MR image - Revision history

Darc: Reverted edits by Darc (talk) to last revision by Unknown user

2023-10-11T00:23:30Z

Reverted edits by Darc (talk) to last revision by Unknown user

← Older revision		Revision as of 00:23, 11 October 2023
Line 72:		Line 72:
	# input: Byte array		# input: Byte array
	# output: Byte array		# output: Byte array
	# ~~size~~: Size of input in bytes (image width * image height)		# input_size: Size of input in bytes (image width * image height)
	# returns: Size of the compressed data		# returns: Size of the compressed data
	def mr_encode(input, output, ~~size~~):		def mr_encode(input, output, input_size):
			run = 0
	length = 0		length = 0
	position = 0		position = 0
	~~run = 0~~
			while(position < input_size):
	while(position < ~~size~~):
	run = 1		run = 1

	while((run < 0x17f) and (position+run < ~~size~~) and (input[position] == input[position+run])):		while((run < 0x17f) and (position+run < input_size) and (input[position] == input[position+run])):
	run += 1		run += 1

Line 112:		Line 112:
	return length		return length
	</syntaxhighlight>		</syntaxhighlight>

	==Decoding Algorithm==		==Decoding Algorithm==
	<syntaxhighlight lang="c" line="line">		<syntaxhighlight lang="c" line="line">
	# input: Byte array		# input: Byte array
	# ~~cdata_size~~: Size of input in bytes		# input_size: Size of input in bytes
	# ~~idata_size~~: Size of uncompressed data in bytes (image width * image height)		# uncompressed_size: Size of uncompressed data in bytes (image width * image height)
	# returns: Decoded image data		# returns: Decoded image data
	def mr_decode(input, ~~cdata_size~~, ~~idata_size~~):		def mr_decode(input, input_size, uncompressed_size):
			run = 0
	position = 0		position = 0
	idx_position = 0		idx_position = 0
	~~run = 0~~		indexed_data = array("B", "\x00" * uncompressed_size)
	indexed_data = array("B", "\x00" * ~~idata_size~~)

	while(position < ~~cdata_size~~):		while(position < input_size):
	first_byte = input[position]		first_byte = input[position]
	if((position+1) < ~~cdata_size~~):		if((position+1) < input_size):
	second_byte = input[position+1]		second_byte = input[position+1]

Line 152:		Line 151:
	# Writing decompressed bytes		# Writing decompressed bytes
	for i in range(run):		for i in range(run):
	~~# The additional byte (+ 1) is useless, but it always present in MR files.~~		if(idx_position+i < uncompressed_size):
	if(idx_position+i < ~~idata_size~~):
	indexed_data[idx_position+i] = first_byte		indexed_data[idx_position+i] = first_byte

Darc: /* Encoding Algorithm */

2023-10-11T00:19:53Z

Encoding Algorithm

← Older revision		Revision as of 00:19, 11 October 2023
Line 72:		Line 72:
	# input: Byte array		# input: Byte array
	# output: Byte array		# output: Byte array
	# ~~input_size~~: Size of input in bytes (image width * image height)		# size: Size of input in bytes (image width * image height)
	# returns: Size of the compressed data		# returns: Size of the compressed data
	def mr_encode(input, output, size):		def mr_encode(input, output, size):

Darc: /* Decoding Algorithm */

2023-10-11T00:18:47Z

Decoding Algorithm

← Older revision		Revision as of 00:18, 11 October 2023
Line 116:		Line 116:
	<syntaxhighlight lang="c" line="line">		<syntaxhighlight lang="c" line="line">
	# input: Byte array		# input: Byte array
	# ~~input_size~~: Size of input in bytes		# cdata_size: Size of input in bytes
	# ~~uncompressed_size~~: Size of uncompressed data in bytes (image width * image height)		# idata_size: Size of uncompressed data in bytes (image width * image height)
	# returns: Decoded image data		# returns: Decoded image data
	def mr_decode(input, ~~input_size~~, ~~uncompressed_size~~):		def mr_decode(input, cdata_size, idata_size):
	~~run = 0~~
	position = 0		position = 0
	idx_position = 0		idx_position = 0
	indexed_data = array("B", "\x00" * ~~uncompressed_size~~)		run = 0
			indexed_data = array("B", "\x00" * idata_size)

	while(position < ~~input_size~~):		while(position < cdata_size):
	first_byte = input[position]		first_byte = input[position]
	if((position+1) < ~~input_size~~):		if((position+1) < cdata_size):
	second_byte = input[position+1]		second_byte = input[position+1]

