syvaidya / openstego

OpenStego is a steganography application that provides two functionalities: a) Data Hiding: It can hide any data within an image file. b) Watermarking: Watermarking image files with an invisible signature. It can be used to detect unauthorized file copying.
https://www.openstego.com
GNU General Public License v2.0
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PNG transparency of cover file lost after data hiding, and loss of image quality in digital watermarking #58

Open poise0 opened 1 year ago

poise0 commented 1 year ago

I'm using Windows, tested with both openstego-0.8.6.zip, Setup-OpenStego-0.8.6.exe, and openstego-0.7.4.zip. Any cover file with transparency seems to lose its transparency after data hiding. I used a simple .txt file as the message file.

Image used: New Project(2)

Output file: output

Digital watermarking also gives error code: Image cannot be encoded with compression type BI_RGB) when using images with transparency. The image quality also decreases substantially with artifacts in the output using an opaque image, and the signature trength (via verification) is low (38%).

Image used: New Project(3)

Output watermarked file: sigoutput

I have searched previous issues for image quality but did not find an .ini file for changing image compression settings.