because studying PDF compress, I collected some open source Jbig2 Encoder and Decoder.
This encoder can:
- Generate JBIG2 files, or fragments for embedding in PDFs
- Generic region encoding
- Perform symbol extraction, classification and text region coding
- Perform refinement coding and,
- Compress multipage documents
Lossless JBIG2 Encoder Windows Dynamic Libary: bases on Jbig2, but easily integrate with your own application.
The JPedal JBIG2 Image Decoder is a 100% pure Java image decoder for the JBIG2 file format. The decoder takes the JBIG2 image processing technology developed for the Java PDF viewer and makes it available as a generic library for more general usage.
It offers the ability to allow developers to add JBIG2 image rendering capabilities to their own applications, through a simple and easy to use API. In its simplest form it allows developers to load in a JBIG2 encoded datastream and convert that into a BufferedImage.
Version 1 is available under a BSD license to provide a JBig2 decoder. It is used in many projects, including some of our competitors.
Version 2 is a faster, enhanced version available under a commerical license only. It is used in the commercial versions of JPedal from 4.21 onwards.
jbig2dec is a decoder implementation of the JBIG2 image compression format. JBIG2 is designed for lossy or lossless encoding of ‘bilevel’ (1-bit monochrome) images at moderately high resolution, and in particular scanned paper documents. In this domain it is very efficient, offering compression ratios on the order of 100:1.
This is a decoder only implementation, and currently is in the alpha stage, meaning it doesn’t completely work yet. However, we are maintaining parity with available encoders, so it is useful for real work.
The Java ImageIO plugin for JBIG2 enables access to images encoded using the JBIG2 image compression standard.
The key features of the plugin are:
- Read-only (decode) support for images encoded using the JBIG2 standard, aka ITU T.88 and ISO/IEC 14492.
- Full support for all features defined in the standard, including arithmetic coding, Huffman coding and MQ coding.
- Pure Java code. No funny native or JNI stuff required.
- Production quality. Robust and well-tested.
- Reasonable performance.
- Standard ImageIO API.
- Support for shared data segments as used by PDF via custom DecodeParams.
JBIG-KIT is a software implementation of the JBIG1 data compression standard (ITU-T T.82), which was designed for bi-level high-resolution image data such as scanned documents. This library is available in portable C code and has been widely used in fax products, printer firmware and drivers, and document management systems. The package includes a variant implementation of just the ITU-T T.85 profile, with memory management optimized for embedded and fax applications.
JBIG2 is an image compression standard for bi-level images, developed by the Joint Bi-level Image Experts Group. It is suitable for both lossless and lossy compression. According to a press release from the Group, in its lossless mode JBIG2 typically generates files one third to one fifth the size of Fax Group 4 and one half to one quarter the size of JBIG, the previous bi-level compression standard released by the Group. JBIG2 has been published in 2000 as the international standard ITU T.88, and in 2001 as ISO/IEC 14492.