiency Image File Format (HEIF, often pronounced heef)[1][2][3][4] is a file format for individual images and image sequences. It was developed by the Moving Picture Experts Group (MPEG) and is defined by MPEG-H Part 12 (ISO/IEC 23008-12). The MPEG group claims that twice as much information can be stored in HEIF image as a JPEG one of the same size, even in better quality. 

The HEIF specification also defines the means of storing High Efficiency Video Codec (HEVC)-encoded intra images and HEVC-encoded image sequences in which inter prediction is applied in a constrained manner.

HEIF files are compatible with the ISO Base Media File Format (ISOBMFF, ISO/IEC 14496-12) and can also include other media streams, such as timed text and audio.

History

The requirements and main use cases of HEIF were defined in 2013.[5][6] The technical development of the specification took about 1.5 years and was finalized in summer 2015.[7]

In June 2017, Apple announced support for HEIF in macOS High Sierra and iOS 11 which were released in September 2017.[8][9][10]

Nokia supports the format and has released an open source JavaScript HEIF decoder on GitHub that works on a web browser.[11]

In March 2018, Android P and Microsoft Windows 10 (build 17123[12]) introduced support for HEIF.[13]

Use cases

Some usage scenarios that are facilitated by HEIF are described below:

Digital cameras and smartphones

To save storage space, HEIF-encapsulated HEVC-coded images can be used for compressing the full-resolution images while including lower-resolution JPEG copies for preview images and thumbnails.

Digital cameras[citation needed] and smartphones[citation needed] can use HEIF to achieve single-file packaging of burst photos, focal stacks, and exposure stacks. Similarly, simultaneously captured video and still images can be stored in the same HEIF file. HEIF also enables storage of any image collections into a single file, which can be shared easily.

Web pages and Internet-connected image applications

The picture element of HTML5.2 provides the capability of indicating multiple alternatives for the same image, out of which the web browser can select the one that best suits its purpose. A motivation for web pages and connected applications to start using HEIF is to reduce the web page and image content download times.

Image editing

HEIF includes the ability to efficiently store certain image transformations, including: [14]

  • Image Rotation: rotating the source image by 90, 180, or 270 degrees
  • Rectangular Cropping: cropping the source image according to a given cropping rectangle
  • Image Overlay: overlaying any number of input images in indicated order and locations onto the source image canvas.

These operations are stored in the file as instructions to be applied by the rendering software, and can be applied, modified, or removed without affecting the source image. (Applying such operations to JPEG and GIF images usually require that the original image be re-encoded after the operations are applied, which can amplify compression artifacts. See Lossy compression#Transcoding and editing.)

Additionally, HEIF introduces a framework for other non-destructive editing operations which can be specified by external specifications.

Once these operations are applied, the result is known as a "derived image".

Features

HEIF files can store the following types of data:[15]

  • Image Items: storage of individual images, image properties and thumbnail(s).
  • 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 90, 180, or 270 degrees, 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 even when tens of images are stored in the same HEIF file.
  • Auxiliary Image Items: storage of image data which complements another image item. An alpha plane or a depth map are examples for such images. 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.

HEVC Image File Format

  • HEVC image players are required to support rectangular cropping and rotation by 90, 180, and 270 degrees. The primary use case for the mandatory support for rotation by 90 degrees is for images where the camera orientation is incorrectly detected or concluded. This requirement makes it possible to manually adjust the image or image sequence orientation afterwards without the need for re-encoding the image or image sequence. Similarly, cropping may be useful to enable post-shooting zoom without the need for re-encoding. As rotation by 90, 180, or 270 degrees as well as cropping are mandatory for all HEVC image file players, it is guaranteed that re-encoding is not required to carry out these operations. (The HEVC file format, however, does include the option to store pre-derived images.[16])
  • 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.

Implementation

As HEIF is a container format, it can contain still images and image sequences (where a file contains more than one single image) that are coded in different formats, currently these include HEVC and H.264/MPEG-4 AVC (and JPEG for thumbnail/secondary images), though other coding formats may be added in the future. The two main filename extensions are .heif or .heic, along with a less common .avci that is typically used for H.264/AVC encoded files.

In Apple's implementation, for single images they have chosen the latter .heic filename extension (.heics for image sequence files)[17] as the only one they will produce for photos, which indicates clearly that it went through HEVC encoding.[18] However, they will support playback of both H.264/AVC encoded .avci files (.avcs for image sequence files),[17] and also .heif files (.heifs for image sequence files)[17] created on other devices that are encoded using any codec, provided that codec is supported by them.[19]

Patent licensing

HEIF itself is a container, and when containing images and image sequences encoded in a particular format (e.g., HEVC or H.264/AVC), its use becomes subject to the licensing of patents on the coding format.[20][21][22] Generally, lawful use of a patented invention requires the patent holder's permission in countries where the patent is in force (see patent infringement).

