Max patch to destroy JPEG data

hi

for a bit of fun with computerviruses i once used the filein object.
you can read in a file, then scramble/do whatever, then you would have to write it out again and then read back as jpg.

hth
hans

Hi Hans

filein looks fairly promising, for some reason it didn't autocomplete when I created the new object, so i must have missed it! There doesn't seem to be a complimentary fileout object though, i'm stuck as to the best way to use this. Looks like I could fairly easily write a scrambling type of patch if i could replace data immediately after in the file after reading that part.

collect your scrambling in a text object and write it out, specifying a path and a filename ending with .jpg.
then you can read back in from there as an image in e.g. jitter.
just make sure, you don´t scramble the files header, else it won´t be possible to pass as a .jpg anymore.

and don´t forget to post your patch, when you are finished :-)
hth
hans

Heh, yeh i figured i probably didnt want to scamble the header or the palette, im just interested in doing the image itself.

Hi there, I have been trying to figure a way to automate this process of destroying the jpeg data. the_man, how far did you get with this patch? I'm struggling with the filein object, specifically with Max crashing as I write as a text object and also with specifying the path and filename. I did find a fileout object that somebody had written though.

In case you have Jitter, it is far more straightforward than with max objects alone to import (importmovie) process and export (exportimage) various image formats including jpeg with jit.matrix.

I'm also trying to achieve this effect in an 'analog' way (get the bytes in using filein, modify the bytes randomly then export). I have managed to import the image using the filein + text object but when I try to dump the whole thing in the fileout (no bytes were harmed at this point), I only get a 4KB image instead of 34KB... Does anyone have a theory on this ?

thanks,
Nicolas

i checked your approach. same problem. maybe max can't pass such a big message at once or fileout can't take it.
i must say i was expecting that fileout can handle single bytes and write them. it's not really the complement of filein.

Hello folks,

Cool to see people using the fileout, uncool to see it doesn't work as expected. I checked and indeed, when exporting you're left with a 4096 bytes file. I must admit i actually have no idea why or how this is possible. My guess is this limit is imposed at either the list message (a limit of no more than 4096 ints/bytes?) or some issue within Java.

I'll check if i can rewrite the fileout so it won't require a list for input but instead have int's stored in an internal array. Maybe that will help? Any help/suggestions are welcome...

Thanks,
FRid

(Funny sidenote, i actually wrote the object partly because of this post)