Investigations & evidence · deleted recorder footage
Everything turns on how much recording the machine has done since. Taking a clip out of the menu removes one row from the recorder's database, while the video blocks stay put until continuous recording works back to that region of the disk. Stop the unit early and most of the material returns with its channel and clock intact. Once new video has passed over it, none does.
Go through it with an engineer
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| The symptom | The likely cause | Start here |
|---|---|---|
| A user deleted clips from the menu or app | One database row went; the recorded blocks did not | Switch the unit off now |
| The recorder reformatted its disk after a fault | Formatting lays down a fresh index and little more | Carving handles this; the odds are fair |
| It ran on for another three days | Each further hour of recording consumes more of the oldest material | Post it without delay |
| Nothing on the disk predates the incident | Likely overwritten; the free assessment settles it | We will tell you, at no cost |
| Clips play, yet carry no names or times | Carved video keeps the pictures, loses the labels | Normal, and flagged before you pay |
| Files from an earlier attempt will not open | Streams were pulled off but never wrapped as files | We rewrap those streams into playable MP4 |
Nothing becomes chargeable until you have said yes to it. Each item takes a case number of its own the moment it arrives, an engineer establishes what has actually failed, and you are given a candid view of which files stand a realistic chance of returning. The single quote that follows is fixed, written down, and costs nothing.
The unit comes down, the disk comes out, and a write-blocked image is taken. From that point nothing more can be lost: whatever the loop spared sits on our copy.
Working on the copy, we look for the manufacturer's own tables — HIKBTREE on Hikvision, DHFS structures on Dahua. Parse enough of one and the export carries true channel names, dates and times: the form an insurer will accept.
Where no usable index remains, the image is swept from beginning to end for the start codes that open H.264 and H.265 frames, and those frames are then assembled into clips that play. Your file list states which of them kept timing information and which did not.
Nothing is billed until you have seen the recovered file list in full and told us to go ahead. What comes back arrives on new media, with the return journey at our cost, and the case stays open at this end until you have opened every file yourself.
What the loop is doing: the disk is divided into fixed-size blocks and written in sequence. At the last one the recorder returns to the first and reuses it, whatever is held there. A deleted clip survives exactly as long as it takes the writing to come round again, which is why switching off is not a precaution but the recovery itself.
Four of the five lost days were still described in the recorder's index, timestamps intact, and the fifth came back through carving as playable video with no labels. What saved it was switching the recorder off that same afternoon, after a member of staff deleted a batch of 'old clips' — one of which held a theft.
In most cases, yes. Deleting removes the recorder's catalogue entry rather than the recording, so the pictures stay where they were written until the loop reaches them. Cut the power and they stay put.
The later recording now occupies the physical space the older one held, and a hard disk keeps nothing behind it. A promise to the contrary is sales talk rather than engineering.
Frequently, provided the maker's index survives well enough to parse. Where the work falls back to carving frames from sectors, the pictures play but the labelling may not travel with them, and the file list marks which clips arrived bare.
Three things set it: how many cameras record, at what resolution, and onto how large a disk. Retention can run from a few days to several months, and the busier the site the sooner the oldest footage goes.
Loop recording is already writing over what you need, and the deadline will not move. Open a case today: the diagnosis costs nothing and stays confidential.