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Old 20 October 2016, 13:53   #33
Thorham
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Join Date: Sep 2007
Location: Rotterdam/Netherlands
Age: 41
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Quote:
Originally Posted by thellier View Post
So the total is 64+64 values values possibles for each R, G or B channels
Not exactly.

A HAM pixel can do any of the four following things:

1. Be set to a palette color.
2. Take on the color of the pixel to the left, and set the red component.
3. Take on the color of the pixel to the left, and set the green component.
4. Take on the color of the pixel to the left, and set the blue component.

For the first pixel type this means 4 bits per channel in HAM6, and 8 bits per channel in HAM8.

For pixel types 2, 3 and 4 you can set 4 bits of the changing component in HAM6, and 6 bits in HAM6.

Since most pixels in a HAM image are usually of types 2, 3 and 4, most of the pixels are usually 6 bits per channel in HAM8. A big factor here is the fact that there are only 64 palette colors in HAM8, making it hard to use the extra bits you can get from the palette, hence the number 262144 being the most relevant.

When you start using palette slicing in HAM8 and use the right conversion algorithm, it may be possible to make better use of the palette color's 8 bit channels.

So basically HAM8 pixels can have 8 bit components, but they usually become 6 bits rather quickly.
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