A few smartphones and tablets have launched with support for HDR video, but the Google Pixel and Pixel XL were not among them. Google enabled HDR playback in YouTube recently and apparently didn't like that its own phones were going to be left out of the fun. We were surprised to see the Pixels show up on the supported list, so we asked Google what was going on. It turns out the Pixels are doing YouTube HDR in software.
Usually, OEMs have to work closely with SoC vendors to make sure a phone's hardware can decode HDR video bitstreams. Phones like the Galaxy S8, LG G6, and LG V30 all have built-in support for HDR video, not that there's a ton of content yet. The Pixel and Pixel XL don't have hardware support, so Google created a custom software decoder and rendering stack to make it possible. Here's what Google told us when we asked.
We're using a highly optimized software decoder and custom rendering stack, and were able to extend support to Pixel devices. Next generation mobile devices with hardware acceleration will perform even better.
So, the Pixel and Pixel XL can do HDR video on YouTube, but that doesn't extend to other platforms. The tidbit about "next generation mobile devices" is interesting. Google might be saying that future Pixels will have hardware HDR support.