Investigations & evidence · erased recorder video
One question decides the case: how many hours has the recorder run since. Deleting through the menu drops a row from its database and leaves the video blocks exactly where they were, waiting for the loop to come round. Kill the power in time and most of it comes back with its channel and timestamp attached. Let the loop reach it and nothing does.
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| What you see | What is behind it | What to do |
|---|---|---|
| Footage was removed by hand from the recorder | The catalogue lost a line; the video did not move | Power it down at once |
| The unit wiped its own disk after an error | A format writes a new index and leaves the rest | Carving copes with this; chances are decent |
| It carried on recording for days | Every extra hour of recording eats further into the oldest video | Send the disk today |
| The oldest footage starts after the incident | Probably written over — the free check will confirm | We say so, free of charge |
| Video opens with no channel or timestamp | Carving saves the images and drops the labelling | Expected, and marked on your list |
| An earlier attempt produced files nothing plays | Raw streams were extracted but never made into files | We wrap those streams back into working MP4s |
Every item gets a case number of its own the day it lands. An engineer then works out what has actually failed and tells you plainly which files have a real chance of coming back and which do not. Only then does a price follow: one figure, fixed, in writing, and it costs you nothing to see it. Nothing is charged until you say yes.
We shut the recorder down, take the disk out and image it behind a write blocker. After that nothing further can be lost — everything the loop had not yet reached is safe on our copy.
All of this happens on the copy. The maker's own structures are what we go looking for — HIKBTREE on Hikvision, DHFS on Dahua — and where enough survives, the export carries real channel names, dates and times. That is the version a loss adjuster will take.
With nothing left to parse, the copy is read from one end to the other for the byte markers that open an H.264 or H.265 frame, and what turns up is rebuilt into clips that will play. Your file list says which of those kept their timing and which came back bare.
No invoice is raised until the full list of recovered files has sat in front of you and you have said go ahead. Your data comes back on media we buy new, posted at our expense, and the job is not closed here until every file has opened on your own machine.
How the loop actually works: the disk is carved into blocks of fixed size and filled one after another. When the last one is full the recorder goes back to the first and writes over whatever it finds. So a deleted clip lasts precisely as long as it takes the write head to return to that spot — which is why pulling the power is not a sensible precaution, it is the recovery.
A member of staff had binned what they took to be old clips, and a theft was sitting in one of them. The recorder went off that same afternoon, and that is what saved it: four of the five missing days were still listed in its index with timestamps intact, and the fifth was carved back as playable video, unlabelled.
Usually. What a delete removes is the recorder's index entry, not the video itself; the blocks holding the pictures are untouched until the loop comes back round to them. Pull the plug and they stop where they are.
The newer recording is sitting in the exact space the older one held, and a platter stores one version of a block, never two. Anyone promising to get it back regardless is selling, not engineering.
Often, if enough of the manufacturer's index is left to read. When we have to fall back on carving frames straight from the sectors, you get the pictures but the labels can be lost, and your file list says plainly which clips came back unlabelled.
It comes down to camera count, recording quality and disk size. Some sites hold a fortnight, some hold months. The more cameras there are, and the more movement in front of them, the faster the oldest recordings disappear.
Every hour the recorder runs, more of what you need is gone, and the deadline stays where it is. Book it in now: the diagnosis is free and stays confidential.