What Are HEIF and HEIC and Why is Apple Using Them?

HEIF is better in every way a new file image format can be

New Loop and Bounce effects make every photo more expressive. Apple PR

Apple adopted a new standard image format called HEIF (High Efficiency Image Format) in 2017. It's calling its use of that file format 'HEIC' and, with iOS 11, replaced the file format called JPEG (pronounced Jay-Peg) with HEIF and the corresponding HEIC (High Efficiency Image Container).

Here's why it matters: the format stores images in better quality while taking up much less storage space.

Images Before HEIF

Developed in 1992, the JPEG format was a great success for what it was, but it was built at a time when computers just weren’t as capable as they are today.

HEIF is based on advanced video compression technology developed by the Motion Picture Experts Group, HVEC (also known as H.265). That’s why it is capable of carrying so much information.

How HEIF Applies To You

Here's where HEIF applies to the real world: the camera in the iPhone 7 can capture 10-bit color information, but the JPEG format can only capture color in 8-bit. That basically means the HEIF format supports transparency and can handle images in 16-bit. And get this: the HEIF image is around 50 percent smaller than the same image saved in JPEG format. That compressed image means you should be able to store twice as many images on your iPhone or other iOS device.

Another big advantage is that HEIF can carry lots of different kinds of information.

While JPEG can carry the data that comprises a single image, HEIF can carry both single images and sequences of them—it acts like a container. You can store multiple images, and can also place audio, depth of field information, image thumbnails and other information in there.

How Can Apple Use HEIC?

This use of HEIC as a container for images, videos, and image-related information means Apple can think about doing much more with your iOS cameras and images.

Apple’s iPhone 7’s Portrait Mode is a good example of how the company might work with this. Portrait Mode captures multiple versions of an image and stitches them together to create much better portraits at a much higher quality than JPEG.

The capacity to carry depth of field information inside the HEIC image container may enable Apple to use the compressed format as part of the augmented reality technologies it is working on. 

"The line between photos and videos is blurred, and a lot of what we capture is a combination of both of these assets," said Apple’s VP Software, Sebastien Marineau-Mes at WWDC.

How Do HEIF and HEIC Work?

Mac and iOS users installing iOS 11 and macOS High Sierra will automatically be moved to the new image format, but only the images they capture after they upgrade will be kept in this new format.

All your older images will be stored in their existing image format. 

When it comes to sharing images, Apple’s devices will simply convert HEIF pictures into JPEGs. You should not notice this transcoding take place. 

This is because Apple has provided HVEC video standard inside iPhone and iPad hardware since it first introduced those products. iPads, the iPhone 8 series and iPhone X can encode and decode images in the video format almost instantly. It is the same when handling HEIC.

This means that when you email an image, send it with an iMessage, or just work on it in an app that doesn’t possess HEIF support, your device will quietly convert it to JPEG in real-time and move it to HEIC.

As iOS and macOS users migrate to the new format you will see more and more images carrying the .heif filename extension, which signifies they are saved in the format.