The banding is SUPER monitor dependent, its noticeable on my 4k monitor, super apparent on a different monitor with a terrible LCD panel, and not at all visible on my iPad.
I wonder if the author took that into consideration.
I wonder if the author took that into consideration.
As a video codec developer I was a little sad about that, actually. I had to start looking closer to see problems.
That is indeed surprising. Is it iPad or iPad Pro? It is technically possible that your monitors only support 8bpp color depth while your iPad Pro supports 10bpp (via the P3 color space) and the WebP file has a smooth gradient only when viewed with 10bpp or more. But I can't really believe that, as the original JPEG file still looks like 8bpp and doesn't have any further color profile attached.
It could simply be an effect of brightness -- do you have your 4K monitor set to bright, while your iPad is much dimmer? (Remember Apple devices have adaptive brightness enabled by default as well.)