how to encode a message in a picture with python

It tells us that this is the start of the image. The very first marker we care about is FF D8.

This tells us how long that particular segment is.

Most of the markers are followed by length information for the particular marker segment. These markers define where some specific information in a file is stored. They are very crucial for making sense of a file and are used by programs like file (on Mac/Linux) to tell us details about a file. You can think of these markers as sort of like bookmarks. You might have to refer to this image quite a few times while reading this tutorial.Īt the very basic level, almost every binary file contains a couple of markers (or headers). It lists all different parts of a simple JPEG file. Let’s start with this nice image by Ange Albertini. You can find the modified code for this article on my GitHub repo. I will be basing my decoder on this MIT licensed code but will be heavily modifying it for increased readability and ease of understanding. I plan on changing that by showing you how a basic JPEG decoder works using Python 3. Even if you do write code, it is in C/C++ and not accessible to a wide group of people. You don’t implement any code to do the actual decompression and decoding. Why write another article on JPEG when there are already hundreds of articles on the internet? Well, normally when you read articles on JPEG, the author just gives you details about what the format looks like. We will not be covering all the nuances of the JPEG format (like progressive scan) but rather only the basic baseline format while writing our decoder. By the end of this article, you will have a much better understanding of how the JPEG algorithm compresses data and how you can write some custom Python code to decompress it. The JPEG images you see are mostly in the JFIF format (JPEG File Interchange Format) that internally uses the JPEG compression algorithm. One thing a lot of people don’t know is that JPEG is not a format but rather an algorithm. Hi everyone! 👋 Today we are going to understand the JPEG compression algorithm. Understanding and Decoding a JPEG Image using Python July 14, 2020

How to encode a message in a picture with python