Difference between revisions of "IMG archive"
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(various fixes, GTA IV section added) |
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| − | + | GTA's most commonly used [[archive file]]s are known by the extension <code>'''.img'''</code>. They have a very simple format and currently exist in multiple versions. | |
| − | + | == Structure == | |
| − | = | + | === Version 1 - GTA III & VC === |
| − | + | Version 1 archives, used in GTA III and Vice City, are actually split up into two files: the content directory (<code>.dir</code>) and the actual archive (<code>.img</code>). | |
| − | + | The directory is a list of files, each with name, offset and size of the file. The values for offset and size have to be ''multiplied by 2048'', since files are aligned to 2 KB boundaries. This means that even a file with only 123 byte content will take up 2 KB in the archive. Files are stored (usually) unsorted, uncompressed and linear (no directory tree). | |
| − | |||
| − | The directory is a list of files, each with name, offset and size of the file. The values for offset and size have to be ''multiplied by 2048'', since files are aligned to 2 KB boundaries. This means that even a file with only 123 byte content will take up 2 KB in the archive. | ||
First you have to find out the <strong>number of entries (n)</strong>. | First you have to find out the <strong>number of entries (n)</strong>. | ||
| − | Just divide the filesize of the .dir file by 32 and you will get it. | + | Just divide the filesize of the <code>.dir</code> file by 32 and you will get it. |
There is no Header, like in V2 (San Andreas) Files! | There is no Header, like in V2 (San Andreas) Files! | ||
| Line 21: | Line 19: | ||
24 byte - CHAR[24] - name of file | 24 byte - CHAR[24] - name of file | ||
| − | The .img file itself has no special structure or header, just all the files in 2 KB blocks. | + | The <code>.img</code> file itself has no special structure or header, just all the files in 2 KB blocks. |
| − | == Version 2 - GTA SA == | + | === Version 2 - GTA SA === |
| − | Version 2 archives, introduced with GTA San Andreas, combine .dir and .img files into one .img file. The directory has the same format as in version 1, but is located at the beginning of the archive. Files are again aligned to 2 KB boundaries. File offsets are relative to the start of the whole archive, not to the end of the file list. | + | Version 2 archives, introduced with GTA San Andreas, combine <code>.dir</code> and <code>.img</code> files into one <code>.img</code> file. The directory has the same format as in version 1, but is located at the beginning of the archive. Files are again aligned to 2 KB boundaries. File offsets are relative to the start of the whole archive, not to the end of the file list. |
Header:<br> | Header:<br> | ||
| Line 37: | Line 35: | ||
A major drawback of this format is the complicated extendability. If you have to add many files, it might happen that you run out of space for the directory, and have to move the first file(s) to the end. | A major drawback of this format is the complicated extendability. If you have to add many files, it might happen that you run out of space for the directory, and have to move the first file(s) to the end. | ||
| − | [[Category:Other Formats]][[Category:GTA 3]][[Category:GTA VC]][[Category:GTA SA]] | + | === Version 3 - GTA IV === |
| + | |||
| + | GTA IV introduced yet another <code>.img</code> file format. | ||
| + | ''This section is yet to be written...'' | ||
| + | |||
| + | |||
| + | {{file-stub}} | ||
| + | [[Category:Other Formats]][[Category:GTA 3]][[Category:GTA VC]][[Category:GTA SA]][[Category:GTA 4]] | ||
Revision as of 02:39, 20 August 2008
GTA's most commonly used archive files are known by the extension .img. They have a very simple format and currently exist in multiple versions.
Structure
Version 1 - GTA III & VC
Version 1 archives, used in GTA III and Vice City, are actually split up into two files: the content directory (.dir) and the actual archive (.img).
The directory is a list of files, each with name, offset and size of the file. The values for offset and size have to be multiplied by 2048, since files are aligned to 2 KB boundaries. This means that even a file with only 123 byte content will take up 2 KB in the archive. Files are stored (usually) unsorted, uncompressed and linear (no directory tree).
First you have to find out the number of entries (n).
Just divide the filesize of the .dir file by 32 and you will get it.
There is no Header, like in V2 (San Andreas) Files!
Entry: (repeated n times)
4 byte - DWORD - offset of file inside archive (in blocks) 4 byte - DWORD - size of file (in blocks) 24 byte - CHAR[24] - name of file
The .img file itself has no special structure or header, just all the files in 2 KB blocks.
Version 2 - GTA SA
Version 2 archives, introduced with GTA San Andreas, combine .dir and .img files into one .img file. The directory has the same format as in version 1, but is located at the beginning of the archive. Files are again aligned to 2 KB boundaries. File offsets are relative to the start of the whole archive, not to the end of the file list.
Header:
4 byte - CHAR[4] - FourCC, always "VER2" 4 byte - DWORD - number of entries (n)
Entry: (repeated n times)
4 byte - DWORD - offset of file inside archive (in blocks) 4 byte - DWORD - size of file (in blocks) 24 byte - CHAR[24] - name of file
A major drawback of this format is the complicated extendability. If you have to add many files, it might happen that you run out of space for the directory, and have to move the first file(s) to the end.
Version 3 - GTA IV
GTA IV introduced yet another .img file format.
This section is yet to be written...
