How's your banding?

I made short clips to test banding. They can be downloaded here (8 MB).

The frame consists of 32 vertical grey stripes that move slowly leftward. Each stripe differs from the next by one unit in 10-bit luma. I believe a proper display would show no visible edges or bands. It's not so in my display. How's yours?

There are two versions of the clip in the download. One is in ProRes HQ and the other is in uncompressed 10-bit. I'm sure the clips are equivalent pixel-by-pixel because I can peek into the uncompressed file and read its pixel values, and when the uncompressed is converted to ProRes and then back to uncompressed the pixel values are unchanged.

I first viewed the clips played in FCP7 and QT7.6. They more or less converted the 10-bit in the clips to 8-bit and displayed that. That should make 8 visible stripes from the clips' 32 invisible ones. But here and there are overly wide stripes and doubly visible steps. It was disconcerting, while making the test clip, to see some steps much more visible than others. I kept checking whether the clip was at fault. No, it's from the playback and display.

FCP7 and QT7.6 made the uncompressed clip look very different from the ProRes clip. The uncompressed clip displayed stripes with crisp edges. The ProRes clip looked much smoother. On closer examination, all its steps were hidden by single-pixel checkboarding: dither. Dithering covered the full width of one underlying 10-bit stripe. It looks like finger-jointed wood.

Who ordered the dither? The player must be deciding it, since no later element could distinguish the ProRes from the uncompressed 10-bit. I then played the clips with VLC player and with DaVinci Resolve. They made the two clips look alike. No dithering and also, no very large steps. Smarty-pants Apple software fails again.

True 10-bit playback and monitoring would make 32 stripes on the screen, probably with invisible boundaries. I'm not sure what the eye would make of that, since the right side of the picture is about 15% lighter than the left side.

I hope forum members can share how these clips display on their systems.
Can they be viewed on a broadcast monitor? How do they look?

Dennis Couzin
Berlin, Germany