MR image: Difference between revisions
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==File | ==File Format== | ||
===File Header=== | |||
A MR file starts with a 30 byte header. | |||
{| class="wikitable" | |||
|- | |||
! Size !! Contents | |||
|- | |||
| 2 bytes || "MR" | |||
|- | |||
| 4 bytes || Filesize | |||
|- | |||
| 4 bytes || Crap | |||
|- | |||
| 4 bytes || Image Data offset | |||
|- | |||
| 4 bytes || Image Width | |||
|- | |||
| 4 bytes || Image Height | |||
|- | |||
| 4 bytes || Crap | |||
|- | |||
| 4 bytes || Amount of colors in palette | |||
|} | |||
===Palette=== | |||
==Encoding== | ==Encoding== | ||
==Decoding== | ==Decoding== | ||
Revision as of 05:31, 11 January 2020
About
A MR image is an image format solely used inside an IP.BIN file to show off a logo during the boot screen process of the Sega Dreamcast.
This image format was used in commercialized Dreamcast games utilizing Windows CE SDK where we see a "Powered by Microsoft Windows CE" logo. It is now commonly used in homebrew to distinguish the creator(s) of the application or to disassociate the application being produced by or under license from Sega. Since IP.BIN is restricted to a 32k file size and the MR image must be inserted into that file in order to be displayed during the boot process, there are a couple of guidelines the MR image must meet to be shown during the boot process.
MR Image must be:
- 320x90 or less
- Max 128 colors
- Less than 8192 bytes to fit in a IP.BIN
- The transparent color is #c0c0c0, or 192, 192, 192 in RGB
File Format
File Header
A MR file starts with a 30 byte header.
| Size | Contents |
|---|---|
| 2 bytes | "MR" |
| 4 bytes | Filesize |
| 4 bytes | Crap |
| 4 bytes | Image Data offset |
| 4 bytes | Image Width |
| 4 bytes | Image Height |
| 4 bytes | Crap |
| 4 bytes | Amount of colors in palette |