Why Do You Need a Video Forensic Tool?
As is the case with every phase and element of digital transformation, video forensics brings with it many challenges. At this point, video forensic tools are designed to keep these challenges in mind so that they address and mitigate them as far as possible.
Forensic Video identification
One of the responsibilities of digital forensic investigators in video forensics is forensic video identification. This entails comparing images from a database to digital evidence gathered or acquired. The problem investigators face here is twofold.
- There might not be an ample number and range of prior samples available to compare the digital evidence to.
- More importantly, since the evidence might be sketches or IR images, it might be difficult to heterogeneously link them to the digital images in databases.
Additionally, human factors such as aging, the appearance of marks or scars, etc can also interfere with the facial recognition system. Newer forensic tools are addressing such issues, but forensic investigators have a larger part to play here in choosing the right tool as per their needs.
Ability to distinguish
Another challenge in Video Forensics is recognizing the difference between simple image enhancements and altogether doctored images. The only true distinction arises from the intention of the person editing the content, which, as expected, cannot always be gauged.
Video forensic tools play their role here and speculations about whether the ‘enhancements’ were made with an intent to deceive the viewer can be put to rest.
There is oftentimes a legal burden on forensic video analysts to distinguish between organic digital videography and that containing computer-generated imagery. This first requires the analyst to determine the source of the imagery to ascertain if it originated from a camera in the first place.
Subsequently, source camera identification techniques in video forensic tools can be executed to determine the imagery’s authenticity.
Enhancement and storage
The most common sources of video evidence are CCTV or mobile phone cameras. These, intuitively, are not the most high-quality video-recording devices. This hampers the already complex job of forensic analysis even more as small details – sometimes the make-or-break points of a case – might not be discernible.
Video forensic tools usually come with a built-in feature of video enhancement to address this challenge. In this manner, they allow for low-resolution content to be rescaled to whatever degree possible.
Storage of video files acquired in evidence can prove to be a menace due to their overwhelming number and respective file sizes in some cases.
- Video compression is one solution to deal with this issue but there are obvious caveats involved. For instance, while compression provides for efficient use of limited space, it expectedly leads to loss of video quality, rendering the evidence unrecoverable and unusable in extreme instances.
- This can lead to restricting the ability of forensic investigators to perform effective analysis.
Luckily, newer video forensic tools come equipped with newer and often better storage solutions to mitigate the effects of this shortcoming.
Adaptation to developments
The digital forensics niche is an ever-evolving one, with newer case cracking means requirements and corresponding upgrades arising every now and then. New technology such as cryptocurrency, metaverse, Internet of Things, ‘smart’ devices, etc is powering and accelerating the fourth industrial revolution.
Digital forensics, therefore, needs to adapt to these changes and develop advanced solutions that cater to how we experience the world around us. While in video forensics, video forensic tools are one such development with AI & Big Data integration, they are enhancing law enforcement departments.
Benefits of Employing Video Forensic Tool
We will now discuss some of the most important actions that video forensic tools are used to perform.
We will now discuss some of the most important actions that video forensic tools are used to perform.
Video Storage and Processing
Acquisition and storage are some of the first steps in any evidence analysis procedure. A large amount of data needs to be effectively stored in a manner that enables them to be later retrieved with ease.
- Video enhancement activities are then carried out by forensic video analysts such as brightness, contrast, and gamma adjustments. Additionally, noise reduction, frame splicing, and filter additions are performed.
- Video playback speeds might also be adjusted as per requirement.
Once video evidence is analyzed, forensic reports can also be generated to be handed over to law enforcement agencies. Such reports contain information about the steps taken and the obtained outcomes of the investigation performed.
Import and file type conversion
As discussed earlier, most digital video evidence is captured on CCTV or mobile phone cameras. Due to a large number of types of such devices, the resulting video file types are also diverse. Consequently, video forensic tools are required to have capabilities related to both import and conversion of such a wide variety of file types.
Conversion of digital surveillance video files from their original formats into those that are accessible and readable by the video forensic tool in question is one of the capabilities that they come equipped with.
Forgery detection
It might be surprising to know how many times forged video evidence is submitted in a court of law. This makes the job of digital forensic investigators even more crucial – with added difficulty, of course.
Forgeries in images and videos are exposed in much the same way that the source camera device is identified. Camera response functions, this time taking the form of digital X-rays, are mapped and those taken from different parts of an image or video are compared to each other to look for inconsistencies.
Furthermore, if the source camera or a handful of unspoiled images taken by it are available, another method is employed. Whilst the first method compares different parts of one image, the second method compares the photo-response of similar but separate images to deduce whether the sample was forged.
Further still, it is important to distinguish between a copy of a video and one that is only similar to the ‘original’ but not a copy. Such a case may arise, for instance, when multiple devices are used by bystanders to record the same scene. This furthers the need for source camera identification techniques that digital forensic tools come equipped with.
Tamper detection
Generally, video tampering detection relies on the analysis of an assortment of factors. These include detection of cloned regions within any part of the video, frame or scene inconsistencies, discrepancies in the chain of custody, and even as far as structural and administrative irregularities which might hint towards targeted attacks.
Video forensic tools employ statistical analysis, complex mathematics, and algorithms to determine whether a video or a portion of it, was tampered with. The detail that these computations can capture is truly marvelous; even a frame containing a duplicated region from another can be pointed out. This is also made easier by the fact that two different frames will rarely have the exact same lighting conditions visible to the camera lens. This makes it that much more difficult to superimpose a part of one frame onto another without giving the tamper away.
Hidden Content Recovery
The phenomenon of steganography has taken momentum in the past few years. Similar to cryptography, steganography delivers secret information. The difference between the two is subtle but important. The former scrambles information and only the entity with the correct access key can “unlock” it. The latter is more often encountered in digital forensics as it is the practice of hiding a secret in plain sight. In simple words, steganography is used to camouflage information within seemingly innocent content.
Forensic analysis of such content is important firstly to separate the “innocent” content from that which in fact contains malicious steganographic content. Subsequently, the content that falls under the second umbrella can be brushed through and the original content recovered before being presented as evidence in legal proceedings.
