DLI v1.1 has 3 new features:
1) An optimize for visual quality mode
2) Support for encoding full chrominance channels
3) Support for grayscale images
Optimize for visual quality
This is the default mode in the current software implementation. Compared with -or mode,
this mode sacrifices a few percent (typically 0-6%) of MSE performance for visual
characteristics that are generally superior. The images can be described as smoother and
having a more natural appearance. The following images illustrate the different appearances
of the 2 modes.
Magnified and cropped section of Barbara image compressed ~100:1 by each mode.
 
Default quality mode Minimal MSE mode
Magnified and cropped section of kodim23 image compressed ~200:1 by each mode.
  Default quality mode Minimal MSE mode
Encoding full chroma channels
While the use of chroma downsampling in DLI generally results in better quality images, there
are situations where full chroma is desired. Noteworthy, DLI's full chroma mode hasn't been as
optimized for compression as the default downsampling mode.
Encoding grayscale images
While most images in use are in color, there are applications which use grayscale images.
A side benefit of this feature is easy comparison with experimental image codecs in the research
community since they often only support grayscale images. DLI has been optimized for color
image compression however, and does particularly well with chroma data so comparing strictly
with grayscale images does not showcase DLI's potential. Having said that, DLI still performs
significantly better than current state-of-the-art codecs on grayscale images.
Software and options used for grayscale comparison
DLI v1.1
DLI c -or -q # input.pgm image.dli
DLI d image.dli output.pgm
JasPer v1.900.1 JPEG2000 software
jasper --input input.pgm --output image.jp2 -O rate=#
jasper --input image.jp2 --output output.pgm
Kakadu v6.1 JPEG2000 software
kdu_compress -i input.pgm -o image.jp2 -rate #
kdu_expand -i image.jp2 -o output.pgm
IJG JPEG v6b
cjpeg -o -q # input.pgm > image.jpg
djpeg image.jpg > output.pgm
HD Photo (WMP) DPK v1.0
wmpencapp -c 2 -i input.pgm -o image.wdp -q #
wmpdecapp -i image.wdp -o output.pgm
Images used
Lena (512x512 gray) and Barbara (512x512 gray) images found at http://ponomarenko.info/adct.htm (testset1.zip)
Lena (512x512 gray) Results
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DLI v1.1 Details |