Line 152:		Line 152:
	# Writing decompressed bytes		# Writing decompressed bytes
	for i in range(run):		for i in range(run):
	if(idx_position+i < ~~uncompressed_size~~):		# The additional byte (+ 1) is useless, but it always present in MR files.
			if(idx_position+i < idata_size):
	indexed_data[idx_position+i] = first_byte		indexed_data[idx_position+i] = first_byte

Darc: /* Encoding Algorithm */

2023-10-11T00:16:38Z

Encoding Algorithm

← Older revision		Revision as of 00:16, 11 October 2023
Line 74:		Line 74:
	# input_size: Size of input in bytes (image width * image height)		# input_size: Size of input in bytes (image width * image height)
	# returns: Size of the compressed data		# returns: Size of the compressed data
	def mr_encode(input, output, ~~input_size~~):		def mr_encode(input, output, size):
	~~run = 0~~
	length = 0		length = 0
	position = 0		position = 0
			run = 0
	while(position < ~~input_size~~):
			while(position < size):
	run = 1		run = 1

	while((run < 0x17f) and (position+run < ~~input_size~~) and (input[position] == input[position+run])):		while((run < 0x17f) and (position+run < size) and (input[position] == input[position+run])):
	run += 1		run += 1

Line 112:		Line 112:
	return length		return length
	</syntaxhighlight>		</syntaxhighlight>

	==Decoding Algorithm==		==Decoding Algorithm==
	<syntaxhighlight lang="c" line="line">		<syntaxhighlight lang="c" line="line">

Unknown user: /* Header */

2020-10-14T04:56:04Z

Header

← Older revision		Revision as of 04:56, 14 October 2020
Line 25:		Line 25:

	A MR file starts off with a 30 byte header.		A MR file starts off with a 30 byte header.
	===Header===		===File Header===
	{\| class="wikitable" style="text-align: center"		{\| class="wikitable" style="text-align: center"
	\|-		\|-

Unknown user: /* Header */

2020-10-14T04:54:14Z

Header

← Older revision		Revision as of 04:54, 14 October 2020
Line 26:		Line 26:
	A MR file starts off with a 30 byte header.		A MR file starts off with a 30 byte header.
	===Header===		===Header===
	{\| class="wikitable"		{\| class="wikitable" style="text-align: center"
	\|-		\|-
	! Size (bytes) !! Contents		! Size (bytes) !! Contents
	\|-		\|-
	\| 2 \|\| "MR"		\| 2
			\|style="text-align: left;"\| "MR"
	\|-		\|-
	\| 4 \|\| Total file size		\| 4
			\|style="text-align: left;"\| Total file size
	\|-		\|-
	\| 4 \|\| Crap (fill with 0's)		\| 4
			\|style="text-align: left;"\| Crap (fill with 0's)
	\|-		\|-
	\| 4 \|\| Image data offset in bytes (Header size + Palette size)		\| 4
			\|style="text-align: left;"\| Image data offset in bytes (Header size + Palette size)
	\|-		\|-
	\| 4 \|\| Image width		\| 4
			\|style="text-align: left;"\| Image width
	\|-		\|-
	\| 4 \|\| Image height		\| 4
			\|style="text-align: left;"\| Image height
	\|-		\|-
	\| 4 \|\| Crap (fill with 0's)		\| 4
			\|style="text-align: left;"\| Crap (fill with 0's)
	\|-		\|-
	\| 4 \|\| Amount of colors in palette		\| 4
			\|style="text-align: left;"\| Amount of colors in palette
	\|}		\|}

Unknown user: /* Header */

2020-10-14T04:52:27Z

Header

← Older revision		Revision as of 04:52, 14 October 2020
Line 28:		Line 28:
	{\| class="wikitable"		{\| class="wikitable"
	\|-		\|-
	! Size !! Contents		! Size (bytes) !! Contents
	\|-		\|-
	\| 2 ~~bytes~~ \|\| "MR"		\| 2 \|\| "MR"
	\|-		\|-
	\| 4 ~~bytes~~ \|\| Total file size		\| 4 \|\| Total file size
	\|-		\|-
	\| 4 ~~bytes~~ \|\| Crap (fill with 0's)		\| 4 \|\| Crap (fill with 0's)
	\|-		\|-
	\| 4 ~~bytes~~ \|\| Image data offset in bytes (Header size + Palette size)		\| 4 \|\| Image data offset in bytes (Header size + Palette size)
	\|-		\|-
	\| 4 ~~bytes~~ \|\| Image width		\| 4 \|\| Image width
	\|-		\|-
	\| 4 ~~bytes~~ \|\| Image height		\| 4 \|\| Image height
	\|-		\|-
	\| 4 ~~bytes~~ \|\| Crap (fill with 0's)		\| 4 \|\| Crap (fill with 0's)
	\|-		\|-
	\| 4 ~~bytes~~ \|\| Amount of colors in palette		\| 4 \|\| Amount of colors in palette
	\|}		\|}

