Editing ROM hacking (section)

===Hex editing===
A [[hex editor]] is one of the most fundamental tools in any ROM hacker's repertoire. Hex editors are usually used for editing text, and for editing other data for which the structure is known (for example, item properties), and [[#Assembly hacking|Assembly hacking]].

Editing text is one of the most basic forms of hacking. Many games do not store their text in [[ASCII]] form, and because of this, some specialized hex editors have been developed, which can be told what byte values correspond to what letter(s) of the alphabet, to facilitate text editing; a file that defines these byte=letter relationships is called a "table" file. Other games use simple text compression techniques (such as [[byte pair encoding]], also called [[dual tile encoding]] or DTE, in which certain combinations of two or more letters are encoded as one byte) which a suitably equipped hex editor can facilitate editing.

A hex editor is the tool of choice for editing things such as character/item properties if the structure and location of this data are known and there is no game-specific editor for the game that can edit this information. Some intrepid hackers also perform [[#Level editing|level editing]] with a hex editor, but this is extremely difficult (except on games whose level storage format closely resembles how it is presented in a hex editor).