RDR / Evidence and expert work / Export files, their containers and players

Video exhibits · getting the file to open in the first place

CCTV discs that will not play, Reading. The disc turned up and nothing you own will open it.

Post it here and a version that plays comes back, £400 + VAT, with your export returned in the state it arrived. CCTV is not ordinary video. The box wraps each picture inside a container it invented, indexes the lot by channel and time, then ships a viewer of its own to read it back. Those viewers are usually Windows-only; a few will speak to nothing but the model that made the disc; on a Mac they sit there doing nothing. That is the point at which a disc goes into a drawer and a case stops moving. What we do about it is dull, and it works: identify the container from the structure of the file, move the stream into a format every machine opens, leave your original alone, hash the pair, and record exactly what was done so a second examiner can repeat it. None of that improves the footage. If the system is somebody else's, we need their authority first.

No files back, no fee — on most jobs Logged as an exhibit from the start The loop is recording over it now

Talk it through in confidence
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Why no player will touch it.

This is not everyday videoA recorder does not produce a file your computer has ever seen. Picture goes into the manufacturer's own container, stream markers follow a private scheme, and frames sit in time order rather than stream order. Feed that to a general player and it assembles them wrongly.

The file the recorder madeInside it are the timestamps the box wrote and the channel information beside them. Re-encode and you lose both, plus a little quality on the way out.

The player on the discUsually a Windows executable burned alongside the video. Macs will not run it, one or two refuse to work with any recorder but their own, and very often no viewer was supplied at all. Which is the moment a disc ends up in a drawer.

What we do with it hereThe container is identified from the file, the stream moved across without re-encoding, your original untouched, both hashed, and the method written down so somebody else can repeat the conversion. £400 + VAT, and on most jobs no fee if nothing comes back.

Format, player and clock, in that order.

Not here? Tell us what it is doing →

What you're looking at	What is likely wrong	What happens next
A file with a .dav or .264 ending	Video wrapped in a proprietary container the manufacturer never documented	Send its player along too
A disc that came with no player	Common. We then identify the container from the file's structure	Send the whole folder
An .exe that will only run on Windows	No use on a Mac, and often no use on a recent PC either	Ask for a converted version
A phone clip filmed off a screen	Filmed off a monitor and re-encoded, it stops being the exhibit	Go back and request the export file
The clock inside the recorder	Clocks drift, get typed in wrong on fitting day, and are rarely touched again	Measured against a reference clock and stated as a figure, never assumed

Getting it to the lab: the lab takes parcels by tracked, insured post, and the return leg is at our expense. Unsure how to pack it? Ring before the box is sealed and an engineer will tell you what to send and what to leave out. The rest of the detail sits on the packing and postage page.

What we do, in order.

How other jobs ended →

Logged the day it lands, and the look costs nothing Free

A case number goes on your device the day it reaches us, and an engineer then finds the real fault — free, and before anything else happens. You are told plainly what will come back and what will not, with one fixed figure in writing beside it. Nothing chargeable starts until you have read that and said yes.

The look costs you nothingA fixed price, in writingStill nothing to pay

Work out what the file really is

You can tell very little from an extension — .dav, .264, .dat, .vid, even an .mp4 whose internals have been rearranged. What settles it is the structure inside. An encrypted export needs the password file that belongs with it; short of that, nothing opens at all.

Format read from the fileThe extension proves almost nothing

A copy that will play

Nothing is re-encoded. The stream is moved into a standard container exactly as it stands — no data added, none discarded — and the original file your recorder wrote stays with us to travel home alongside the copy.

Stream copied over, not re-encodedThe original stays as it is

The clock is measured, never assumed

We set the recorder's time against a reference and note the gap. British Summer Time causes most of it. Whatever the gap comes to goes into the report as a figure, which spares everyone an argument in front of a tribunal.

Set against a reference clockRecorded as a figure, not guessed

The list first, then the bill, then the files

You see the file list first, then decide. Nothing is invoiced until you have said yes, and on most jobs there is no fee at all if the data does not come back. What we pull off goes onto media bought in for your job, and the postage home is ours. The case stays open on the bench until you tell us the files open on your own machine.

Nothing billed until you say yesNew media, bought for the jobPostage home is on us

What we keep finding on recorders

The fault is in the player, not the file — H.264 and H.265 sit inside undocumented containers, with stream markers of the maker's own devising and everything ordered by time rather than by stream. Point a general decoder at that and it matches frames to the wrong neighbours, then compounds the error.
The manufacturer's viewer is not the answer — it can alter what you see without saying so, and once it starts reading beyond the disk index you get pictures with no date or time on them at all.
Re-exporting produces a new file, not the old one — one AVI made from an H.264 original lost frames at an hour boundary while its metadata carried on matching. Non-square pixels get displayed as widescreen, and every proportion in the frame shifts with them.
Redaction is a separate, deliberately small job — when people with no connection to the matter must be hidden before a clip goes out, faces and plates are blurred over a short export, and the masked version leaves under an exhibit number of its own rather than as the master. Multi-camera material by the hour is not something we take on.

What the parcel contains: your own file, untouched; a second version any machine opens; a hash against each of them; the clock offset written as a figure; the maker's viewer, or a description of the container where no viewer came; and a note recording where the footage originated and everybody who has touched it since. Page one states that this laboratory holds no forensic accreditation — worth having in front of you before you spend anything.

How one of these actually went.

PL · RDG-2026-2022ON FILE ✓

A licensing hearing in a fortnight, and a disc nobody could open

Two weeks before a licensing hearing, a bar off Broad Street sent its solicitor a disc: four video files, a viewer that refused to install, and an office running nothing but Macs. We identified the container from the files themselves, moved the stream into a format that plays, left the original export alone and hashed both. That recorder's clock was running more than thirty minutes ahead and had never been put back at the seasonal change, so the offset went into the report.

Their claim concludedCourt-gradeclip

What helps, and what makes it worse.

First things to do

Request the export, not a trimmed clip
Have the player written to the disc as well
Note down the recorder's make and model
Copy the whole folder across, not just the video

What makes it worse

Re-encoding it until something plays
Pointing a phone at the monitor and calling it the file
Renaming the files to look tidier
Expecting conversion to sharpen the image

What people ask before they send it.

Why will nothing on my computer open this disc?

Because it is not video in any form your machine has met. The box wrapped the picture inside a container of its own devising and marked the streams to a scheme it never published, so a general player has nothing to work from. There is usually nothing wrong with what you were given. The program being pointed at it is the wrong program.

I double-clicked the viewer on a Mac and nothing happened.

Expected. These viewers are almost all Windows executables, and one or two will talk to nothing but the exact recorder that produced the disc. Post it to us and you get something any computer opens, alongside your export in the condition it reached us.

Will converting it sharpen the picture?

No, and anyone promising that should worry you. A camera either captured the detail or it did not, and no conversion invents it later. Done properly, the copy matches the recording. Done carelessly it drops frames or stretches the geometry, which is why your original always travels back beside it.

Can I rely on the time stamped on the footage?

Frequently not. These clocks drift, plenty are wrong from the day of installation, and almost nobody adjusts them in spring or autumn. We set the recorder's time against a reference and record the gap as a number, so nobody has to guess at it afterwards.

If this sounds like yours, start here.

Video the recorder kept → Clips off a dashcam or bodycam → What goes in the report → Casework for court and claims →

Stop the loop before it reaches your clip.

The recorder is still writing, and each time it comes round it takes more of what you need. Pull its power now, then get it to us. The first look costs nothing, a fixed figure follows in writing, and nothing you tell us goes anywhere else.

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