What's new in libjpeg 9
Jan 28, 2013
- Add cjpeg -rgb1 option to create an RGB JPEG file, and insert a simple reversible color transform into the processing which significantly improves the compression.
- The recommended command for lossless coding of RGB images is now cjpeg -rgb1 -block 1 -arithmetic.
- As said, this option improves the compression significantly, but the files are not compatible with JPEG decoders prior to IJG v9 due to the included color transform.
- The used color transform and marker signaling is compatible with other JPEG standards (e.g., JPEG-LS part 2).
- Remove the automatic de-ANSI-fication support (Automake 1.12).
- Add remark for jpeg_mem_dest() in jdatadst.c.
- Support files with invalid component identifiers (created by Adobe PDF).
- Adapt full buffer case in jcmainct.c for use with scaled DCT.
- Add type identifier for declaration of noreturn functions.
- Correct argument type in format string, avoid compiler warnings.
- Add missing #include directives in configuration checks, avoid configuration errors.
New in libjpeg 8d (Jan 18, 2012)
- Add cjpeg -rgb option to create RGB JPEG files.
- Using this switch suppresses the conversion from RGB colorspace input to the default YCbCr JPEG colorspace. This feature allows true lossless JPEG coding of RGB color images
- The recommended command for this purpose is currently cjpeg -rgb -block 1 -arithmetic.
- SmartScale capable decoder (introduced with IJG JPEG 8) required.
- Add option to disable the region adjustment in the transupp crop code.
New in libjpeg 8c (Jan 18, 2012)
- Add option to compression library and cjpeg (-block N) to use
- different DCT block size.
- All N from 1 to 16 are possible. Default is 8 (baseline format).
- Larger values produce higher compression,
- smaller values produce higher quality.
- SmartScale capable decoder (introduced with IJG JPEG 8) required.
New in libjpeg 8b (Jan 18, 2012)
- Repair problem in new memory source manager with corrupt JPEG data.
- Repair problem in Makefile.am test target.
- Support MinGW installation with automatic configure.
New in libjpeg 8a (Jan 18, 2012)
- Writing tables-only datastreams via jpeg_write_tables works again.
- Support 32-bit BMPs (RGB image with Alpha channel) for read in cjpeg.
- Improve accuracy in floating point IDCT calculation.
New in libjpeg 8 (Jan 18, 2012)
- jpegtran now supports the same -scale option as djpeg for "lossless" resize.
- An implementation of the JPEG SmartScale extension is required for this feature. A (draft) specification of the JPEG SmartScale extension is available as a contributed document at ITU and ISO. Revision 2 or later of the document is required (latest document version is Revision 3).
- The SmartScale extension will enable more features beside lossless resize in future implementations, as described in the document (new compression options).
- Add sanity check in BMP reader module to avoid cjpeg crash for empty input image
- Add data source and destination managers for read from and write to
- memory buffers. New API functions jpeg_mem_src and jpeg_mem_dest.