Simple script for glitching jpeg files from the command line.
- bash
- sed
- xxd
- ffmpeg (optative)
- convert (optative)
Copy the image you want to glitch into the jdump directory and run the following command:
$ ./jdump.sh YOUR_FILE.JPG
By default, the script will set random parameters and save the result in a glitch.jpg file.
If you're not pleased with the result or the file got corrupted, try again the same command as many times as you wish.
There is an important line in the script output that looks like:
+ sed s/a/3/9
In this case, a 3 and 9 are the parameters. You can specify any other parameter when running the script.
If you like the result but would like to experiment with similar changes, try replacing one of the parameters:
$ ./jdump.sh YOUR_FILE.JPG a 4 9
The first two parameters must be hex digits (lowercase) Try small numbers (1-15) for the third parameter, very small numbers can sometimes break the file
You can also specify another glitch file name:
$ ./jdump.sh YOUR_FILE.JPG a 4 9 ANOTHER_GLITCH.JPG
The script could be summarized like this:
xxd -p ORIGINAL.JPG | sed s/VALUE/REPLACE/OCURR | xxd -r -p > GLITCH.JPG
Plain hex dump of the original file wth xxd command. Replace the OCURR ocurrence of VALUE with REPLACE with sed and then perform a reverse hex dump to a new file.
You can see now why the sed arguments are so important, they look up and replace a nibble (4 bits). That's why the firsts ocurrences can break the file, they could be part of the header and contain critical information.
Other useful scripts.
Interactive glitching editor, dmenu implementation.
$ ./gmenu.sh IMAGE.JPG
Open glitch.jpg in a viewer and start playing around with parameters.
- v/b : Decrease/Increase value
- r/t : Decrease/Increase replacing value
- o/p : Decrease/Increase ocurrence
- R : Randomize!
- S : Save current parameters into file
- E : Exit
Generates a randomized gallery of 256 glitches.
$ ./gallery.sh IMAGE.JPG
Glitches are saved in a new directory and the names are formated like this: [image_number]_[VALUE][REPLACE]_[OCURRENCE].jpg
Composes a montage image from gallery.
$ ./montage.sh PATH [MONTAGE_WIDTH (def 1024) [THUMB_SIZE (def 256)]]
Creates a video from gallery.
$ ./video.sh PATH [FRAMERATE]