wdrdecode [-w wavelet] [-b boundary] [-pw pcpfile] [-m mask] [-r rate] bitstream imgfile
The transform is either the usual discrete wavelet transform (DWT) or a shape-adaptive DWT (SA-DWT); see imgdwt(1) for complete details. Option -w specifies the wavelet, option -b specifies the boundary extension, and option -pw indicates whether perceptual weighting is to be used. The -m option gives the image file to be used as a transparency mask for the SA-DWT. mask must be a grayscale image in which black in this image indicates transparency, white indicates full opacity, and gray tones are degrees of translucence (see QccAlpha(3) ). If the -m option is not given, the usual DWT is used.
The desired bitrate of the output bitstream is specified by rate, which is expressed in bits per pixel of the original image. wdrencode normally prints to stdout a small amount of information concerning this target bitrate and the actual bitrate achieved. Usually these rates are identical, but may differ slightly. If the -vo (value-only) option is given, all printed output is suppressed except for the actual bitrate.
wdrdecode performs the corresponding decoding using the WDR algorithm, decoding the bitstream made by wdrencode and producing a reconstructed image, imgfile. For sane results, wavelet, boundary, and pcpfile should be the same as they were for wdrencode, and mask should be the same if an SA-DWT was used as the transform. If a decoding rate is specified with the -r option, then wdrdecode stops decoding when rate bits per pixel from the input bitstream have been decoded. Otherwise, decoding stops when the end of the input bitstream is reached.
wdrencode and wdrdecode call QccWAVwdrEncode(3) and QccWAVwdrDecode(3) , respectively, to perform WDR encoding and decoding. Refer to the man pages of these functions for more information.
J. Tian and R. O. Wells, Jr., "Embedded Image Coding Using Wavelet Difference Reduction", in Wavelet Image and Video Compression, P. N. Topiwala, Ed., pp. 289-302, Kluwer Academic Publishers, Norwell, MA, 1998.
Copyright (C) 1997-2021 James E. Fowler