The HDR+ siggraph paper (hdrplusdata.org) states that they use Halide, as does the newer siggraph paper on the Pixel's portrait mode (http://graphics.stanford.e

The HDR+ siggraph paper (hdrplusdata.org) states that they use Halide, as does the newer siggraph paper on the Pixel's portrait mode (http://graphics.stanford.edu/papers/portrait/wadhwa-portrait-sig18.pdf http://graphics.stanford.edu/papers/portrait/wadhwa-portrait...), and the paper on the Pixel's video denoising algorithm (http://www.chiakailiang.org/papers/ehmann_2018_rtv.pdf http://www.chiakailiang.org/papers/ehmann_2018_rtv.pdf). The Pixel camera is riddled with Halide code, but of course it's all closed-source. I can also vouch for the youtube use, having been tangentially involved in it and given permission to state that they use it.