Re: Byte Addressability And Beyond

BGB wrote:

On 5/4/2024 1:44 AM, Lawrence D'Oliveiro wrote:

On Fri, 3 May 2024 22:11:44 -0500, BGB wrote:
 

Not a huge use-case in graphics, as noted, in most cases this is done
with 16 or 32 bit pixels; and bit-plane graphics are long since dead.

 What happens if we go beyond 32 bits? For example, hardware might

support

10 bits per pixel component.

A few typical formats:
   RGB555: 0rrrrrgg-gggbbbbb
   RGBA32: aaaaaaaa-rrrrrrrr-gggggggg-bbbbbbbb
   RGB30 : 00rrrrrr-rrrrgggg-ggggggbb-bbbbbbbb  (10-bit component RGB)

Though, for RGB30, there are variants with 10-bit linear RGB, and E5.F5 floating-point (sometimes used for HDR in OpenGL, as opposed to 4x Binary16).

None of these would really benefit from bit addressable memory though.

Nor are they serviced by any SIMD ISA.

Though, for LDR, going beyond 8-bit color depth doesn't gain much even if the monitor supports it natively. And had noted before when using a cheap LCD TV as a monitor, that it only seemed to be working at a roughly 6-bit color depth (like, it was seemingly slightly better than RGB555, but not by much).

Most people's eyes cannot even see the difference unless it is pointed
out to them.

Now I am using a 4K OLED, which does support 10b/component, but it doesn't make much difference in practice (and even if it did, most software wont make much use of it).

But, say, 5 to 8 bits per component is at least noticeable (better colors and less banding artifacts), 8 to 10 bits, not so much. Though, with the main exception being HDR (but then, over the 0.5 to 1.0 range, E5.F5 is only about as accurate as a 6-bit component).

Posterization is still a problem at 8-bits.