Dj Vu

Does anyone out there use DjVu? It is supposed to be « a web-centric format and software platform for distributing documents and images ». It could be used to replace tiff, jpeg and gif, giving a « better » compression.

It also has an open source version.

I would mainly like to understand what a « better » compression is. Files are smaller, ok, but is their quality high enough? Or we loose too much information?

Did anyone try it?


5 réflexions au sujet de « Dj Vu »

  1. I have some experience using this file format. At the first glance, few years ago, I was amazed with this new (then) way of digitizing documents. I even tried to generate some files by myself. And yes, they were smaller than PDFs. Now the matter of size is not so important to me as quality, especially if one deals with images, not only the text. Yes, I think it causes the files loose the quality, as compared to PDF. Most DJVU files have OCR-ed text layer, which is great help, but since PDF files do the same trick… Some of Polish digital libraries use that format, some use PDF. I don’t really care which one I am using in my scholarly work when accessing primary sources, like scanned historical journals or books , unless, as I said, the question of an image is involved. When I try to extract an image for instance to enrich a PowerPoint for classes, it makes a difference if it is DJVU.

    1. Thank you. This is what I suspected. I was wondering if it’ happens something like what happens with jpgs. I mean, that every time you open a file you somehow damage its quality, which then become worse and worse with the use.

  2. FR
    Indépendamment des questions de compression, où je n’ai pas remarqué de fortes pertes, je me suis retrouvé plusieurs fois sur des documents via DjVu dont le faible usage que l’on pouvait en faire m’a déçu.
    En voici un exemple : http://www.archive.org/stream/prcisanalytique04chargoog/prcisanalytique04chargoog_djvu.txt
    De plus, il est souvent impossible ou très fastidieux de copier tout le texte ou de faire des recherches par mot clef. Certes, ce dernier point est lié au mode de numérisation.

    EN
    Beyond compression matters, where I didn’t remark big losses (but I didn’t check really), I arrived sometimes on documents accessibles by DjVu and was a bit disapointed by a week usability. I.e : http://www.archive.org/stream/prcisanalytique04chargoog/prcisanalytique04chargoog_djvu.txt
    Plus, you can’t copy full texts quite often nor seach by key word. Of course, this last point is much more related to the way digitization was made.

    1. Merci beaucoup, Dominique.
      Est-ce que vous avez vu aussi des photos numérisées et stockeés en DjVu?

  3. I saw several images in DjVu format. I cannot say for sure, but the quality seems unchanged, no better or worse than from other formats. The only advantage seems to be the size of the files. Very useful for big online collections or slow internet connections.

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