Split binary file every occurrence of a group of characters
Hello I am new to scripts, codes, bash, terminal, etc.
I apologize this my be very scattered because I frankly don't have any idea where to begin and I have had trouble sleeping lately.
I have several 2GB files I wish to split.
This Code
reoccurs several times in each file, sadly they are not evenly spaced otherwise
Code:
split -a 6 -b 2k
would work just fine for what I am doing.
Out of the first 12 bits 5,6,7,8,9,10,11,12 are random, they change in sequential order and they must be included at the start of the file.
The files should start at
Code:
00 00 01 BA etc
and end before the next occurrence of
Code:
00 00 01 BA etc
Code:
00 00 01 BA
Occurs every 2048 bits but is not the part I'm looking for.
Just the bits after the first 12 are important.
I have been searching for a code to split the file at every occurrence. After trying and failing with many different tricks around the internet, I have decide to ask for help.
Back Story to problem:
I have a 500GB HD that had a 40GB HFS+ partition that I was using to transfer files from an old Dell PC to my Mac. Well, I needed to reformat it I no longer remember why.
Well, somehow the partition map got messed up and instead formatted the HFS 450GB partition. Which had all my home videos on it.
I just got the disks to burn them all to DVD to save in a lock box. 20 Years of video.
I found an application called disk drill and used that to recover all the data.
I am not sure if everything was found but it seems like it may have reconstructed the important stuff.
My problem with resolution:
Well, the videos are all jumbled up, bits and pieces of Mpeg2 videos are mixed together.
I figured out where the files need to be split with the help of an app called HEX Fiend.
And turns out there is a type of timecode used in the mpeg 2 files binary data. So using that I was able to correct 2 video files. Took me a week.
Last edited by PatrickE; 03-29-2013 at 05:55 PM..
Reason: I realized I repeated things unnecessarily.
So the asterisks can be any hex digit. The bytes in blue must match exactly. What about the first four bytes in your sequences (highlighted in red)? Do they need to match exactly or can they be anything as well?
Also, what happens with this entire sequence when the file is split? Is it discarded and not included in either file? If not, on which side of the split should it appear? Should the matching bytes be placed at the end of one file or the beginning of the next?
Might there be more than one occurrence of this sequence in a file, requiring that a single file be split into more than 2 files?
Do you have any preference with regard to the new file names, e.g. movie.mpeg might be split into movie.mpeg.1 movie.mpeg.2?
Correct the asterisks can be any hex digit, The Blue must be exact. The red thats hard to say they also never change.
---------- Post updated at 04:01 PM ---------- Previous update was at 04:00 PM ----------
The Matching bits need to be at the beginning of the files.
---------- Post updated at 04:04 PM ---------- Previous update was at 04:01 PM ----------
Ah Yes there are several hundred occurrences and each needs to be in a separate file. As for filename I would like it to include the original filename. Wait no the filename can be anything it don't even have to be in order thats a different project. LOL Sorry
---------- Post updated at 04:10 PM ---------- Previous update was at 04:04 PM ----------
Okay after the files are split I would use
Code:
for i in *; do mv "$i" "$( xxd -ps -l 55 "$i")"$i; done
to add the start hex code to the filename and then "better finder rename" to remove the parts of the hex that are unnecessary to sorting the files.
Original File name Movie.mpg
After that I would have 01c0-0e17-44E2DD28FC010189-Movie.mpg
Those first 8 digits help me sort the correct files into folder's.
Example there will turn out to be about 4 separate files sometime's more that was mixed into one video.
The remaining digits put the video file back in order.
After thats done each folder would contain all the correct pieces of each of the video file's in order.
I then CD to that folder and
So, you need to split the file based on 00 00 01 BA ** ** ** ** ** ** ** ** C3 F8 00 00 01 BB 00 12 80 C4 E1 00 E1 7F B9 E0 E8 B8 C0 20 where the first 4 pair of hex digits may or mat not be the same, the next 8 pair (i.e. *) can b anything and the remaining should match, right?
--ahamed
---------- Post updated at 03:52 PM ---------- Previous update was at 03:49 PM ----------
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