IOS 11 can help its users save on disk space. On the WWDC 2017, Apple announced that all devices equipped with iOS 11 support the HEIF and HEVC (H.265) codecs. So your photos and videos need significantly less space on the iPhone or iPad while maintaining the same high quality.
As reported among other things 9to5Mac , Apple assumes that the users with iOS 11 only half as much storage space for their pictures and videos need.
In recent years the videos recorded with the camera under iOS have been compressed with the H.264 standard and photos are output as JPEGs.
However, since Apple has improved its cameras year by year and the high-resolution content demand more storage space, the company has searched for new solutions and apparently found them with HEIF and HEVC.
Areas of application and advantages of the new codecs
Both of these codecs are not from Apple: HEVC (“High Efficiency Video Coding”), also known as H.265 or MPEG-H part 2, is a joint development of the Moving Picture Experts Group (MPEG) and the Video Coding Experts Group VCEG) and has existed for several years. It is used with 4K streaming services like Netflix & Amazon Video, but also with the Ultra HD Blu-ray.
HEIF (“High Efficiency Image File Format”) was finalized in 2015, halved file sizes compared to JPEG, and also had fewer artifacts. In addition, HEIF is much more versatile than other codecs. No wonder Apple would like to use the positive features of HEIF and HEVC for its iOS 11-equipped devices.