What relation between 10 digits and datetime-CodePudding

I search the relation between these times (in seconds) and these timestamps

30 seconds => 1189765120
1 minute => 1198153728
2 minutes => 1206542524
4 minutes => 1214930944

These info come from "Image Line FL Studio" music software.

I try to make a program in Python to manipulate FLP file, and I search without success the function for example: F(30) = 1189765120

CodePudding user response：

Ok, this time I found the answer (the exponential progression 1/2, 1, 2, 4 minutes of your length, and the counting bits, and the 0 almost always gave me the hint: it looks like floating point representation)

#include <stdio.h>
#include <stdint.h>

int main(){
    uint32_t l[]={1189765120, 1198153728, 1206542524, 1214930944};
    for(int i=0; i<4; i  ){
        printf("%f\n", *(float *)(l i));
    }
}

gives

30000.000000
60000.000000
120001.468750
240000.000000

So, what you have here, is just float32 representation of time in milliseconds. The information was there after all, and it was indeed a timestamp. With an extra milliseconds and some micro and nanoseconds in the 3rd case to make the reverse engineering harder.

Edit: Since it is flagged python (tho it was more a math puzzle than a coding question) here is how you can do it in python (handling bits is more natural in C, but there is a package in python to do so)

import struct
l=[1189765120, 1198153728, 1206542524, 1214930944]
for x in l:
    print(x, '=>', struct.unpack('f', struct.pack('I', x))[0])

2nd Edit: and only now I realize that your question was for F(30)=1189765120, not the other way round (I was too focused on the puzzle), well, it is just the reverse

import struct
def F(sec):
    return struct.unpack('I', struct.pack('f', sec*1000))[0]

>>> F(30), F(60), F(120), F(240)
(1189765120, 1198153728, 1206542336, 1214930944)

Note the slight difference for F(120) from the number you gave. Explained by the extra microseconds