Difference between pages "GIF" and "Talk:Main Page"

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The '''Graphics Interchange Format''' ('''GIF''') (SM) format is a lossless [[image format]]. GIF images use internal [[LZW]] compression to reduce file size.  CompuServe created this format, which is a bitmap image format allowing 256 different colors to be selected from a 24-bit color palette (RGB).  GIF also allows for animations by sequencing through multiple GIF image data inside a single file.
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I am setting up a global directory of computer forensics analysts, and am looking for feedback to the idea. Although the directory is in the UK, I want it to be global. Any thoughts, please put them on Computer Forensics [http://www.computer-forensics.co.uk] in the forums section. Thanks and regards, Simon
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: Given the lack of response I'm not sure this is a viable idea. [[User:Jessek|Jessek]] 21:13, 26 February 2007 (PST)
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: Doesn't seem like a good idea to me. [[User:Simsong|Simsong]] 18:50, 15 March 2007 (PDT)
  
"The Graphics Interchange Format(c) is the Copyright property of CompuServe Incorporated. GIF(sm) is a Service Mark property of CompuServe Incorporated."
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== Hachoir framework ==
  
== Format ==
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Hi, I'm the author of [http://hachoir.org/ Hachoir], a generic framework for binary file manipulation. I don't know if I can add it in your wiki. I prefer to have your review first :-)
  
GIF files consist of a [[header]], image data, optional [[metadata]], and a [[footer]]. The header consists of a signature and a version, each 3 bytes long. The signature is <tt>47 49 46</tt> (hex) / <tt>GIF</tt> (text). The versions are either <tt>38 37 61</tt> or <tt>38 39 61</tt> (hex) / <tt>87a</tt> or <tt>89a</tt> (text) respectively. The footer or trailer (as identified in the format specification) is usually <tt>3B</tt> (hex).
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Hachoir supports many file formats (more than 60 formats) and have many features:
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  * Fault tolerant parser (truncated/buggy file or buggy parser)
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  * Smart syntax: you don't have to care about endian or charset, and you can mix byte and bit fields
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* Few functions to modify files
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* File recognition using header/footer in a disk image (in any file) with few false positive (each file is checked using the parser)
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  * Written in Python: OS independant and easy to script/extend
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* curses, wxWidgets and Gtk interfaces
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* Many programs based on hachoir-core and hachoir-parser:
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  * hachoir-strip: remove metadata and other "useless" informations
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  * hachoir-grep: find substring in a binary file (using hachoir parsers: so search is Unicode aware)
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  * hachoir-subfile: find all subfiles in a file
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  * etc.
  
Common file extensions are .gif and .GIF
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: Please add it. [[User:Simsong|Simsong]] 09:50, 15 March 2007 (PDT)
 
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== Metadata ==
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GIF89a files can contain [[metadata]] in [[text]] format.  GIF metadata is contained in sections identified as a Comment Extension, a Plain Text Extension, and an Application Extension.  All extension sections begin with the Extension Introducer <tt>21</tt> (hex).
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Comment Extensions are optional and more than one may be present.  They were designed to allow including comments about the graphic, credits, descriptions or other types of non-control/non-graphic data.  The beginning of this block has the Extension Introducer and a Comment Label <tt>FE</tt> (hex).  Comment data has a sequence of sub-blocks between 1 and 255 bytes in length, with the size in a byte before the data.  Comment Extensions should appear either before or after the control and graphic data blocks.
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Plain Text Extensions are optional and more than one may be present.  They were designed to allow rendering of textual data as a graphic.  The beginning of this block has the Extension Introducer and a Comment Label <tt>01</tt> (hex).  Plain text data has a sequence of sub-blocks between 1 and 255 bytes in length, with the size in a byte before the data.
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Application Extensions are optional. They were designed to allow applications to insert application specific data inside a GIF. The beginning of this block has the Extension Introducer and an Application Extension Label <tt>FF</tt> (hex). 
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== Externals Links ==
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* [http://en.wikipedia.org/wiki/GIF Wikipedia: GIF]
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* [http://www.w3.org/Graphics/GIF/spec-gif89a.txt W3.Org: GRAPHICS INTERCHANGE FORMAT SPECIFICATION]
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[[Category:File Formats]]
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Revision as of 21:50, 15 March 2007

I am setting up a global directory of computer forensics analysts, and am looking for feedback to the idea. Although the directory is in the UK, I want it to be global. Any thoughts, please put them on Computer Forensics [1] in the forums section. Thanks and regards, Simon

Given the lack of response I'm not sure this is a viable idea. Jessek 21:13, 26 February 2007 (PST)
Doesn't seem like a good idea to me. Simsong 18:50, 15 March 2007 (PDT)

Hachoir framework

Hi, I'm the author of Hachoir, a generic framework for binary file manipulation. I don't know if I can add it in your wiki. I prefer to have your review first :-)

Hachoir supports many file formats (more than 60 formats) and have many features:

* Fault tolerant parser (truncated/buggy file or buggy parser)
* Smart syntax: you don't have to care about endian or charset, and you can mix byte and bit fields
* Few functions to modify files
* File recognition using header/footer in a disk image (in any file) with few false positive (each file is checked using the parser)
* Written in Python: OS independant and easy to script/extend
* curses, wxWidgets and Gtk interfaces
* Many programs based on hachoir-core and hachoir-parser:
  * hachoir-strip: remove metadata and other "useless" informations
  * hachoir-grep: find substring in a binary file (using hachoir parsers: so search is Unicode aware)
  * hachoir-subfile: find all subfiles in a file
  * etc.
Please add it. Simsong 09:50, 15 March 2007 (PDT)