Originally Posted by Mike Garrett
The problem with streaming is, 4K HDR at 60P requires more than the 13.5Gbps HDMI that the 285 can't do, so you get banding.
13.5 gbps is enough to deliver 4K60 in HDR10 in 4:2:0, though.
I read that the real problem with last years' Sonys is that their internal processing can't handle 10-bit at 60hz.
4:2:0 instead of 4:2:2 won't introduce significant banding on its own, if at all, especially since chroma upscaling done quite well these days and smooths out any kinks. Banding isn't really limited by spatial resolution, but by bit depth, and HDR10 in 4:2:0 is just fine. I mean, that's literally what UHD Blurays are encoded in, and virtually every other source, so why wouldn't it be perfectly acceptable? Why would 4:2:0 be OK vis-a-vis HDR banding at 24 fps but not 60 fps? That does not compute.
Sony cheaped out on their processor too much, and had they not done so, 13.5 gbps would have been just fine for gaming streaming sources at 60hz in HDR10 without banding. Thankfully they fixed that this year. Streaming is too important these days, and it's often set to 60hz. Even if you don't play games you likely still want banding-free HDR at 60hz. So I wouldn't recommend the 285 at all unless it's 100% dedicated to 24 fps upstream electronics and content, only. Which might be fine for some. If someone gave me a Sony 285 for free, I'd sell it and buy the 295, or buy something cheaper and keep the money (most likely).
HDMI bandwidth being 13.5 gbps is not the cause of banding in the 285. That's what Billy Lynn is encoded to (4:2:0 4K60 HDR10), and I 100% doubt that any other streaming services are actually delivering 4:2:2 which is what 18 gbps HDMI maxes out at. The only real source of 4:2:2 native is games, and even there, it doesn't matter. I'm not even sure that 4:2:2 is much better than 4:2:0, because 4:2:0 is evenly compressed in X and Y dimensions, whereas 4:2:2 is only compressed by 50% in Y. So you get better horizontal resolution than vertical. The only argument in favour of 4:2:2 I think is that upscaling to 4:4:4 is simpler. But aside from games, there is no content that's streamed in 4:2:2 as far as I'm aware.
All video is shipped to consumers in 4:2:0 and 13.5 gbps is just fine for that, even at 60hz and in HDR10. I'd even argue that it doesn't matter for games either, because the main factor limiting games from looking real isn't really their resolution, it's the quality of their pixels and how they are produced. Games are still a ways off before they can compete with a UHD Bluray like Billy Lynn, in terms of realism.
In short, chroma doesn't matter. Except for PC text, but even HDMI 2.0b's 18 gbps isn't sufficient for HDR10 there, as you need 4:4:4 for 1:1 text and graphics. So even the 295 isn't good enough. We need HDMI 2.1, which is getting closer and closer! Hopefully next years' 4K projectors will have 4K 120hz in 4:4:4 HDR10+ and Dolby Vision too.