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Authored by Adrian Laskowski

Gynvael EN mission 16 - my working

Edited

I am try to solve gynvael mission 16, but finaly I am fail. I want to share my work on this mission.

First of all I download the file and decode with base64. Then I find that it is a RIFF file which is an wav file.

then I put this file into audacity and play. And sound come form my speeker 'tells' me that this is some kind of data over frequency modulation.

So I create a python scrypt to read the wav file.

Screenshot_from_2017-09-28_08-04-38

We can see the sine wave in form of discrete points. Then I convert this to square wave by set value 1 for every positive cycle of sine wave. And mesure length of pulses.

Screenshot_from_2017-09-28_08-09-12

Next set was convert this form of output to some more square wave looking.

Screenshot_from_2017-10-03_08-32-19

every 'X' is positive cycle of sine wave and ' ' was negetive sine wave cycle.

Screenshot_from_2017-10-03_08-31-44

When You compare the last above two pictures, You can see some pattern.

I assume that this is some form of synchronization before a byte is sending.

So my next step was count the pulse length and display this array

Screenshot_from_2017-10-03_08-39-04

clearly there is a pattern.

So I try to extract this pattern and display only this patterns. Next I hard workd to get only pattern, and display X when pulse length get some threshold value, and display only around 400 pulses from begining of sync signal.

AND I GOT THIS!

Screenshot_from_2017-10-04_09-54-06

Screenshot_from_2017-10-04_09-53-57

Screenshot_from_2017-10-04_07-45-17

Screenshot_from_2017-10-04_09-54-00

Clearly some kind of picture. So I try to dump this data to raw pixels, where brightnes of pixels is a length of pulses.

Screenshot_from_2017-10-04_09-54-21

This is a picture !

But there is one problem

Screenshot_from_2017-10-04_09-54-21__copy_

The length of lines differs.

And I have no idea to fix this line length issue. I give up at this time.

Below my python script.

analize_wave.py 1.96 KB
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