hi all,how to design a jpeg decoder?

[chwei]

I have never completed so large a project?so when i was asked to complete the jpeg decoder,i was so nervous?
I find some source code from opencores but the arithgothm is so bad that it is not suitable for me.
now i expected some poits and help from you all;

Thank you!!

 

[Sceadwian]

Does it have to be an FPGA? Use an external decoder.

 

[chwei]

Yes,i must complete it by using FPGA.
i expect your further answer for i have no idea now.
Thank you all the same for your reply.

 

[Iouri]

Why don't you buy core from somebody????

**broken link removed**

 

[chwei]

yes,thank you.
But I try to complete the core by myself. just for studing. i have few reference on hand.

 

[jjohn]

In computing, JPEG (pronounced JAY-peg) is a commonly used standard method of lossy compression for photographic images. The file format which employs this compression is commonly also called JPEG; the most common file extensions for this format are .jpeg, .jfif, .jpg, .JPG, or .JPE although .jpg is the most common on all platforms.

JPEG itself specifies only how an image is transformed into a stream of bytes, but not how those bytes are encapsulated in any particular storage medium. A further standard, created by the Independent JPEG Group, called JFIF (JPEG File Interchange Format) specifies how to produce a file suitable for computer storage and transmission (such as over the Internet) from a JPEG stream. In common usage, when one speaks of a "JPEG file" one generally means a JFIF file, or sometimes an Exif JPEG file. There are, however, other JPEG-based file formats, such as JNG, and the TIFF format can carry JPEG data as well.

JPEG/JFIF is the format most used for storing and transmitting photographs on the World Wide Web. For this application, it is preferred to formats such as GIF, which has a limit of 256 distinct colors that is insufficient for colour photographs, and PNG, which produces much larger image files for this type of image. It is not as well suited for line drawings and other textual or iconic graphics because its compression method performs badly on these types of images, for which the PNG and GIF formats are more commonly used.









http://www.jpeg.org/
http://www.faqs.org/faqs/jpeg-faq/

 

[salma ali bakr]

why don't u find out about the main blocks that make up the system and make ur own algorithms for each one

it won't be more than mutliplications, divisions....etc

 

[JaneZhong]

maybe the important thing is to design the HUFFMAN decoder arithgothm on FPGA.

 

[chwei]

maybe the important thing is to design the HUFFMAN decoder arithgothm on FPGA.

:|Yes,I have finished the 2-IDCT module,but HUFFMAN decoder I think will be the most difficult. I will be able to finish the module inverse_quantization,the Run length decoder,but then the inverse packer module will be difficult.

 

[mydreamhouse]

down a jpeglib and edit the soucecode

 

[scud]

hi.. i hope u have completed ur project in whole success....
Now i have started the project on Image compression...
Please will u help me in the overall Blocks... and finalizing the design...
Iam new to DSp... but have a very good knoledge on FPGAs..
Please if you have any material or cores plz do mail me at Dhinu_pp@rediffmail.com