Getting frames from a broken 3gp

[tussu]

Hi
Like many other topics here, I too deleted an important video from my phone memory card. Tried atlest a dozen different recovery programs but they all give me huge .jpg files that contain music and video data (I can open these jpg files with my mediaplayer and hear music). So, as I understand correctly that means that if I delete a file from my phone, the software deletes the file headers and the recovery program can't understand where a file ends and a new one starts. And that means, my deleted video is still out there!
I did try playing with hex editors and writing atoms, but the thing is that I don't know the exact .jpg file where my movie is "hidden". So its too time consuming to do it one by one. So I need somekind of special software that tries to extract frames out of this garbeled data. I used a program that created an exact image of my memory card, so i have now a 500 mb file with everything inside it.
Now - is there a program where I could type in the correct headers/footers (is it even possible to record another movie with my phone and use those new headers) and it tries to get still images from that 500 mb file.
Or - is it possible to find/write a program that pastes good header/footer at the 500 mb file and tries to play it. If unsucsessful, deletes the first bit of data and tries again
Thanks!

[Starman*]

I've never tried this but the common video formats start with common strings, eg my wmvs start with
"30 26 B2 75 8E" and end with "00 00 something 00". If you know the format you could try searching for the start string in a hex editor. You could copy a large section of data from that point into a new file. Depending on the results copy more or less into the new file. Will only be successful if the video is contiguous. I tried copying 1/2 a wmv with this method. It played OK but the progress indicator could not be dragged - you had to play it. I use WinHex but I'm sure it's possible with other apps. WinHex also has a file extraction utility for a drive but that is probably no better than those you tried already.

[tussu]

yesyes... thats what i was thinking. but im looking for something that automates the whole process. impossible to do it manually.

[Starman*]

You said there was one video lost in one 500Mb file. How long could it take to search for the starting string? You enter the string in the Search box (or whatever the hex editor uses) and hit the required key. Once found you copy a bunch of stuff after, save it as new file, play it and see if you need more or less data.

I could probably do the first-go extraction in the time it's taken to type this message. If you have 100 videos in the same mess that's a different matter but will not take more than a couple of hours to retrieve the lot of each is contiguous. That's all I can suggest. Perhaps others have ideas.

[tussu]

I'm back 8)
Yes, theres only one file missing but there are dozens of old and deleted ones also. And as I said in my first post, my phone deleted the file header, so there is no start string to search for.
So, after a week of searching I now have the file. Kinda...
The software has deleted the 3gp/mp4 file header and a bit of data from the start. BUT the "footer" (moov and other atoms) are intact. So I have now a chunk of data with the first part bitten off.
Now comes the problem. Headers from playable movies are exactly the same, except the length of the video data (4 bytes just before mdat, that show where the moov atom starts). How can I rewrite that part?

[Starman*]

I'm not familiar with how phones store data files. I had assumed there was a file table so that files did not have to be contiguous (to maximize memory usage). If, as you say, the header is deleted then it will be very difficult to reconstruct the mp4. If the phone just deletes the header, how does it know that the rest of the data can be overwritten? Answer not important!

My final thought is to copy the header from a complete mp4, stitch it with what you think is the bulk of the file you are interested in, and see if it plays. I've no idea if that would work. I can't help any further.