10 Bit
-----
1bit = mode Bit
     0= Setting of high and low bits at the same time
     1= Setting of low bits 
3bits Red
3bits Green
3bits Blue

This HAM format allows setting of 512 direct colors in 1 pixel.
And with the next pixel refine it to one of 260000 colors.

The advantage of this mode is that is does not color bleed.
You never have any really "wrong colors" as you can with HAM.

This mode could also be implemented with 13bits then it would work as direct color mode allowing the full ragne of 16,000,000 colors.

What do you think about this?

Would anyone help to research this and offer writing a tool to convert 24bit images to these modes and back for testing?
Then we could together verify how these modes look and if there is a visual difference to full truecolor.

Of course, it is lossy, but GREAT for just games and quickie presentations (I think we could EASILY kick "powerpoint" to the CURB!!!!) but not for keepsake photos, serious DTP or the like.

Could animations be run like this? 32 bits could store 3 separate frames to display!!!!!

We could get real time video playback, and no decompressing necessary!

NATAMI RULES!!!!!!!!

Instead of loading the LSB only, a better approach would be to add a delta value to the RGB sample value, that is:

control bit = 0  -->  load value into MSB and LSB
control bit = 1  -->  add value to pixel value to the left.

Smooth color ramps are then easily implemented. Basically, the display logic would implement a DPCM decoder (differential pulse coded modulation).

Needless to say, this works better in YCbCr space than in RGB space. With 12bpp, components could be addressed individually.

On the other hand, who would probably code images this way if a true color mode is available? Drawing/rendering etc. is very hard, and if the bandwidth is available, I don't see the need for such tricks anymore. HAM goes back to times where bandwidth was a premium.

Greetings,

Thomas

Bandwidth IS at a premium...

We have only a 150 MHz CPU and co-processors at our disposal. We need every little voodoo trickery that we can put our fingers on to get the high resolutions to work for us, maybe even stretching out to 1920*1080!!!! We still need it even if 1920*1080 still isn't possible.

On the other hand, on HAM screens (or DPCM screens), it is very hard to do any animation, interactivity, drawing, displaying windows etc. without distorting the visual appearance. IOW, they are only useful for painting/drawing and showing static pictures, all tasks that do not require lots of bandwidth by the blitter or the CPU anyhow.

Thus, what would be the use case for such a format? For HAM, it is backwards compatibility. For the new format, I simply cannot imagine a good application. Animation/gaming is *not* an application as you need to put a lot of complexity into avoiding artifacts. Showing pictures is not an application because that is easier done with truecolor in first place.

So long,
Thomas

Would it be possible to have some kind of ham mode back playfied with a non HAM front playfield?

  10 Bit
  -----
  1bit = mode Bit
      0= Setting of high and low bits at the same time
      1= Setting of low bits 
  3bits Red
  3bits Green
  3bits Blue
  

high bit=1, 7 low bits sets Y
high bit=0, bit 6=0 - set Cb
high bit=0, bit 6=1 - set Cr

The increased bandwidth and the integration of true color mode does not necessarily rule out the improvement of original features. HAM mode aficionados may appreciate. Personally, I'd be interested in examples of pictures.

Thank

In the end, the total system bandwidth will be 6.4GB/s.

Fine.

Vertical scroll like 1942 and other games like that do not have the HAM artifact problem.

But i think it has been said before moving images in HAM format are very hard to correctly.