The big change with Android 8.1 DP2 is that the previously dormant Pixel Visual Core on Google’s 2017 flagship Pixel 2 smartphones is now enabled for developers. For those that need a refresher course, the Pixel Visual Core is Google's first custom-designed co-processor for consumer applications.
The chip features 8 custom, Google-designed cores that allow the Image Processing Unit (IPU) to perform 3 trillion operations per second. According to Google, it can process HDR+ content 5x faster than a general purpose SoC while using one-tenth the energy. You can take a look at the images below to see the difference that HDR+ can make for photographs taken in low-light conditions:
Photos taken on Pixel 2 w/ a third-party app. Picture on right is HDR+ on Pixel Visual Core (Source: Google)
"[HDR+] makes it possible to get excellent photos of scenes with a large range of brightness levels, from dimly lit landscapes to a very sunny sky," wrote Google's Ofer Shacham and Masumi Reynders back in October. "HDR+ produces beautiful images, and we’ve evolved the algorithm that powers it over the past year to use the Pixel 2’s application processor efficiently, and enable you to take multiple pictures in sequence by intelligently processing HDR+ in the background."
The Pixel Visual Core is included on both the Pixel 2 and Pixel 2 XL.
As for the public release of Android 8.1, Google expects that the final build will be available some time in December.