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It is a pity that DjVu[0] wasn't even mentioned; an open format that was superior to PDF in many ways[1], including better optimization, efficient storage. [0]

It is a pity that DjVu[0] wasn't even mentioned; an open format that was superior to PDF in many ways[1], including better optimization, efficient storage. [0] http://djvu.org/ http://djvu.org/ [1] https://en.wikipedia.org/wiki/DjVu https://en.wikipedia.org/wiki/DjVu

adamnemecek 6y ago
It's crazy that Yann LeCun was involved in the creation.
- ar7hur 6y ago
  Yes, Yann and another machine learning celebrity: Leon Bottou!
msla 6y ago
DjVu is a great format for scanned images, which is its primary use-case, but I'm not seeing where you can have actual, selectable text in a DjVu document, like you can with PDF and PostScript. It seems like it's all images.
- adrian_b 6y ago
  I have not read the specification, but the DJVu format must have a way to store the plain text besides the images and that way is frequently used. I do not remember ever reading a DJVu file that did not allow searching and selecting the text, while PDF files which do not allow those, because they store only the scanned images, are quite frequent.
- jwilk 6y ago
  > 3.3.2 Hidden text > Every DjVu image optionally includes a hidden text layer that associated graphical features with the corresponding text. The hidden text layer is usually generated by running Optical Character Recognition software. This textual information provides for indexing DjVu documents and copying/pasting text from DjVu page images. I copied that text from the DjVu spec, which is in the DjVu format.
saagarjha 6y ago
I don't see how DjVu solves vector graphics, which is a pretty important usecase for PDF.
BelleOfTheBall 6y ago
Man, I haven't seen a DjVu file in years. It used to be somewhat common in scans of magazines and other media that relied on images. Pity that it didn't catch on, although I suppose it still could, if some of its benefits were refined. I find that larger PDFs tend to tank optimization, is that a problem for DjVu files at all?

adamnemecek 6y ago

It's crazy that Yann LeCun was involved in the creation.

ar7hur 6y ago
Yes, Yann and another machine learning celebrity: Leon Bottou!

msla 6y ago

DjVu is a great format for scanned images, which is its primary use-case, but I'm not seeing where you can have actual, selectable text in a DjVu document, like you can with PDF and PostScript. It seems like it's all images.

adrian_b 6y ago
I have not read the specification, but the DJVu format must have a way to store the plain text besides the images and that way is frequently used. I do not remember ever reading a DJVu file that did not allow searching and selecting the text, while PDF files which do not allow those, because they store only the scanned images, are quite frequent.
jwilk 6y ago
> 3.3.2 Hidden text > Every DjVu image optionally includes a hidden text layer that associated graphical features with the corresponding text. The hidden text layer is usually generated by running Optical Character Recognition software. This textual information provides for indexing DjVu documents and copying/pasting text from DjVu page images. I copied that text from the DjVu spec, which is in the DjVu format.

saagarjha 6y ago

I don't see how DjVu solves vector graphics, which is a pretty important usecase for PDF.

BelleOfTheBall 6y ago

Man, I haven't seen a DjVu file in years. It used to be somewhat common in scans of magazines and other media that relied on images. Pity that it didn't catch on, although I suppose it still could, if some of its benefits were refined. I find that larger PDFs tend to tank optimization, is that a problem for DjVu files at all?