On Sat, May 22, 2021 at 2:33 PM Thomas Schmitt <scdbac...@gmx.net> wrote:
> Hi, > > Charlie Gibbs wrote: > > <filename>: Unsupported JPEG process: SOF type 0xc2 > > My xv reports this on Progressive JPEG images like > http://www.reasoft.com/tutorials/web/img/progress.jpg > > My xv binary stems from source xv-3.10a.tar.gz of june 2000. > Its Makefile indicates that it gets linked statically with a libjpeg.a > which the source tarball brings in subdirectory ./jpeg. > > The file jpeg/jdmarker.c in this libjpeg copy emits the error for many SOF > types. See line 771 ff. and JERR_SOF_UNSUPPORTED in jpeg/jerror.h. > > In contrast to that, the library > /usr/lib/x86_64-linux-gnu/libjpeg.a > of package libjpeg62-turbo-dev supports SOF2: > > https://sources.debian.org/src/libjpeg-turbo/1:2.0.6-4/jdmarker.c/?hl=1000#L1000 > > So an adventurous programmer could try to trick the old xv into linking > Debian's libjpeg.a, or could try to replace the source in xv's ./jpeg by > the > source of Debian's libjpeg-turbo. > > > ---------------------------------------------------------------------------- > > My personal solution is different, as i find xv's display of oversized > images > abysmal, while the beautiful results of ImageMagic's "convert" can cost > gigabytes of RAM if the input is large enough. > So i created a program based on libjpeg which reads JPEGs line by line > and emits the resized result line by line. The resizer works with a > discrete rectangular pixel model rather than a continous space. > > As windfall profit this program can read progressive JPEGs with SOF2 and > stores its results as sequential JPEGs which xv can read. > > (I can provide its source code under BSD license if no better converter > can be found.) > > > Have a nice day :) > > Thomas > > Thomas, that sounds awesome, please do post somewhere (and provide a link here, if you would be so kind). I would like to try it out, and i'll bet others would too. dan
