Command line option -split-dc-scan is added to code DC scans
independently (instead of interleaved). It should be determined whether
this option introduces any decoder compatibility issues ( see #83 )
Option -multidcscan is renamed to -opt-dc-scan
Add option to apply trellis quantization to the DC coefficients ( see
#57 ). May need further refinement to make sure block order during
trellis optimization matches order during coding.
Add macro JPEG_RAW_READER that defines whether to pass RAW sample data
from input to output JPEG files (hence preserving color space and
sampling). Macro is now disabled by default.
Add code to copy metadata from input to output JPEG, hence preserving
color profiles and other important information
Value of cinfo->one_dc_scan is set to true by default to use a single
DC scan for all components.
Option -onedcscan is replaced by -multidcscan to enable multiple DC
scans.
While this change appears to degrade compression performance it
improves compatibility with a wider range of JPEG decoders.
Add option to have a single DC scan wherein all components are
interleaved when using progressive mode. This may resolve compatibility
issues raised in #29 and #48.
This option is available through -onedcscan in cjpeg
Different lambda values may be used for each frequency in DCT domain.
The weighting table is currently not configurable but can be
enabled/disabled with cinfo-> use_lambda_weight_tbl
-tune-psnr, -tune-ssim and -tune-hvs-psnr are added to cjpeg to control
the trellis quantization process and optimize output for PSNR, SSIM and
HVS-PSNR distortion metrics
A new pass type trellis_pass is added. It defines a pass where trellis
quantization is done in the quantize_trellis() function.
Trellis quantization can be enabled by setting use_moz_defaults to 2 or
by using the -trellis option in cjpeg
Note that trellis does currently not work with scan optimization. Scan
optimization is disabled when trellis is enabled.
Add the fast mode of jpgcrush where:
- Huffman table optimisation is enabled
- Progressive coding mode is enabled
- New default scans are defined for progressive coding