Related standards

  • Advanced Video Coding (AVC, aka H.264) – an older encoding format for video and images, first standardized in 2003
  • High Efficiency Video Coding (HEVC, aka H.265) – an encoding format for video and images, first standardized in 2013
  • ISO Base Media File Format – a file format standard that covers HEIF and other similarly formatted multimedia files, first standardized in 2001
  • MPEG-H – a suite of standards that includes HEIF and HEVC

See also

References

  1. ^ Ward, Mikey (September 21, 2017). "Your photos just had a massive change with iOS 11. Here's what happened". Popular Science. Retrieved November 22, 2017.
  2. ^ Ward, Mikey (June 8, 2017). "New HEVC & HEIF Media Formats: What You Need to Know". Big Nerd Ranch. Retrieved November 22, 2017.
  3. ^ Turnquist, Erik (June 9, 2017). "Working with HEIF and HEVC". Apple. Event occurs at 0:00:01. Retrieved November 20, 2017. My name is Erik Turnquist and today Brad and I are going to talk about working with HEIF (heef) and HEVC...
  4. ^ Richie, Rene (November 14, 2017). "MacBreak Weekly 584 - A Free Pass From Darwin". MacBreak Weekly. Event occurs at 1:54:20. Retrieved November 20, 2017. ...you can tap between JPEG and now HEIF (heef) and RAW...
  5. ^ "Requirements for still image coding using HEVC | MPEG". mpeg.chiariglione.org. Retrieved 2015-11-25.
  6. ^ "Requirements for HEVC image sequences | MPEG". mpeg.chiariglione.org. Retrieved 2015-11-25.
  7. ^ "Evidence motivates MPEG to launch new standardization effort for HDR".
  8. ^ Hollister, Sean (June 5, 2017). "Apple answers iPhone storage woes with smaller photos, videos". CNET. CBS Interactive. Retrieved September 30, 2017.
  9. ^ Snell, Jason (September 20, 2017). "iOS 11: HEVC, HEIF, and what you need to know about these new video and photo formats". Macworld. Retrieved September 30, 2017.
  10. ^ Shu, Lee (September 19, 2017). "Here's what HEIF and HEVC are, and why they'll improve your iPhone with iOS 11". Digital Trends. Retrieved September 30, 2017.
  11. ^ http://blog.jpegmini.com/move-over-jpeg-here-comes-heif/
  12. ^ "Announcing Windows 10 Insider Preview Build 17123 for Fast Ring Subscribers". Retrieved 2018-03-16.
  13. ^ "Previewing Android P". Android Developers Blog. Retrieved 2018-03-07.
  14. ^ "Move over JPEG, Here Comes HEIF! | JPEGmini Blog". blog.jpegmini.com. Retrieved 2018-02-01.
  15. ^ M. M. Hannuksela; E. B. Aksu; V. K. Malamal Vadakital; J. Lainema. "Overview of the High Efficiency Image File Format". JCT-VC document JCTVC-V0072, Oct. 2015.
  16. ^ "HEIF Technical Information - High Efficiency Image File Format". nokiatech.github.io. Images in HEIF Files. Retrieved 2018-02-01. {{cite web}}: Cite has empty unknown parameter: |dead-url= (help)
  17. ^ a b c "High Efficiency Image File Format". Apple. June 2017. Event occurs at 0:09:26. Retrieved November 22, 2017.
  18. ^ Shankland, Stephen (June 16, 2017). "How Apple is squeezing more photos into your iPhone – FAQ: Apple's newest iPhone software attempts to move the world out of the JPEG era". CNET. Retrieved November 21, 2017.
  19. ^ "Introducing HEIF and HEVC". Apple. June 6, 2017. Event occurs at 0:13:47. Retrieved November 22, 2017.
  20. ^ "macOS High Sierra tech preview: A quick look at the stuff you can't see". 2017-06-19. Retrieved 4 July 2017. 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.
  21. ^ "Converting a JPEG to the new HEIF format". Retrieved 4 July 2017. 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.
  22. ^ Jan Ozer; Dror Gill (12 June 2017). "Apple Endorses New Image Format, HEIF". Retrieved 31 October 2017.
  23. ^ "Apple wants to shrink your photos, but a new format from Google and Mozilla could go even farther". CNET. 2018-01-19. Retrieved 2018-02-01.

External links

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