Decode JPEG image

[activecat]

Dear gurus,

I try to decode jpg images as according to following steps:

1. Read the image file using ifstream

2. Decode the information (without any existing library)

3. Show the image on computer screen using SFML Sprite/Image. (sf::Image::SetPixel)


I am now able to perform step 1 and 3, but not step 2.
I couldn't find much information about step 2 by googling.
Any recommendation of where could I find related information..?

Thanks in advance.

[Peter87]

Are you not allowed to let SFML do the decoding?
http://www.sfml-dev.org/documentation/1.6/classsf_1_1Image.php#a7cf6316aa5d022e0bdd95f1e79c9f50b

[activecat]

I need to do the jpeg encoding/decoding by myself.
Later I will try to enhance the existing compression technique.
This is part of an academical research.
Thank you.