From PS3 Developer wiki
Jump to: navigation, search


The images inside .rco files are indexed in the embedded RCOXML code of the .rco container under the XML element ImageTree. See Resource Container (RCO) and RCOXML Coding

All the images inside RCO files (with a few exceptions) uses a sony image format named GIM. See Graphic Image Map (GIM) and GimConv


The values marked in red are optional, the presence of the unknown specific for PS3 can be deduced based on the "rco version" in the rco header, only exists in PS3 RCO's (PSP doesnt uses it). See rcomage talk page. The presence of the other optional value file_uncompressed_size can be deduced by reading the entry itself

The file_compression feature adds a compression layer over the file format (pointless for image formats that are nativelly compressed like GIM or JPG)

Offset Length Name Example Notes
0x00 0x02 file_format 0x0=PNG
0x02 0x02 file_compression 0x0=NONE
0x04 0x04 file_size either compressed or uncompressed, this is the final size of the file stored inside the rco
0x08 0x04 file_offset
0x0C 0x04 unknown Most PS3 RCOs have this extra value - probably something to do with planes/frames?? usually 0x1
0x10 0x04 file_uncompressed_size Optional. Doesn't exist if file_compression = NONE, for PSP is located 4 bytes before because the previous value doesn't exists
  • unknown
    • RCO files version 0x93 included in some PS3 pre-retail firmwares (such DECR 082.006) doesnt have this value. But rcomage expects it to be there and when trying to extract the RCo contents it returns an error, loses the TOC track, and then does a "jump" of 4 bytes to locate the TOC track again and continue reading, The problem doesnt seems to be critical, the extraction is fine (the rebuilding not). This is an example of the error on system_plugin_bg.rco DECR 082.006
Warning: [entry (0xf4)] Unexpected value 0x20a4 for PS3 image - expected 0x1.
Warning: [entry (0xcc)] Entry boundaries not aligned (going forward -4 bytes)