|TIFF and LibTiff Mailing List Archive|
LibTiff Mailing List
2015.01.25 16:34 "Re: How to generate JBIG encoded TIFFs?", by Yuriy Kaminskiy
Ludolf Holzheid wrote: > Hello List, > > I compiled libtiff with JBIG support, but I can't get tiffcp to write > the output JBIG encoded (and yes, the input is bi-level data). > > If I try to control the conversion with the -t/-s/-r/-l/-w flags, I > get varying error messages, but in no case tiffcp writes any output > (see log attached). > > Is this supposed to work? 1) litiff/tif_jbig.c only supports encoding and decoding single-strip JBIG images (implementation limitation, there are no such limitation in standard); tiled encoding is also not supported. 2) tif_jbig does not support anything other than 1 bit-per-sample, 1 samples-per-pixel, min-is-black or min-is-white and silently produces garbage for unsupported bps/spp combinations (also implementation limitation and bug); 3) when changing strip size, tiffcp uses by-scanline conversion, which is not supported by tif_jbig. So, you should first convert file to single-strip layout: tiffcp -r-1 test-in.tiff tmp.tiff ... and then recompress it to jbig: tiffcp -c jbig tmp.tiff test-out.tiff I've posted some patches for 2 and 3, but they were ignored so far.