Graphic Image Map (GIM)

Description

Graphic Image Map ? (GIM) is an image format, allows for tenths of different storage settings and by combining settings results in hundreds (or thousands) of different GIM files that are structurally different, to simplify concepts people is naming this different GIM files as "GIM formats" but strictly speaking the GIM format is always the same, the amount of GIM formats used in PlayStation consoles is limited though (restricted by the graphic enviroment, libraries, etc...). GIM files was found used in PSP and PS3 firmwares inside Resource Container (RCO) files, PlayStation 3 Theme (P3T) files, etc... See GimConv and Multimedia Formats and Tools#GIM

The acronym of GIM used in this wiki (Graphic Image Map) is an speculative unnofficial name based in how the data is stored in the internal GIM structure, if someone finds the official codename somewhere please report back and we will change it

Structure

• Overview (4 unknown values left, marked in red color)

Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00000000  2E 47 49 4D 31 2E 30 30 00 50 53 50 00 00 00 00  .GIM1.00.PSP....     <- GIM header
00000010  00 02 00 00 00 00 00 EC 00 00 00 10 00 00 00 10  .......ì........     <- Block 0x02 header (Root)
00000020  00 03 00 00 00 00 00 80 00 00 00 10 00 00 00 10  .......€........        <- Block 0x03 header (Picture)
00000030  00 04 00 00 00 00 00 70 00 00 00 70 00 00 00 10  .......p...p....           <- Block 0x04 header (Image)
00000040  00 30 00 00 00 03 00 00 00 04 00 02 00 20 00 10  .0........... ..              <- Block 0x04 Data
00000050  00 01 00 02 00 00 00 00 00 00 00 30 00 00 00 40  ...........0...@              <- Block 0x04 Data
00000060  00 00 00 60 00 00 00 00 00 01 00 01 00 03 00 01  ...`............              <- Block 0x04 Data
00000070  00 00 00 40 00 00 00 00 00 00 00 00 00 00 00 00  ...@............              <- Block 0x04 Index
00000080  CA 5E 11 00 CA 5E 12 00 CA 5E 13 00 CA 5E 14 00  Ê^..Ê^..Ê^..Ê^..                 <- Block 0x04 Frame
00000090  CA 5E 21 00 CA 5E 22 00 CA 5E 23 00 CA 5E 24 00  Ê^!.Ê^".Ê^#.Ê^$.                 <- Block 0x04 Frame
000000A0  00 FF 00 00 00 00 00 5C 00 00 00 5C 00 00 00 10  .ÿ.....\...\....        <- Block 0xFF header (Fileinfo)
000000B0  34 78 32 5F 43 41 35 45 78 79 5F 33 32 62 69 74  4x2_CA5Exy_32bit           <- Block 0xFF Strings
000000C0  73 2E 62 6D 70 00 41 64 6D 69 6E 69 73 74 72 61  s.bmp.Administra           <- Block 0xFF Strings
000000D0  74 6F 72 00 53 75 6E 20 41 70 72 20 31 35 20 30  tor.Sun Apr 15 0           <- Block 0xFF Strings
000000E0  31 3A 32 35 3A 30 32 20 32 30 31 38 00 47 69 6D  1:25:02 2018.Gim           <- Block 0xFF Strings
000000F0  43 6F 6E 76 20 31 2E 32 30 68 00 00              Conv 1.20h..               <- Block 0xFF Strings

GIM header

Offset	Length	Example	Name	Description	Notes
0x00	0x04	.GIM	signature	little = MIG. big = .GIM	This is the first place affected by format_endian in GimConv.cfg
0x04	0x04	1.00	version		Always 1.00 ?
0x08	0x04	PSP	format_style	std = nothing ps3 = nothing psp = PSP	Configured by format_style in GimConv.cfg
0x0C	0x04	00 00 00 00	padding/unused ?	Unknown	Always 0 ?

