What Is HEIF and Will It Replace JPEG?
There is been a lot of hype surrounding HEIF, a new image format that some say is poised to replace longtime standards like JPEG and GIF. What's so different about high efficiency image files? This guide will cover the pros and cons of this new way of viewing photos.
What is HEIF?
In summer 2017, Apple announced its plans to adopt the high efficiency image file format, or HEIF, as its standard format for all images going forward. This new format boasts better compression than old standards like JPG, PNG and GIF, which results in much smaller file sizes. Apple did not invent the format; it's based on a technology called high efficiency video coding, or HEVC, which was created by the Motion Picture Experts Group. HEIF files also support metadata and thumbnails as well as unique features like non-destructive editing.
Apple's HEIF images have the extension HEIC, which stands for high efficiency image container - HEIF and HEIC are often used interchangeably. Starting with the iOS 11, users will be able to take pictures in either HEIF mode or JPEG mode.
The massive data storage savings come with a very slight reduction in quality. Although HEIC photos are technically capable of capturing a broader range of colors, many people have noticed that low-light shots especially tend to be less detailed than their JPEG counterparts. Nonetheless, the difference is usually negligible enough to be worth the trade-off.
If you're using 4K mode on your iPhone 8 or iPhone X, photos will automatically be saved as HEIC files, which is fine for most purposes. If having the highest possible image quality is important to you, and you've got plenty of storage space, then you might want to stick with JPEG. Otherwise, you might as well embrace the newer format.
Transferring HEIC files
Aside from slightly lower image quality, one of the biggest barriers to making HEIF a standard is its lack of widespread support. Because the technology is covered by a patent, implementing support requires obtaining the rights from its creators, which is something that few developers have yet to do. For example, no browsers currently support the format. Therefore, HEIC files are still automatically converted to JPEG files when imported non-supporting cloud services.
To avoid auto-conversion, you can go into your iCloud settings and switch the "Transfer to Mac or PC" option to "Keep originals;" however, if you import HEIC files from AirDrop, they will auto-convert to JPEG anyway. Files converted from HEIF will maintain their inferior quality, yet they will be just as large as regular JPEG files.
The easiest way to avoid conversion is to import your image files from iCloud.com when possible. The HEIF format is especially recommended for images stored on external drives due to their compact file sizes. Just keep in mind that AirDrop will increase the file size even if you're importing images onto a device that supports HEIC files. Until HEIC files become more widely supported, Apple will maintain the auto-conversion feature, and users will have to work around it.
Converting JPEG to HEIF
We've covered converting HEIC files to JPEG files, but what if you want to do the inverse? It's a bit more complicated but entirely possible. This involved using FFmpeg and building the HEIF file yourself.
A GitHub user has written a detailed tutorial on how to convert JPEG images to HEIF images. Once you're done converting the image, you can also use his HEIF image viewer at the bottom of the page to view the image you just converted.
The benefits of HEIF
Thanks to improved compression, HEIF images can be encoded and decoded swiftly with little cost to the system. This means that images load faster and take up less space on a server. Unlike the JPEG format, which only supports still images, HEIC files can contain a sequence of images just like a GIF file. HEIC files also support 4K, 3D, and transparency, and they can be rotated or cropped with ease. Most edits can be undone at any time.
For the immediate future, HEIF images will be exclusive to iOS 11, tvOS 11 and macOS High Sierra, but Apple devices will automatically convert HEIC files to another format when users share them with non-compatible apps.
Since HEIC files are containers, they are capable of storing different types of data including:
- Individual images along with properties and thumbnails.
- Image derivations, which get generated during run-time.
- Image sequences made up of multiple time-related or temporally predicted images such as photo bursts and cinemagraphs.
- Auxiliary data that complements image items such as alpha planes, depth maps and even audio.
- Metadata including EXIF and XMP information related to the images in the HEIC file.
The HEIF format has numerous practical applications for users and developers. For example:
- It allows digital cameras and smartphones to store burst photos, focal stacks and exposure stacks in a single package.
- Simultaneously captured video and still images can also reside in the same file.
- HEIC files can be paired with the HTML5 picture element, which lets developers designate multiple alternatives for a web page image.
- Use of HEIC files can drastically cut web page load times since there is less data to download.
- Thanks to non-destructive editing operations, alterations like changes in image orientation and cropping don't require the image to be encoded again. This feature allows image editing applications to store multiple derivations of an image within the same file.
As soon as Apple users upgrade to iOS 11 or macOS High Sierra, HEIC will become the new default file format for captured photos; however, older pictures will remain in their original formats. While the HEVC video standard has been present in iPhones and iPads from the beginning, you must have iOS 11 or macOS High Sierra installed in order to view and edit HEIC files. Apple's iPhone 8 and iPhone X are capable of encoding and decoding images almost instantaneously, which is what allows devices to quickly convert HEIC files into a more friendly format when users share their pictures.
How much space do HEIF images and HEVC videos save?
Dozens of bloggers have conducted their own experiments comparing HEIC to JPEG and HEVC to H.264. Christian over at idownloadblog.com found that HEVC videos are around 40 percent smaller than H.264 files, and HEIC files are approximately 50 percent smaller than JPEG files.
Using the default "High Efficiency" setting on an iPhone 7 Plus, he snapped eight photos and recorded a 60-second 4K video at 60 FPS. He then converted them all to JPEG and H.264 files. The size differences were as follows:
The size differences between each image and video are quite substantial. In every case, the HEIC images turned out to be less than half the size of the original JPGs. These size savings make for much faster delivery and greatly increases the number of image and video files one can store on their device.
The JPEG format is still incredibly popular and well integrated into many devices, systems, etc. Nonetheless, HEIF shows promise in that it allows images to be about twice as small as a regular JPGs with minimal quality loss. When compared to JPEGs, any differences in image quality are inconsequential in light of the file size benefits. For now at least, some Apple users will be able to store more images and videos on their iPhones while still having more space left over for other apps. As the evolution of 4K and 3D technologies progress, the hurdle of reducing file sizes and improving delivery speeds will become increasingly important and so far, HEIF seems to be on the right course to alleviate those issues.