7 ms·

This may be an acceptable format for some electronic versions of scanned books, but it's not a "PDF Alternative". Also PDF is an open format.

chungy 8y ago
PDF wasn't an open format when DjVu was first created. Now that it is, there's probably no reason to use DjVu.
- ummonk 8y ago
  PDF is great for electronically created documents. DjVu is far superior for scanned documents, though. It compresses much smaller and DjVu viewers are far more performant at scrolling through large scanned documents.
  - Hello71 8y ago
    even compared to MuPDF? PDF.js is well known to be very slow, and even poppler is pretty slow compared to MuPDF.
    - zokier 8y ago
      I still prefer Adobe Acrobat Reader despite everything, and absolutely hate PDF.js because it seems to take like few seconds to render a page when jumping around, whereas Adobe Acrobat Reader is pretty much interactive. Nevermind the fact that pdf.js has still problems rendering quite many documents I encounter, while Acrobat is basically the de-facto reference implementation for PDFs. btw if you want quickly some random large scanned PDFs for testing, archive.org is a goldmine. For example here is a scanned 1200 electronics handbook: https://archive.org/details/NationalSemiconductorLinearApplicationsHandbook1994 https://archive.org/details/NationalSemiconductorLinearAppli... They also do DjVu, so you can see the size difference there. For that particular book, its 58M for the PDF vs 31M for DjVu. So basically half the size.
    - pmoriarty 8y ago
      I use mupdf all the time for PDFs. It's much faster than PDF.js, but still much, much slower than djvu for scanned documents.
  - hsivonen 8y ago
    In what circumstances does it actually matter to be able to get better compression than CCITT Group 4? For example, when is size such a deciding factor that it makes sense to forgo the compatibility of CCITT Group 4 in PDF and to use something else like JBIG2 in PDF or DjVu [assuming the latter actually is smaller; I didn't measure]?

chungy 8y ago

PDF wasn't an open format when DjVu was first created. Now that it is, there's probably no reason to use DjVu.

ummonk 8y ago
PDF is great for electronically created documents. DjVu is far superior for scanned documents, though. It compresses much smaller and DjVu viewers are far more performant at scrolling through large scanned documents.
- Hello71 8y ago
  even compared to MuPDF? PDF.js is well known to be very slow, and even poppler is pretty slow compared to MuPDF.
  - zokier 8y ago
    I still prefer Adobe Acrobat Reader despite everything, and absolutely hate PDF.js because it seems to take like few seconds to render a page when jumping around, whereas Adobe Acrobat Reader is pretty much interactive. Nevermind the fact that pdf.js has still problems rendering quite many documents I encounter, while Acrobat is basically the de-facto reference implementation for PDFs. btw if you want quickly some random large scanned PDFs for testing, archive.org is a goldmine. For example here is a scanned 1200 electronics handbook: https://archive.org/details/NationalSemiconductorLinearApplicationsHandbook1994 https://archive.org/details/NationalSemiconductorLinearAppli... They also do DjVu, so you can see the size difference there. For that particular book, its 58M for the PDF vs 31M for DjVu. So basically half the size.
  - pmoriarty 8y ago
    I use mupdf all the time for PDFs. It's much faster than PDF.js, but still much, much slower than djvu for scanned documents.
- hsivonen 8y ago
  In what circumstances does it actually matter to be able to get better compression than CCITT Group 4? For example, when is size such a deciding factor that it makes sense to forgo the compatibility of CCITT Group 4 in PDF and to use something else like JBIG2 in PDF or DjVu [assuming the latter actually is smaller; I didn't measure]?