Comparison with econvert (ExactImage)

mara0004 commented

2022-05-17 20:35:04 +00:00

Contributor

Hi,

I'd be curious to know how img2pdf performs compared to econvert from ExactImage, which is some kind of image processing library that aims to be a faster alternative to ImageMagick. You can use it like this:

econvert -i some_image.jpg -o econvert_output.pdf

The corresponding Debian packages are called exactimage and python3-exactimage for the Python bindings.

Thanks!

Hi, I'd be curious to know how img2pdf performs compared to `econvert` from [ExactImage](http://www.exactcode.com/opensource/exactimage/), which is some kind of image processing library that aims to be a faster alternative to ImageMagick. You can use it like this: ```bash econvert -i some_image.jpg -o econvert_output.pdf ``` The corresponding Debian packages are called `exactimage` and `python3-exactimage` for the Python bindings. Thanks!

josch commented

2022-05-18 04:48:55 +00:00

Owner

Like pdflatex and podofoimg2pf it seems that econvert is able to embed JPEG images into PDF directly without re-encoding but when given other file formats stores them just using flate compressen, which unnecessarily increases the filesize. Furthermore, it throws an error with CMYK TIF input:

TIFCodec: Unrecognized photometric: 5
Error reading input file src/tests/input/CMYK.tif, image: 0
Error: 1 filename(s) left for writing

It also doesn't store CMYK jpeg files as CMYK but converts them to RGB, so it's not lossless. When trying to feed it 16bit files, it errors out with Unhandled bps/spp combination. It also seems to choose JPEG encoding when using it on some file types (like palette images) making it again not lossless.

Like pdflatex and podofoimg2pf it seems that econvert is able to embed JPEG images into PDF directly without re-encoding but when given other file formats stores them just using flate compressen, which unnecessarily increases the filesize. Furthermore, it throws an error with CMYK TIF input: ``` TIFCodec: Unrecognized photometric: 5 Error reading input file src/tests/input/CMYK.tif, image: 0 Error: 1 filename(s) left for writing ``` It also doesn't store CMYK jpeg files as CMYK but converts them to RGB, so it's not lossless. When trying to feed it 16bit files, it errors out with `Unhandled bps/spp combination`. It also seems to choose JPEG encoding when using it on some file types (like palette images) making it again not lossless.

mara0004 commented

2022-05-18 09:33:16 +00:00

Author

Contributor

Thanks!