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in our sports club somebody stole money over and over again. So some members set up a hidden camera to record him. After the next day the money was gone and they checked the camera. The SD card worked fine in the pc and they could watch every video. They saw the thief in action. So they wanted to copy the files to the desktop. During this process the files got broken. And the pc suddenly showed that we needed to format the SD card. They say they didnt format it and left the SD card in the computer.

Now I have the SD Card and the computer. I immediately created an image of the SD card.

  • I ran testdisk, photorec and autopsy on the image and got nothing. Filesystem seems to be damaged.
  • I checked with an HexEditor and saw only zeros.
  • I created another image on another PC and its the same. Only zeros.
  • Then I checked the original SD card with testdisk, photorec, autopsy and HexEditor. Again nothing.

I dont know how the whole card can get into only zeros while copying the files from it to the PC. They could watch the movies in the PC on the SD card before. So the SD card seemed to be fine until they startet copying the files. But how can it be that not only the files got broken but also the SD card got corrupt?

Maybe someone has an idea!

More Information:

  • Created the image on an Windows PC using TestDisk. There could only be found an partition when I used "None" as the partition table type. Every other option doesnt find a partition. I dont know the filesystem type.

  • The second image I created on my Mac using

    sudo dd if=/dev/disk2 of=backup.my.sdcard.img.dd bs=512

  • The files that got broken cannot be opened by any movie software like Windows Media Player, VLC or Quicktime. But it is odd, because 2 video files (that don't show anything useful) did copy correctly and can be watched. But all other files cannot be opened. 3 broken files have only 2 metadata attributes for the resolution and fps. But they also cannot be watched.

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  • Of course very sorry for you but and your club but you will need to give much more informations regarding the system / command used for copying the file, the filesystem type, as well as what told you that the files "got corrupted"… all this could increase (in a somehow very little amount) the chances we can here be of any help. Commented Dec 17, 2023 at 11:49
  • I added more infos! Hope it helps. If you or someone else need more infos, just let me know! Thanks in advance! Commented Dec 17, 2023 at 11:56
  • Are you sure they didn't hit format? That fact that the disk images only show zeros is suspicious. Commented Dec 17, 2023 at 11:59
  • I think that if they did format it, it would show that it is in FAT32 or NTFS. But Windows shows that it is in RAW format. But I wasnt there and can only rely on what they told me. Could it be that they hit format and instantly taken the sd card out of the pc and therefore it is in RAW? Commented Dec 17, 2023 at 12:00
  • You've lost your legal trail of evidence, not to mention potentially breaking data protection law in your country. GDPR for example, is not kind to organisations setting up uncontrolled surveillance cameras Commented Dec 22, 2023 at 13:34

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I dont know how the whole card can get into only zeros while copying the files from it to the pc. They could watch the movies in the pc on the sd card before. So the SD card seemed to be fine until they startet copying the files. But how can it be that not only the files got broken but also the sd card got corrupt?

SD cards are a combination of a microcontroller, a error correction engine, and cheap, very cheap, flash memory.

The controller in the card might have just detected too many errors during reading (and that's the only time it would check so much data) and marked affected data (or much more) as unreadable and/or reset it to zero.

Whatever the exact underlying reason is: there's nothing UNIX/Linux could do for you. Your storage medium gives you zeros. That is bad luck, but no amount of cleverness in software can convert zeros back into the video.

Note that especially in the micro SD market, there's a very high chance you get counterfeit hardware, or even hardware that's been programmed to look like it has a capacity higher than what it actually has. :(

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  • Alright...too bad. Thanks a lot! Commented Dec 18, 2023 at 11:34

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