	===Palette===		===Palette===
	The header is followed by the image's palette. The palette is composed of palette entries where each palette entry is 4 bytes long and is stored as BGRA. The alpha byte goes unused. The maximum number of palette entries is '''128'''.		The header is followed by the image's palette. The palette is composed of palette entries where each palette entry is 4 bytes long and is stored as BGRA. The alpha byte goes unused. The maximum number of palette entries is '''128'''.

Unknown user at 17:52, 30 May 2020

2020-05-30T17:52:47Z

← Older revision		Revision as of 17:52, 30 May 2020
Line 60:		Line 60:

	==Encoding Algorithm==		==Encoding Algorithm==
	<~~pre~~>		<syntaxhighlight lang="c" line="line">
	# input: Byte array		# input: Byte array
	# output: Byte array		# output: Byte array
Line 102:		Line 102:

	return length		return length
	</~~pre~~>		</syntaxhighlight>
	==Decoding Algorithm==		==Decoding Algorithm==
	<~~pre~~>		<syntaxhighlight lang="c" line="line">
	# input: Byte array		# input: Byte array
	# input_size: Size of input in bytes		# input_size: Size of input in bytes
Line 148:		Line 148:

	return indexed_data		return indexed_data
	</~~pre~~>		</syntaxhighlight>

Unknown user: Added algorithms and finishing touches to about section

2020-01-15T05:18:59Z

Added algorithms and finishing touches to about section

@@ Line 1: / Line 1: @@
 ==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. [[File:Windows CE boot screen.png|thumb|Games powered by Windows CE boot screen]]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.
+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. [[File:Windows CE boot screen.png|thumb|Games powered by Windows CE boot screen]]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. The MR image must be inserted into a [[IP.BIN]] file at offset '''0x3820''' in order to be viewed during boot sequence. Since [[IP.BIN]] is restricted to a 32k file size, there are a couple of guidelines the MR image must meet to in order to fit inside the [[IP.BIN]].
 <br/>
 '''MR Image must be:'''
@@ Line 47: / Line 47: @@
 |}
 ===Palette===
-The header is followed by the image's palette.  The palette is composed of palette entries where each palette entry is 4 bytes long and is stored as BGRA. The alpha byte goes unused.
+The header is followed by the image's palette.  The palette is composed of palette entries where each palette entry is 4 bytes long and is stored as BGRA. The alpha byte goes unused.  The maximum number of palette entries is '''128'''.
 {| class="wikitable"
 |-
@@ Line 57: / Line 57: @@
 In total, the byte size of your palette should be number of colors * 4.
 ===Image Data===
-Lastly, the image data.  The image data is compressed using a form of Run-Length Encoding (RLE). The pseudocode algorithms to encode/decode the image data are shown below.
+Lastly, the image data. The image data is basically an array of indices, each a byte long, that refers to a palette entry in the palette. The image data is compressed using a form of Run-Length Encoding (RLE). The python algorithms to encode/decode the image data are shown below.
-'''Encoding Algorithm'''
+==Encoding Algorithm==
-'''Decoding Algorithm'''
+        while((run < 0x17f) and (position+run < input_size) and (input[position] == input[position+run])):

Unknown user at 08:34, 11 January 2020

2020-01-11T08:34:12Z

← Older revision		Revision as of 08:34, 11 January 2020
Line 59:		Line 59:
	Lastly, the image data. The image data is compressed using a form of Run-Length Encoding (RLE). The pseudocode algorithms to encode/decode the image data are shown below.		Lastly, the image data. The image data is compressed using a form of Run-Length Encoding (RLE). The pseudocode algorithms to encode/decode the image data are shown below.

	==Encoding Algorithm==		'''Encoding Algorithm'''

	==Decoding Algorithm==		'''Decoding Algorithm'''