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.

You get a quote first, via telephone or using our online form. Once you have the quote, post the disc to the Oxford intake lab and a playable copy of the export will be sent back to you, £400 + VAT, along with your original export in the exact condition it was received in. CCTV is different from normal video. The box places the pictures into containers it created itself, indexed by channel and date/time, and then provides its own player software to view those recordings. Most of these players are only compatible with Windows. A few may only communicate with the specific model of recorder that made the disc. On a Mac, the player sits idle. At that point, the disc goes into a drawer, and the case stops moving. We use a process that is quite mundane, yet effective. Identify the container from the structure of the exported file. Move the stream of data into an open format, i.e. one format all machines can open. Leave your original export unaltered. Hash the two files to ensure integrity. Document everything that was done so another examiner could replicate the steps taken. Nothing we do will improve the quality of the video. If the system is someone else’s, we require permission from them first.

Only pay if we recover your data, 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 generate a file your PC has ever seen. A picture enters the manufacturer's own "container", the streams are marked by a private scheme, and the frames sit in time order instead of stream order. Send this to an average player and it will put them together incorrectly.

The file the recorder madeIt includes the timestamps the box created, along with the associated channel information. Re-encode and you will lose both of these, and there may also be some loss in quality along the way.

The player on the discGenerally speaking, a Windows executable is burned onto the same disc as the video. No Mac will run it, one or two will not work with any recorder but their own, and many times no viewing software was provided. This is the point where a disc will end up in a desk drawer.

What we do with it hereThe container type is determined from the file; the stream is shifted over to the new container without being re-encoded; your original is not touched; both are hashed, and the method is documented so another person could reproduce the conversion. £400 + VAT, and in most cases you only pay if we recover your data.

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 .dav or .264 at the end of it	The video is contained within a proprietary container the manufacturer never documented	Send its player along too
A disc that came with no player	Common. Then we determine the container, based on the structure within the file	Send the whole folder
An .exe file which can be used only on Windows	Cannot be used on a Mac and often cannot be used on a new PC either	Ask for a converted version
A phone clip filmed off a screen	Shot from a screen and then re-encoded, the video is no longer the evidence	Go back and request the export file
The clock inside the recorder	Clocks drift, the time is entered incorrectly on fitting day, and it is hardly ever adjusted after	Time is measured relative to a reference clock and stated as a number, never assumed

Sending it to the lab: get a quote first, by phone or using the form. Send it by tracked, insured post to the Oxford intake lab, or drop it off at the Oxford intake lab (Monday to Friday, 9am to 5:30pm, no appointment needed). The return leg is at our expense. Need help packing? Call us before sealing your box and an engineer will tell you what to pack and what to leave out. All remaining details are on our packing and posting page.

What we do, in order.

How other jobs ended →

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

A case number is assigned to your device when we receive it. An engineer then finds the real fault (free) before anything else occurs; you will be advised clearly of what will be returned and what will not, along with a single written price. Charges cannot begin until you have read this and accepted.

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

Work out what the file really is

There is little you can deduce from extensions (.dav, .264, .dat, .vid, or even an .mp4 that has had its internal structure altered). It is the structure inside that settles it. If an encrypted export does not include the password file belonging to it, there will be absolutely nothing that can open it.

Format read from the fileThe extension proves almost nothing

A copy that will play

Absolutely nothing is re-encoded. The source stream is simply placed into a standard container (with no information added or lost), and the file recorded by your device remains with us to accompany our copy back to you.

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 clock and note the gap. Most of it is caused by British Summer Time. To keep the evidence away from controversy, our reports include this gap as a numerical value, 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 look at the file list first and make a decision about what to do. We will never invoice anything until you have said yes, and in most cases you only pay if we recover your data. All of the information that we recover will be put on new media purchased by us specifically for this job, and our company pays the cost of postage back to you. 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 problem lies with the player, not the file: H.264/H.265 streams have been placed in undocumented "containers", using the makers' own stream markers, with everything ordered by time rather than by stream. When a generic decoder reads this data, it matches up frames with the incorrect neighbours and then compounds the error.
The manufacturer's proprietary viewer is not the answer: it can make changes to the visual representation of the data without telling anyone about it. If it reads data past a certain point (the disk index), the images will have no time or date information at all.
Exporting again creates a new file, not the old one: one AVI file created from an H.264 original lost some frames at the hour mark, while the metadata within the new file continued to match. Non-square pixel footage is displayed as widescreen, and every proportion in the frame changes with it.
Each redacted version is a separate, deliberately small task: where someone with no connection to the case has to be hidden from footage prior to distributing it, we blur their face and number plate during a short export. Each redacted version has its own exhibit number instead of being the master copy. Multi-camera footage by the hour is not something we take on.

What does the package contain? Your own file, unchanged; a copy of the file that can be opened by any computer; a hash for both versions; the time difference (offset) recorded as a number; either the maker's viewer software or, if none came, a description of the container the footage was delivered in; and a note of where the footage originated and all the people who have handled it since. Page one explains that this laboratory holds no forensic accreditation. Worth knowing about before spending money.

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 provided its solicitor with a disc containing four video files, a viewer that could not be installed, and an office running only Macs. We determined the type of container from the content of the files, copied the stream into a playable format, left the original export alone and hashed both. The recorder's internal clock was over thirty minutes ahead and had never been corrected after the time change, so we included this offset in our report.

Their claim concludedCourt-gradeclip

What helps, and what makes it worse.

First things to do

Request the export, not a trimmed clip
Also have the player written to the disc
Note down the recorder's make and model
Copy the entire folder across instead of just the video

What makes it worse

Re-encoding it until something plays
Filming the screen with a phone and calling that 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 this is not video in any way that your computer has previously encountered. The box put your picture inside a container of its own making and assigned unpublished identifiers to the streams within it. Therefore, your standard player has no basis upon which to begin processing it. 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 are mostly Windows .exe files, and one or two communicate only with the exact recorder that produced the disc. Get a quote first, then 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 if someone tells you they can do it, be cautious. The camera recorded the detail or it didn't; there is no way to convert those images into something that was never captured. When done correctly the copy will match the recording; when done carelessly it may drop frames or distort the geometric proportions of what was captured; therefore, we always send the original back with each copy.

Can I rely on the time stamped on the footage?

Frequently not. Many of these clocks lose accuracy over time, and many were set incorrectly on the day they were installed. Almost no one sets the clock back or forward when the clocks change. 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.

It’s still recording, and every time it loops around it takes another piece of the information you require. Pull its power now, get a quote first, either by phone or with our form, and send us the disk. Your initial assessment is free, followed by a written price, and none of this information will go anywhere else.

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Get it quoted Posting it to Oxford

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Evidence, footage and reports

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