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Hi Tim,
I have released version 2.1.5 of bmeps which can use a predictor when producing PDF. You can run
bmeps -lpdf,predictor=tiff image.png image.pdf
Predictors are tiff, png-sub, png-up, png-average and png-paeth. See
http://bmeps.sourceforge.net/faq.html#predictor
for details.
The ASCII-85-encoding can not be removed easily as it is in the middle
of the encoding filters...
2010-01-04 16:13:16 UTC by kraused
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kraused made 1 file-release changes.
2010-01-04 16:02:01 UTC by kraused
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kraused made 1 file-release changes.
2010-01-04 16:01:04 UTC by kraused
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Hi Tim,
the PNG file format does not just use flate compression, it can use palettes and
prediction filters additionally which are not implemented in bmeps.
For information about prediction filters see
http://www.libpng.org/pub/png/pngintro.html
The PDF file format specification mentions prediction filters, but the description is not
detailed, so I hope I find more details somewhere...
2009-12-17 16:12:27 UTC by kraused
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kraused made 1 file-release changes.
2009-12-15 17:07:02 UTC by kraused
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Dirk,
Thanks for the quick response!
JPEGs: Yes, the ASCII85 encoding would certainly account for the majority of the overhead. Is there any way to have the option to output binary instead? 25%-28% is A LOT of overhead, especially for large (several MB) images. I would gladly trade the ability to edit my pdfs in a text editor in exchange for 25% compression. I guess this is more of a feature...
2009-11-23 20:41:12 UTC by nobody
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Hi Tim,
for JPEG files bmeps applies an additional ASCII-85-encoding to the DCT encoded data to produce 7-bit output (text which can be edited in a text editor).
So the 28% increase are normal.
For PNG images I would expect the same 25% growth when convverting to PS or EPS level 3 (which can use deflate). For levels 1 and 2 (2 is the default level produced by bmeps) deflate compression is not...
2009-11-23 12:22:01 UTC by kraused
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bmeps produces extremely large file sizes for pdf output. For example, when converting jpeg images, the files I tested created pdfs about 28% larger than the original jpeg file. Since bmeps is just passing through the existing jpeg data and wrapping it in a pdf, the files pdf files generated should not be much larger than the original jpegs. For comparison, sam2p produced pdfs that were less...
2009-11-23 03:40:27 UTC by nobody
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kraused changed the bmeps-2.1.3 file release.
2009-07-20 08:33:09 UTC by kraused
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kraused added the bmeps-2.1.3.tar.gz file.
2009-07-20 08:32:55 UTC by kraused
