JPEG files

[Avss]

Can any one tell me by which algorithm, jpeg files are built. and can any one give me any idea of that.?

[hiren_mehta007]

The JPEG2000 compression algorithm was released by an ISO standardization committee in January 2001. It is based on the existing JPEG specifications and adds three important things to the existing standard:

-> It adds a wavelet-based algorithm to the existing JPEG compression algorithms. This wavelet-transformation algorithm offers improved image quality at very high compression ratios.
-> JPEG2000 is said to produce as much as a 20% improvement in compression efficiency over the current JPEG format.
-> It also offers an optional lossless compression mode. Lossless JPEG2000 files areabout half the size of the original.

[syamfamily]

Can any one tell me by which algorithm, jpeg files are built. and can any one give me any idea of that.?

The JPEG committee has created many standards since it was created in 1986. ISO had actually started to work on this 3 years earlier, in April 1983, in an attempt to find methods to add photo quality graphics to the text terminals of the time, but the 'Joint' that the 'J' in JPEG stands for refers to the merger of several groupings in an attempt to share and develop their experience.

The formal name of the standard that most people refer to as 'JPEG' is ISO/IEC IS 10918-1 | ITU-T Recommendation T.81, as the document was published by both ISO through its national standards bodies, and CCITT, now called ITU-T. IS 10918 has actually 4 parts -

Part 1 - The basic JPEG standard, which defines many options and alternatives for the coding of still images of photographic quality
Part 2 - which sets rules and checks for making sure software conforms to Part 1
Part 3 - set up to add a set of extensions to improve the standard, including the SPIFF file format
Part 4 - defines methods for registering some of the parameters used to extend JPEG
As well as the standard we created, nearly all of its real world applications require a file format, and example reference software to help implementors. These functions were added to our work by others - the file format was created originally by Eric Hamilton, the then convenor of JPEG as part of his work at C-Cube Microsystems, and was placed by them into the public domain under the name JFIF

for completely explanation, you can read on jpeg.org

[gdawe5]

Also check wiki for jpeg...if you get the chance used PNG, is smaller in size and compression is better

[harry]

JPEG stands For Joint Photograhic Enterprise Group
For compression: it follows beloe steps
First the image is divided into 8 by 8 blocks of pixels.
then similar colour pixels are removed but the effect can not be catched by man's eye.