3 ms·

I'd love to see some examples (especially if the scan appeared to be of good quality and not a grainy 100dpi affair). Do you have any idea what kinds of docume

I'd love to see some examples (especially if the scan appeared to be of good quality and not a grainy 100dpi affair). Do you have any idea what kinds of documents you were browsing when you found them?

deleted 4y ago
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jwilk 4y ago
https://news.ycombinator.com/item?id=17435514 https://news.ycombinator.com/item?id=17435514 (found via https://en.wikipedia.org/wiki/DjVu https://en.wikipedia.org/wiki/DjVu) There's apparently 22 pages of fluff at the beggining, so you should add that the page numbers. Also "the third line" was meant to be the 3rd line from the bottom. Direct links (to be opened in DjView): https://ia800204.us.archive.org/28/items/cu31924026442156/cu31924026442156.djvu?djvuopts&page=80&highlight=960,277,173,39 https://ia800204.us.archive.org/28/items/cu31924026442156/cu... https://ia800204.us.archive.org/28/items/cu31924026442156/cu31924026442156.djvu?djvuopts&page=442&highlight=983,1544,146,41 https://ia800204.us.archive.org/28/items/cu31924026442156/cu...
- richard_todd 4y ago
  Thanks! When I convert the jp2k file for that page 58 with ABBYY default ("balanced") jbig2 settings I don't get any of the errors we see in the examples. If I convert to DJVU and purposefully degrade the image to 150DPI, I still don't get the errors on display in this example. Besides the errors talked about in your linked discussion (germauic), the pdf clearly has many 'c' -> 'e' errors which aren't in the jp2k files. Again, I can't reproduce this with the software I use. I've also extensively used djvulibre and you just don't see errors like this from clean scans. So, I have to conclude that the original conversions were done with very aggressive settings (or very bad jbig2 implementations). If that's they way the internet archive did all its encodings, then I admit there must be several problem documents, and they should re-do the conversions from the original JP2k files they seem to have kept. Not sure if google books made similar mistakes.

deleted 4y ago

[deleted]

jwilk 4y ago

https://news.ycombinator.com/item?id=17435514 https://news.ycombinator.com/item?id=17435514 (found via https://en.wikipedia.org/wiki/DjVu https://en.wikipedia.org/wiki/DjVu) There's apparently 22 pages of fluff at the beggining, so you should add that the page numbers. Also "the third line" was meant to be the 3rd line from the bottom. Direct links (to be opened in DjView): https://ia800204.us.archive.org/28/items/cu31924026442156/cu31924026442156.djvu?djvuopts&page=80&highlight=960,277,173,39 https://ia800204.us.archive.org/28/items/cu31924026442156/cu... https://ia800204.us.archive.org/28/items/cu31924026442156/cu31924026442156.djvu?djvuopts&page=442&highlight=983,1544,146,41 https://ia800204.us.archive.org/28/items/cu31924026442156/cu...

richard_todd 4y ago
Thanks! When I convert the jp2k file for that page 58 with ABBYY default ("balanced") jbig2 settings I don't get any of the errors we see in the examples. If I convert to DJVU and purposefully degrade the image to 150DPI, I still don't get the errors on display in this example. Besides the errors talked about in your linked discussion (germauic), the pdf clearly has many 'c' -> 'e' errors which aren't in the jp2k files. Again, I can't reproduce this with the software I use. I've also extensively used djvulibre and you just don't see errors like this from clean scans. So, I have to conclude that the original conversions were done with very aggressive settings (or very bad jbig2 implementations). If that's they way the internet archive did all its encodings, then I admit there must be several problem documents, and they should re-do the conversions from the original JP2k files they seem to have kept. Not sure if google books made similar mistakes.