pasqualej/dct-watermark

Automatically exported from code.google.com/p/dct-watermark

dct-watermark's Issues

DCT-Watermark.jar rev24 Seems to silently not watermark certain jpegs.

What steps will reproduce the problem?
1. download the attached file
2. run java -jar dct-watermark-rev24.jar e -d white.jpg offwhite.jpg "Hello 
Charlie"
3. examine offwhite.jpg (appears watermarked)
4. run java -jar dct-watermark-rev24 x -d offwhite.jpg 
5. an empty string is output, and error correction reports "0 bits of 96 are 
faulty" (I'm not sure that the error correction is relevant or not)

What is the expected output? What do you see instead?
I think I'd expect to see "Hello Charlie" on the output, or at least some 
indication of failure.

What version of the product are you using? On what operating system?
I'm using dct-watermark rev24, Ubuntu 12.04, linux 3.2.0-30-generic and OpenJDK 
Runtime Environment (IcedTea6 1.11.4) (6b24-1.11.4-1ubuntu0.12.04.1)
OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)



Please provide any additional information below.

Original issue reported on code.google.com by [email protected] on 25 Sep 2012 at 1:59

Attachments:

• issue.zip

need jar for video and audio watermarking by using dct

we need jar files for video dct watermarking please help us

Original issue reported on code.google.com by [email protected] on 2 Feb 2012 at 5:42

Possibly unnecessary calculations in the tool

I ported the code to C# to use it within an Open Source Cryptology learning 
tool CrypTool2. Doing so I stumbled over one calculation in the embedding 
method of the Watermark class, line 175 and 176:
        for (int y = 0; y < 128 / this.bitBoxSize * this.bitBoxSize; y++) {
            for (int x = 0; x < 128 / this.bitBoxSize * this.bitBoxSize; x++) {

From my mathematical knowledge, a/b*b is the same as (a/b)*b = a so I tested 
the same in my code, modifying it to
        for (int y = 0; y < 128; y++) {
            for (int x = 0; x < 128; x++) {
and it still works. As I'm not too familiar with the whole code and didn't 
understand every computation, I assume this is either a mistake and should be
128 / ( this.bitBoxSize * this.bitBoxSize )
or can be improved by removing the unnecessary calculation.
As it works fine for me without the calculation, I assume #2 is the case, but 
would be great if you (Or someone) could confirm.
Thanks

Original issue reported on code.google.com by [email protected] on 21 Nov 2014 at 3:22