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Old 02-27-2021, 08:08 AM   #1855
willus
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VladimirS -- I have found that complex compressions such as JPEG 2000 (JP2/JPX) are usually the worst offenders for slower page turning times on readers. They make the PDF very small in size, but they take longer to decode. You can tell if your source PDF has these compressions by using this:

k2pdfopt -i source.pdf

In addition, complex layouts can also slow reading. That is why "-mode copy" works well for reducing the CPU load on the reader, because it converts each page into a bitmap using the standard "deflate" PDF compression which can quickly be decoded, with 4-bits-per-pixel gray level. In general, if the source PDF is slow to render and this is more important to you than the size of the document, converting to bitmaps with k2pdfopt should help, which is accomplished by being sure that native mode is turned off (-n-). The bits per pixel in the resulting bitmaps can be controlled with the -bpc option. The resolution of the bitmaps is most easily controlled with the -dr option. See my command-line usage page. I don't believe the version of the PDF inherently impacts the page turning time significantly, nor if the file has bookmarks.

Last edited by willus; 02-27-2021 at 08:12 AM.
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