Block headers (generic)

Offset	Length	Example	Name	Description	Notes
0x00	0x02	00 02	block_id	0x02 = Root (first level) 0x03 = Picture (second level) 0x04 = Image (third level) 0x05 = Palette (third level) 0xFF = Fileinfo (second level)	Block identifyer
0x02	0x02	00 00	block_unk	0x00 = ? 0x10 = ?	Unknown
0x04	0x04	00 00 00 EC	block_size	Size of this block + children blocks
0x08	0x04	00 00 00 10	block_header_next	Next block relative offset
0x0C	0x04	00 00 00 10	block_data_offset	Block data relative offset

Block data (by block ID)

0x02 (Root)

Is the parent of block 0x03 (Picture) and 0x0FF (Fileinfo)

0x03 (Picture)

Is the parent of block 0x04 (Image) and block 0x05 (Palette)

• Experimental notes
  • This block is repeated when using the option merge_mode = picture

0x04 (Image)

The image block contains some info about the image, and the pixel color info at bottom stored as levels or frames

• Experimental notes
  • This block is repeated when using the option merge_mode = image

Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00000040  00 30 00 00 00 03 00 00 00 04 00 02 00 20 00 10  .0........... ..
00000050  00 01 00 02 00 00 00 00 00 00 00 30 00 00 00 40  ...........0...@
00000060  00 00 00 60 00 00 00 00 00 01 00 01 00 03 00 01  ...`............

Offset	Length	Example	Name	Description	Notes
0x00	0x02	00 30	block_data_lenght	Size of the block data	Indicates the relative offset of the area located inmediatly after frame_count
0x02	0x02	00 00	b45_unk1	?	Ignored ?
0x04	0x02	00 03	image_format	0x00 = rgba5650 (16 bit no alpha) 0x01 = rgba5551 (16 bit sharp alpha) 0x02 = rgba4444 (16 bit gradient alpha) 0x03 = rgba8888 (32 bit gradient alpha) 0x04 = index4 (16 colors) 0x05 = index8 (256 colors) 0x06 = index16 (16 colors with alpha ?) 0x07 = index32 (256 colors with alpha ?) 0x08 = dxt1 (no alpha) 0x09 = dxt3 (sharp alpha) 0x0A = dxt5 (gradient alpha) 0x108 = dxt1ext 0x109 = dxt3ext 0x10A = dxt5ext	Configured by image_format in GimConv.cfg Format in the GIS
0x06	0x02	00 00	pixel_order	0x00 = normal 0x01 = faster	Configured by pixel_order in GimConv.cfg with values: normal (default) or faster Order in the GIS with values: NORMAL or PSPIMAGE
0x08	0x02	00 04	width	Image/palette width in pixels	Restricted by limit_image_width in GimConv.cfg Width in the GIS
0x0A	0x02	00 02	height	Image/palette height in pixels	Restricted by limit_image_height in GimConv.cfg Height in the GIS
0x0C	0x02	00 20	bpp_align	Image/palette bits per pixel alignment
0x0E	0x02	00 10	pitch_align	Image/palette X alignment	PitchAlign in the GIS
0x10	0x02	00 01	height_align	Image/palette Y alignment	HeightAlign in the GIS
0x12	0x02	00 02	b45_unk2	?	Ignored ?
0x14	0x04	00 00 00 00	b45_unk3	?	Ignored ?
0x18	0x04	00 00 00 30	index_start	Index relative start offset
0x1C	0x04	00 00 00 40	pixels_start	First plane/level/frame relative start offset
0x20	0x04	00 00 00 60	pixels_end	Last plane/level/frame relative end offset
0x24	0x04	00 00 00 00	plane_mask	Indicates a color (for alpha mask ?)	PlaneMask in the GIS
0x28	0x02	00 01	level_type	0x00 = Illegal 0x01 = MIPMAP 0x02 = MIPMAP2 (used for palettes)	LevelType in the GIS
0x2A	0x02	00 01	level_count	Number of mipmaps	Restricted by limit_level_count in GimConv.cfg (default max 8) LevelCount in the GIS
0x2C	0x02	00 03	frame_type	0x00 = Illegal ? 0x01 = Illegal ? 0x02 = Illegal ? 0x03 = SEQUENCE	FrameType in the GIS
0x2E	0x02	00 01	frame_count	Number of frames	Restricted by limit_frame_count in GimConv.cfg (default no limit) FrameCount in the GIS
0x30	any	N/A	user_data	Optional User Data area	Enabled by update_userdata = on in GimConv.cfg. Stores the contents of <filename>.dat
varies	varies	N/A	padding	Optional padding	To align user_data to 4 bytes

Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00000070  00 00 00 40 00 00 00 00 00 00 00 00 00 00 00 00  ...@............

IMAGE_INDEX (contains IMAGE_PLANE/IMAGE_LEVEL/IMAGE_FRAME) ?
PALETTE_INDEX (contains PALETTE_LEVEL/PALETTE_FRAME) ?

