Independent JPEG Group

lastmod 2020-06-30created 2016-01-059 edits

JPEG (Joint Photographic Experts Group) is a standard lossy compression method designed for still images. The standard was established by ISO and ITU-T. File formats that use JPEG are usually also called JPEG images and use extensions such as .jpg, .jpeg, and .jpe.

libjpeg

• Independent JPEG Group homepage
• Wikipedia (en) libjpeg description
• libjpeg usage sample example

libjpeg is a library written in C that implements decoding and encoding of JPEG files and is widely used around the world. The library was developed by the Independent JPEG Group.

Improving decoding speed

When using libjpeg, you can improve decoding speed by setting the following right before calling jpeg_start_decompress(). (However, quality degrades slightly.)

jpeg_read_header(&cinfo, TRUE);
// ...
cinfo.do_fancy_upsampling = FALSE;
cinfo.do_block_smoothing = FALSE;
cinfo.dct_method = JDCT_IFAST;
cinfo.dither_mode = JDITHER_ORDERED;
// ...
jpeg_start_decompress(&cinfo);

Local Download

IJG 9a of 19-Jan-2014

Jpegsrc.v9a.tar.gz (md5: 3353992aecaee1805ef4109aadd433e7)

C Code to convert JPEG to BMP in LINUX using libjpeg.

http://digitalpbk.blogspot.kr/2009/01/code-libjpeg-converting-jpeg-to-bmp.html

The following code converts JPEG file into BMP file. The code requires the libjpeg library. The following code is a good example of how to use the libjpeg library. Code converts colour jpeg to 24bit BITMAP.

• Compile: gcc jpeg2bmp.c -ljpeg -o jpeg2bmp
• Usage: jpeg2bmp source.jpg destination.bmp

See also

• Giflib
• libpng
• libjpeg_turbo
• image_magick: ImageMagick is free software used to create or edit graphic images.

Favorite site

• Independent JPEG Group web site
• libjpeg web site
• Wikipedia (en) JPEG description
• Structure of a jpeg file ¹

References