The purpose of having a DVR system in place is to ensure a higher level of security. In case of an incident or criminal activity, the video footage can be retrieved and examined to come to the bottom of what truly happened and bring the ones responsible to justice.
However, it’s more than common to encounter problematic DVR video footages when conduct video forensics.
Worse still, the DVR data recovery process is far from simple, especially if you’re dealing with mis-formatted, overwritten, or deleted files. Sometimes, there is nothing malicious about deleting old footage. In fact, DVR systems “incidentally” delete them automatically to make room for new footage to be saved.
Nevertheless, you’re going to need to be equipped with the right knowledge if you want to bring it back.
Today, we will discuss the reasons why data loss in DVR units can occur, give you guidelines on the most recommended route to take, and answers questions like what to do if you don’t have a backup at hand and what DVR data recovery procedure works best.
Data loss in DVR units can occur due to multiple reasons
Before we move on to DVR data recovery more in-depth, a few words on why data loss in DVR units can occur. Next to each, we’ll also list the recommended course of action to take in each of these scenarios.
Water damage
Even though your first instinct may tell you to dry the DVR unit due to it having come into contact with water, DO NOT dry it!
Attempting to do so would accomplish nothing but subject it to further damage, which can greatly reduce your chances of successful HDD data recovery.
The solution, although not ideal, is to actually keep the hard drive wet.
Fire damage
If the DVR unit gets damaged by fire, one of the key points to remember is to avoid trying to take it apart without professional assistance, else you might cause irreversible data loss.
Although it’s possible to salvage it, this requires specialized data recovery equipment.
Accidental deletion
Out of everything, data loss due to accidental deletion is arguably one of the most salvageable causes of data loss. Upon normal deletion, the data itself doesn’t get erased, merely “unlinked” from the data structure, so the operating system no longer recognizes the data is actually written on it.
It will easily help you recover these files even if they have been misformatted, deleted, or overwritten.
A common reason data might corrupt is when detaching the SD card too soon when copying data from or to it so it doesn’t get a chance to be saved properly.
Of course, someone might even decide to format an SD card, either due to the need to make more space or as an attempt to conceal crucial evidence.
In both of these cases, SVR for HikVision can help you restore the data that’s on it.
Malware
Malware is one of the most potent cyber security threats that can do all sorts of things:
Install a backdoor
Steal data
Delete data
Encrypt data
Cause performance issues
Monitor your actions
etc.
Some nefarious forms of malware are so potent in their design that they either destroy your data on purpose or make it inaccessible. Although most DVR units are running their own operating systems (usually a Linux distro), malware can theoretically still be a potential cause of data loss.
Hardware failure
Sometimes, a DVR unit can start failing due to physical damage or wear and tear. In case you hear any strange-sounding noises coming from the unit, this is usually a sign that it’s going to need professional repairs.
Trying to repair it on your own is NOT recommended, as this introduces an unnecessary risk of permanent data loss.
Bad sectors
In layman’s terms, a bad sector is a part of the hard drive that has been permanently damaged. If you suspect you’re dealing with bad sectors, it’s essential to use a professional computer data recovery software such as DRS by SalvationDATA.
It comes with built-in scan modes that will detect whether there are any bad sectors on the drive. With the help of disk imaging, it will help you recover the data affected. Plus, It supports a wide range of hard drive brands.
DRS comes with several disk diagnostics, file recovery, file carving, disk imaging, and firmware recovery features.
DVR units automatically delete old recordings to make room for more
The problem with DVR data storage is that it comes in a limited quantity. In other words, when the hard drive gets full, the unit has no other choice but to overwrite some of the old footage to make room for the new one.
A typical DVR unit has enough space to store recorded footage for 15-30 days.
That’s the bad news.
The good news is there is a chance you can recover the data with HDD recovery tools such as SVR for HikVision. These will help you recover any data that was overwritten by HDD space constraints. However, you should know that the chances of successful recovery decrease with each passing second.
A hard drive only has a finite amount of storage space available.
After a file has been deleted, every passing seconds reduces the chances of successful recovery
To expand on the issue of overwriting old footage as the device runs out of space, know that you may be out of luck if you wait too long.
By doing so, chances are that the space occupied by the recording has only been marked as empty by the operating system to store other data onto, but not physically deleted.
However, if you wait too long, it’s only a matter of time before other data will be written over it (since it has been marked as “available to be written to”). As you can imagine, this will make the process of DVR data recovery much more complicated, if not impossible (and even if successful, bits and pieces of video might be missing after restoration).
If you want to maximize your chances of successful DVR data recovery, you must be quick to act!
Recovering from backup is ideal... but it's not always an option
If you have a backup available, DVR data recovery is a piece of cake. In fact, it’s as simple as inserting the storage medium and copying the files, just as if you were to do a regular transfer from a flash drive, SD card, or an external drive to your computer.
Unfortunately, having a backup at hand is not always the case. Often, making regular backups is extra work the DVR unit’s administrator is either not willing to do or doesn’t know how to approach.
Therefore, you shouldn’t count on having this option available.
Is it possible to recover overwritten and deleted CCTV files?
Long story short: with the right software and circumstances, yes. This is likely to be the case even if the disk has been damaged in the process.
For a better understanding of how the DVR data recovery process works, let’s dive in a little deeper.
Without making it too technical, the process is slightly different compared to how regular computers write data to the hard drive.
For this example, let’s imagine we’re dealing with a 24fps CCTV camera. The term simply means “frames per second”, which means that the camera will write 24 frames per second to the HDD.
A typical CCTV also formats data in a different way than a Windows PC. In some cases, you will need professional video forensics tools like VIP 2.0 to convert the footage recorded to another format in a forensically sound manner.
For best results, you must follow the right procedure
To give you a brief step-by-step summary, the procedure is as follows:
STEP 1: Disconnect the unit
STEP 2: Remove the screws
STEP 3: Remove the cover plate
STEP 4: Locate the hard drive and disconnect it
STEP 5: Connect the extracted hard drive to the computer
STEP 6: Recover the data by using a professional hard drive data recovery software
SVR for HikVision makes the process of data recovery fast and easy with just a few clicks.
Can you recover deleted data from DVR units by using nothing but the commandline?
Technically, yes, but it won’t be easy. This is particularly true if you don’t consider yourself tech-savvy.
Furthermore, there are certain limitations to what the CMD data recovery approach can accomplish.
If you’re not 100% sure what you’re doing, your actions could even cause permanent data loss.
Recovering lost data through a command-line interface is possible, but it won’t be easy.
A professional DVR recovery software makes all the difference
For those digital forensics or law enforcement professionals who want to ensure the best chances of success with DVR data recovery, working with the right industry tools is a must.
SalvationDATA developed SVR for HikVision to give anyone with even the most basic computer knowledge a simple way to recover deleted and overwritten CCTV video files. It allows you to get the job done in a forensically sound way at the click of a button.
Among its features, you’ll find:
One-click DVR data recovery (works for deleted, overwritten, and misformatted files)
Works with most HikVision DVR and NVR systems
A built-in video player for fast video preview
Timestamp correction
Bypasses the password
The option to scan specific sectors
Easy search that allows you to filter the results by start date, file name, channel id, file size, first image, and more!
Did all of this get you excited and ready to give it a try?
Thanks to modern digital forensics tools like SVR for HikVision, you can now solve more cases with laser-sharp accuracy even if you’re not tech-savvy.
Conclusion
DVR data recovery is no walk in the park, but with the right data recovery equipment and software, it can be done.
By reading this guide, you’re now equipped with the knowledge of how to proceed in these kinds of situations as well as what to avoid if you want to maximize the chances of successful recovery.
