A new image file format, High Efficiency Image Format (HEIF) is being introduced, with the first camera to use it, the Canon EOS-1D X Mark III paving the way for what is being touted as ‘JPEG’s replacement’.
The structure of HEIF files.
HEIF hit the headlines at Apple’s 2017 developer conference when the company announced it was moving to use it for image capture and storage across its product platforms. Interestingly, this new file format was not developed by Apple but instead by the Moving Picture Experts Group (MPEG), and it’s a container rather than a format. The container is very flexible and is capable of storing multiple images, audio, depth information, animation and video sequences, metadata and thumbnails. JPEG, in contrast, can only carry data for one photo.
The HEIF specification also defines the High Efficiency Video Codec (HEVC)-encoded storage system for intra-images and HEVC-encoded video image sequences in which inter-prediction is applied. Interestingly, Apple also uses it for still images compressed with the HEVC (H.265) codec. The file extension *.heic is most commonly used, but HEIC files may also appear as *.HEIF files.
File compression has become increasingly important in recent years due to the introduction of 4K video recording and a move to higher resolution in many digital cameras. Introduced in 2015, HEVC was developed primarily to compress those huge video streams. After 25 years, JPEG is showing its limitations. For starters, it’s an 8-bit format and high compression levels tend to produce obvious reductions in picture quality.
HEIF claims a two to one increase in compression over JPEG at similar quality levels. According to information provided by Canon in a White Paper released simultaneously with the announcement of the EOS-1D X Mark III, typical file sizes produced from the new camera are as follows:
RAW images — approx. 22.1MB
C-RAW images — approx. 13.1 MB
HEIF images — approx. 7.6 MB
JPEG images (full-resolution, Large/Fine) — approx. 7.6 MB
Both JPEG and HEIF images can be set to 10 levels of compression, in-camera. But HEIF images can be encoded and decoded much faster than JPEGs, without overloading the processing system or depleting the battery. Canon sees users of the EOS-1D X Mark III selecting JPEG files for on-screen viewing, HEIF images for large-screen HDR displays and RAW images for publication or printed output.
As a file format HEIF is also good for editing. By supporting colour depths of up to 16 bits, it can record the extended dynamic range delivered by a camera’s 10-bit colour output, thereby recording more highlight and shadow details than equivalent JPEGs and solving issues with banding in photos resulting from JPEG compression.
Since 2017, HEIF files have been supported by both iOS (iOS 11 and later) and macOS (macOS High Sierra and later) operating systems and can be viewed with Apple Preview and Apple Live Photos and iOS Photos. But files are automatically converted to JPEGs if they are shared on social networks or exported to older Apple systems and other platforms.
HEIF files can be opened by Windows 10 (version 1803 and later) devices but it requires the installation of the HEIF Image and HEVC Video Extensions from the Microsoft Store. Windows users can also install CopyTrans HEIC for Windows, which allows programs like Windows Explorer and Windows Photo Viewer, to open HEIF files as JPEGs. HEIF files can also be opened in Windows using Zoner Photo Studio X.
To date, none of the popular web browsers, such as Google Chrome, Mozilla Firefox, Microsoft Edge and Apple’s Safari, includes native support for HEIF, although it IS supported by Android Pie and later versions. However, HEIF is compatible with most image-editing software titles, including Adobe’s Lightroom and Camera Raw, Affinity Photo, GIMP, Paint.NET, Pixelmator, GraphicConverter and ImageMagick.
Problems can also occur if you want to print HEIF images from original files. Epson has not yet introduced direct HEIF support into any of its professional or enthusiast printers and as far as we are aware Canon has not released printer drivers that will print directly from a HEIF file (although that might change as more photographers upgrade to the EOS-1D X Mark III. Although some printing kiosks can read the format all commercial printers and kiosks require HEIF files to be converted into JPEGs before they can be printed,
Will HEIF take over?
The introduction of HEIF is unlikely to eliminate JPEG from our lives; it is just too firmly entrenched. Back at the turn of the 21st century, JPEG 2000 (JP2) was being touted as a ‘JPEG replacement’ because it was more flexible, being able to handle video files as well as still image and offering both lossless and lossy compression in a single compression architecture. It was also capable of supporting high bit depths, such as 16- and 32-bit floating point pixel images, better able to handle colour-space information and metadata as well as being more robust to bit errors introduced by noisy communication channels.
So why didn’t JPEG 2000 take off?
Despite its many advantages, JPEG 2000 came with a few critical drawbacks. The first was it required more memory, a significant hurdle to overcome back in 2000 when the average computer provided around 64 MB of memory. Camera manufacturers were also hesitant to accept the format and waited until it was widely adopted, thereby impeding its growth. Finally, no web browser, image editor, paint program or office application has JPEG 2000 as its native file format; they all use JPEG.
It remains to be seen whether HEIF will supplant JPEG as the preferred ‘universal’ file format. It certainly has some substantial advantages in terms of greater flexibility, higher image quality, smaller files and faster processing. But JPEG has the advantage of ubiquity, which will make it hard to displace.
Right now, we live in a JPEG world.
In a White Paper published at the launch of the EOS-1D X Mark III, Canon notes:
HEIF files are intended to be viewed on HDR-compliant displays and monitors. When viewed on compliant displays, a wider tonal range is visible — without need to edit or process the file. Be aware that many types of computer viewing software are not compatible with HEIF files, as of early 2020, so the HEIF file option should not be considered a general, everyday alternative to JPEGs. But there’s a clear trend in the electronics world toward increasing adaptation of HDR-compatible displays. HEIF files from the EOS-1D X Mark III can be viewed and edited in versions of Canon’s Digital Photo Professional (DPP) software that are compatible with files from the EOS-1D X Mark III camera.
It also adds:
Canon expects future updates to select high-end Canon printers, making them compatible with the expanded tonal range of HEIF files, via “HDR Print”.