[Tutorial] Ecm tools (What is Ecm?)

[Cocona]

Credits goes to Neil Corlett.

You may have noticed that some of the games on our forum have a file extension--a suffix if you will--of ".ecm". If you are unaware of how to reverse the process, please read this.

Introduction
------------

The ECM format allows you to reduce the size of a typical CD image file
(BIN, CDI, NRG, CCD, or any other format that uses raw sectors; results may
vary).

It works by eliminating the Error Correction/Detection Codes (ECC/EDC) from
each sector whenever possible. The encoder automatically adjusts to
different sector types and automatically skips any headers it encounters.

The results will vary depending on how much redundant ECC/EDC data is
present. Note that for "cooked" ISO files, there will be no reduction.


Setup / Usage
-------------

Compile ecm.c and unecm.c if necessary, or use the included Win32 EXE files.

Run ECM with no parameters to see a simple usage reference:

usage: ecm cdimagefile [ecmfile]

Where "cdimagefile" is the name of the CD image file, and "ecmfile"
(optional) is the name of the ECM file. If you don't specify ecmfile, it
defaults to cdimagefile plus a .ecm suffix.

UNECM works the same way, but in reverse:

usage: unecm ecmfile [outputfile]

"ecmfile" must end in .ecm. If outputfile is not specified, it defaults
to ecmfile minus the .ecm suffix.

Dummy guide
-----------

To uncompress:
1. Drag the image file .ecm to the program "unecm.exe"

To compress:
1. Drag the image file to the "ecm.exe"


And there you have it. Here are the tools you'll need. Ecm tools click
Mirror download: Click

Happy gaming.