A recorder disk looks empty in a computer because the footage is written in an undocumented format, not as files. We image the disk, locate the video streams by structure, separate the channels and export the window you need as something that actually plays — but the recorder overwrites as it runs, so this is a job where hours matter.
$ bdr triage /dev/sdb → Device: Hikvision NVR HDD · 6 TB → Status: FOOTAGE LOOPED OVER — oldest blocks → Target: 09 Feb, 22:15–00:45 · cam 5 $ bdr engineer-working → Read-only image: taken · recorder halted in time → File system: Hikvision layout · parsed → Streams: H.265 rebuilt by timestamp $ bdr verify → ✓ channel 5 — 2h 30m recovered → ✓ exported — MP4 + timestamps → ✓ footage recovered — incident captured
DVR and NVR units record in a loop, so the moment the disk fills they begin writing over the oldest footage. Every hour a recorder stays powered is an hour of older material gone. If the footage matters, power it down and remove the disk before anything else.
The disk inside a DVR is a standard hard drive, but almost nothing else about it is standard — which is why plugging it into a PC shows an empty or unformatted volume.
Surveillance drives run continuously for years in warm cabinets, which is a harder life than a desktop disk ever has.
Surveillance drives write constantly and are frequently the cheapest component in the system. Bad sectors accumulate until the recorder stops writing or refuses to boot.
Power supply, board or firmware failure in the unit itself. The disk is usually fine, and the footage with it — the obstacle is the proprietary format, not damage.
The disk was connected to a PC, Windows offered to format it, and the offer was accepted. Recoverable, but harder, and the clock matters more.
The honest one. If the incident is older than the retention window, the material has been written over and no technique recovers it.
A factory reset or a channel wipe. Often still recoverable, because these usually clear the index rather than the video data.
The objective is not a working recorder — it is video you can actually watch and, if necessary, hand to someone else.
The disk is imaged read-only first, with bad sectors retried in short passes and skipped where they will not come back. From that image the video streams are located by structure rather than by file listing, separated by channel, and reassembled in timestamp order. Where the proprietary container cannot be read by ordinary players, frames are extracted and remuxed into a standard format — usually MP4 or AVI — so the footage plays on any machine without the manufacturer’s software.
If you need a specific window, say so at the outset. Recorder disks are large and mostly full of nothing relevant, so targeting a date and camera makes the work faster and the result easier to use.
Priced as a fixed fee rather than a range, because the work is broadly the same whichever recorder it is.
CCTV, DVR and NVR recovery is £800 +VAT flat, confirmed after a free 48-hour diagnostic. This work carries a 50% deposit up front and is one of the exceptions to no fix, no fee — because reverse-engineering an undocumented recorder format takes the same effort whether or not the footage you want survived the overwrite loop.
Send the hard drive from the recorder rather than the whole unit where you can, and tell us the make and model, the approximate date and time you need, and which camera. Full write-ups: CCTV Recovery: A SkyHawk That Warned First.
Send the device in for its free diagnostic and tell us briefly what happened; an engineer reviews it and confirms your exact quote in writing before anything starts.
Getting your data back begins with getting the device to us. Pack it up safely, pop your contact details inside, and send it over — once we’ve run the free diagnostic, we’ll confirm your exact price in writing before any work starts.
Posting it? A tracked, insured service is what we’d recommend. Rather drop it in? You’re welcome Monday to Friday, 9am to 5:30pm — just package the device up as above first.
Want a bit more detail first? Fill in the form with more about your issue and an engineer will review it and send you a custom quote.
We’ll be in touch shortly. If it’s urgent, call 01865 593000.
The things people ask us most before sending a recorder or card in.
Usually. DVR and NVR units write to ordinary hard drives but in proprietary, undocumented formats, so the disk is imaged read-only and the video carved out by structure rather than read as files. Where the recorder itself has died, the disk and its footage are generally untouched.
Recorders loop continuously, so the oldest footage is overwritten once the disk fills — often within days or a few weeks depending on camera count, resolution and frame rate. If footage matters, take the disk out of service immediately; every hour of continued recording costs more of it.
No. Windows cannot read the proprietary format and assumes the disk is blank, which is exactly why so many recorder disks arrive already initialised. Decline the prompt and disconnect it.
Yes, and telling us in advance helps considerably. Timestamps are embedded in the video structure rather than in file metadata, so a specific window can be targeted — which makes the work faster and the result far easier to use than a bulk export.
Something that plays without the manufacturer’s software — frames are extracted from the proprietary container and remuxed into a standard format, usually MP4 or AVI, so it opens on any machine and can be shared with insurers or police.
£800 plus VAT flat, confirmed after a free 48-hour diagnostic. This work takes a 50% deposit up front and is an exception to no fix, no fee, because the reverse-engineering effort is the same whether or not the footage survived the overwrite loop.
A free diagnostic, footage recovered by camera and time from a DVR, NVR or SD card — even a failed recorder — and exported as standard files for your insurer or the police. Get in touch.