Is there a place to find how file types are formatted?

Question

I've been looking around the internet to find a place where I could see how certain file types are made so I can understand them better and read them in some applications I want to make.

For instance, I can't find a place that describes how a .epub file is made.

What I'd like to know is how I'm supposed to approach a problem like this. Is it better to find a document with the file format specifications and build an application that will read it and implement some other functions or is there an easier approach? How do people generally create applications that can do just that?

I'm wondering because I can't find the said documents I'm searching for, only some information here and there that don't really tell me much.

Maybe I'm just not searching for the correct terms in search engines, but I'm clueless on how to start if I can't even find how .epub files are supposed to be read.

What I'd really like is an answer that tells me how to find such documents for most file types, but don't be afraid to give me an answer if you don't know, but know where to find the .epub file format specs since that's what I need the most at the moment.

Answer 1

There was this great site -www.wotsit.org- but now almost all links are dead and admin is not responding to emails. So I usually try this in google rar specification rar file format And if format is quite popular I find better or worse specs this way. Ocassionally Wikipedia can have format specification in the links section on the bottom of the article. When I find nothing that way and there used to be something on Wotsit then I copy the name of file from wotsit and search on google and once in a while I can find format spec that way.

Answer 2

Is it better to find a document with the file format specifications and build an application that will read it and implement some other functions or is there an easier approach?

Yes... you need to find the specifications for that specific file format. There is not a repository somewhere for different unrelated formats.

A simple search of google will often reveal if there is already a publicly available spec: https://encrypted.google.com/search?hl=en&q=epub%20file%20specification

It's also helpful to look at wikipedia: http://en.wikipedia.org/wiki/EPUB

At the bottom of the article on wikipedia, you can find the following links:

EPUB Format Construction Guide

Format Overview of the EPUB File

The first link looks like what you are interested in. The second link is a video, which I did not watch, but the text of the link on wikipedia was promising.