cgsecurity.org

An update for anyone who is following this thread. I found the website fix.video and so far 4/4 files I've uploaded (170MB-220MB) have been fixable - I had to adjust the fps to 30fps else the video was not the correct length and perhaps some may have some errors but on this small selection it's ...

Sorry for the spam - last post for tonight I promise - I looked for MP4 tags in a partial hexdump of the volume - I wonder if photorec doesn't recognise the format Nextbase use:

% egrep "mdat|ftyp|meta|stts|stsc|stsz|mfra|moof|moov|pdin" image.hex
0b557510 e9 00 00 00 1c 73 74 73 63 00 00 00 00 00 ...

Doing a hexdump on a dd of the partition

mdat is listed but I couldn't get this to be recognised as a signature in photorec:

dat 0 0x00e39bd86d646174
mp4 0 0x000000206674797061766331

Then doing an egrep on the disk image (dd) - for avc, mdat etc.
0f740000 00 00 00 20 66 74 79 70 61 76 63 31 00 ...

In case @cgrenier you wish to check the fingerprints of two files (a large and a small mp4) that do recover OK from the same SD card here goes... I wonder if some of the .mov files are sometimes missing the start or end of the file... https://share.icloud.com/photos/00dPt39fYNNGzKrpf4GRNXgxg - if ...

Digging through a hexdump (not really knowing what to look for :) - I can see the date / time of the video clips in both the readable and unreadable files which suggests they are not totally corrupted... this pattern repeats - as the time and GPS location changes.

unreadable file:

00075760 00 00 ...

OK - thank you. If in the meantime anyone else has experienced the same and found a fix / reason then I'd appreciate it. Unfortunately I wasted my money on Stellar Photo Recovery premium which has not been able to solve this either... it used the reference file method to try to rebuild the .MOV but ...

Thanks yes I saw that post but it says if " all " your files are found to be unreadable you need to join ftyp+mdat where as in my case some are readable which suggests something else is happening... would reformatting the card in the dashcam help photorec understand the sectors / boundaries ...

A previously working and regularly reformatted MicroSD card from a Nextbase Dashcam 522GW lost all files after plugging into my Mac... all that is on there now is the .VT100Spotlight folder that the Mac indexes searches with. The drive would normally have a label of NEXTBASE - this is missing ...