Offset	Length	Example	Name	Description	Notes
0x30	0x04	00 00 00 40	frame_n_offset	Where <n> is the frame number	This entry is repeated one time for every level_count or frame_count
0x34	0x0C	00 00 00 ...	padding	Optional padding	To align the block to 16 bytes

After this index comes the planes/levels/frames (the bytes with pixels color info), are one or several images concatenated, for experimental purposes can be added manually by using GimConv.cfg setting merge_mode with values frame and level, and probably plane too

Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00000080  CA 5E 11 00 CA 5E 12 00 CA 5E 13 00 CA 5E 14 00  Ê^..Ê^..Ê^..Ê^..
00000090  CA 5E 21 00 CA 5E 22 00 CA 5E 23 00 CA 5E 24 00  Ê^!.Ê^".Ê^#.Ê^$.

IMAGE_INDEX
IMAGE_PLANE
IMAGE_LEVEL
IMAGE_FRAME

PALETTE_INDEX
PALETTE_LEVEL
PALETTE_FRAME

0x05 (Palette)

The palette block is used for indexed color formats (index4 index8 index16 index32), to create a GIM with a palette is needed to use as input an image that already contains a color palette (such BMP or DDS)

The concept of "palette" is a bit confusing because here is used for two different things, the block 0x05 is codenamed palette as a general concept, the file structure is the same than the block 0x04 (image), both ends with the user_data (optional), then it comes an index to indicate how many palettes there are and its offsets (usually only one palette), and then starts an area where are stored the pixel colors... this area to store pixel colors is the real palette in design slang but to avoid this name confussion we can call it the colormap

• The differences in between block 0x04 (image) and block 0x05 (palette) are minor, only differs in how are used
  • The palette (block 0x05) is located before the image (block 0x04) in the block hierarchy of the GIM structure, doesnt seems to be anything that connects them, other than the fact that "the palette goes first"
  • The palette stores the "colormap", and the image stores an "indexmap" (and every index value in the image loads a color from the palette colormap)
  • The palette only allows for palette_format = rgba8888 rgba4444 rgba5551 rgba5650
  • The "colormap" is stored as an image of 256x1 pixels (image_width = 0x100 image_height = 0x1) and allows to store 256 colors
  • The "colormap" has a reserved bytes size in the GIM file structure based on the palette format, 0x400 bytes in rgba8888, 0x200 in rgba4444, etc...), if the number of colors is smaller than 256 the "colormap" area will have some bytes filled with zeroes (not used)
  • The palette is stored as level_type = MIPMAP2

0xFF (Fileinfo)

This block only exists if the GIM is build using the setting update_fileinfo = on. Initially in old PS3 firmwares all the GIM files was made this way, eventually sony stopped using this setting and GIM files was updated/replaced by new ones without this fileinfo block. But there are many GIM files inside latest PS3 firmware that contains this fileinfo block (are GIM files made years ago and never was updated, this can be seen in the timestamps stored in them around 2005/2006)

Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

000000B0  34 78 32 5F 43 41 35 45 78 79 5F 33 32 62 69 74  4x2_CA5Exy_32bit
000000C0  73 2E 62 6D 70 00 41 64 6D 69 6E 69 73 74 72 61  s.bmp.Administra
000000D0  74 6F 72 00 53 75 6E 20 41 70 72 20 31 35 20 30  tor.Sun Apr 15 0
000000E0  31 3A 32 35 3A 30 32 20 32 30 31 38 00 47 69 6D  1:25:02 2018.Gim
000000F0  43 6F 6E 76 20 31 2E 32 30 68 00 00              Conv 1.20h..

Offset	Length	Example	Name	Description	Notes
0x00	0x16	4x2_CA5Exy_32bits.bmp	project_name	Original file name and file extension	ProjectName in the GIS
0x16	0x0E	Administrator	user_name	Microsoft windows user account	UserName in the GIS
0x24	0x19	Sun Apr 15 01:25:02 2018	saved_date	Timestamp	SavedDate in the GIS
0x3D	0x0E	GimConv 1.20h	originator	GimConv version	Originator in the GIS
0x4B	0x01	00	padding	Optional padding	To align fileinfo block to 4 bytes

Links

• http://www.pujia8.com/articles/34/
• https://tieba.baidu.com/p/1733245285