What Can We Deduce From Audio & Video Forensics?

1. The legitimacy of the footage

A vital part of video forensics is to conduct the analysis of video evidence to ensure it’s legitimate. Forensic video analysis in particular requires the expertise of a trained forensic video analyst to double-check that no one has tampered with it or altered it in any way, shape, or form.

The audio elements

Don’t forget that the audio elements are an equally important part of the audio and video forensics process. If, for example, there is a sudden change in the sound, this could indicate that either the environment has suddenly changed or that someone artificially tried to glue the pieces together. To either confirm or deny these suspicions, forensic analysis of voice recordings will also take a look at whether the person in the recording has a consistent tone and volume of voice.

The video elements

In a similar vein, the digital video forensics process aims to establish the integrity of the video footage by checking whether the lightning and shadows, for instance, are consistent throughout the recording. After all, a forensic videographer may be tasked with using these subtle clues to confirm the time and place the recording was made. In case any of the transition look unnatural, this could be a sign of malicious tampering with the video evidence, which becomes apparent when we slow the footage down to examine it frame-by-frame.

2. The identity of the people on the recordings

What modern technology can accomplish borders on surreal. Using facial recognition in digital forensics, we can scan the exact proportions of an individual’s face to determine their identity. The basic premise is to compare the scanned readings with the ones recorded in the database. If there’s a match, we can determine the individual’s identity with a high percentage of reliability.

The very same technology can be used to compare objects too

Computer forensic analysis of an object can be made whenever there’s a need to compare two objects – the one secured at the crime scene or confiscated from the suspect with the one recorded by a CCTV surveillance system. Once again, the technology makes a virtual ‘skeleton’ of the object and tries to see if the scan of another object’s proportions triggers a match. Bear in mind this area of digital video forensics is relatively young, so we can expect new interesting developments as time takes its course.

3. Moving object information and parameters

Nowadays, digital technology is part of our everyday lives whether we like it or not. At every corner and intersection, there is some kind of a surveillance system put in place that records its surroundings 24/7. This allows image and video forensics specialists a glimpse into what really happened at the crime scene without necessarily having to rely on a witness’ testimony.

To list a couple of practical examples, you can expect a CCTV unit at:

• Traffic intersections
• Parking lots
• Convenience stores
• Major retailers
• Banks
• Restaurants

All of that doesn’t even take into account the fact that almost everyone carries around a smartphone with a high-definition built-in camera to record something on demand, thus increasing the chance of there being a recorded footage of the incident, should one take place.

There’s one of these around every corner.

A practical scenario that showcases the power of modern forensic audio and video analysis technology

How is this relevant to object identification, you may ask?

Simple! Let’s imagine a rather common scenario in which a vehicle crashes into another vehicle at the parking lot and then races away in an attempt to flee the site of the accident, a chain of events that’s otherwise known as a hit and run incident.

Even if the device that recorded the incident isn’t connected to any special audio video forensics technology, the recording itself may be enough in the right circumstances. Later on, the very same footage can be imported to advanced video forensics tools such as SalvationDATA’s VIP 2.0 to get an accurate read of the vehicle’s:

• License plate numbers
• Direction
• Speed
• etc.

By using advanced digital forensic video enhancement techniques, getting the exact license plate numbers down is more than possible. This is doable even if it was filmed in unfavorable circumstances such as during the night or in the midst of a heavy downpour, which is one of the several challenges law enforcement has to deal with on a daily basis when analyzing video footage.

These techniques include:

• Masking
• Interlacing
• Demultiplexing
• Sharpening
• Video stabilization

Then, the only thing that’s left for a forensic video analyst to do is to connect to a vehicle registration database and we have uncovered our suspect! Not only that; based on the direction and speed of the vehicle, VIP 2.0 can calculate the most likely route the driver has taken so the vehicle can be tracked down as the local law enforcement troops are put on alert.

4. Whether a crime has taken place

Before video footage can be considered admissible as evidence in the court of law, proving its legitimacy is only the first step. Analysis of video evidence must also determine:

• Whether a crime has taken place
• What kind of crime has been committed
• The identity of the suspect
• Its legitimacy

Only by making sure the video evidence presented ticks all the boxes can it be considered up to the legal system’s standards. Of course, this is often much harder than it sounds…

Analyzing the video footage comes with several challenges

In practice, the filming circumstances may not always be ideal, and a DVR examiner is essentially forced to work with the video footage that’s available. The challenges when working with video evidence may come in the form of:

• Excess sunlight and glare
• Pitch-black darkness
• Shaking of the recording device
• A muddy or stained recording lens
• Heavy rain
• etc.

Blurry and low-quality footage can be a problem and is sometimes an unfortunate reality in this line of work.

All of the above introduces the need for video enhancement techniques to salvage the video footage and improve its quality without inadvertently making it inadmissible in court. To name an example, using AI for the purposes of forensic video enhancement is not a good idea, because the opposing legal investigation can make the legitimacy of the evidence presented come under question and thus rule it out.

Furthermore, there’s the ever-present problem of having to deal with files that are fragmented, deleted, or overwritten. Without industry-grade tools like SVR for HikVision, extracting them successfully would be nearly impossible, but nowadays, it can be done with just a few clicks. Another obstacle is that sometimes, CCTV units are protected by a password, which SVR also helps you bypass without issues. Have you downloaded your free trial yet?

5. The exact date, time, and location of the crime

If you’ve ever viewed any kind of security footage, you’ll know that CCTV systems tend to imprint a timestamp on the footage recorded. Upon review, this makes it straightforward to see exactly when a crime or an incident took place. This allows a trained digital forensics analyst to string all the pieces together to form a bigger picture of what happened and see whether it matches a witness’ description of the events.

The role of timestamps in CCTV footage

As usual, things are not always as smooth.

• What happens if the recording doesn’t have a timestamp at all?

• What if the timestamp is inaccurate and doesn’t match the actual time of the events?

To answer the first question, in case the CCTV footage lacks the timestamp, unfortunately, this bears a high likelihood of the court deeming it inadmissible. The good news is, most of the modern CCTV units have the timestamp functionality enabled by default.

The answer to the second question can get complicated. Don’t make the mistake of assuming that the mere mismatch constitutes an act of malice. It could be, for instance, that whoever manages the CCTV unit simply didn’t bother to set the correct time and date upon setting it up for the first time. It happens. Or, it could be due to connecting to the incorrect NTP server.

If the video footage doesn’t have a timestamp, the court could render it inadmissible as evidence.

The power of electrical network frequency analysis

If the video footage does not have a timestamp, not all is lost. Thanks to the electrical network frequency analysis, a modern audio forensics technique, it’s possible to analyze the background mains hum in the footage and compare it with mains frequency database logs to see if it matches a pattern that is indicative of a certain time period.

Think of it like an audio watermark of sorts. This can help audio and video forensics experts pinpoint when the recording was created even if it lacks a timestamp or the timestamp is wrong.

The video file may contain valuable metadata that shows the whereabouts of the crime

Let’s imagine a scenario where we’re dealing with a smartphone recording rather the one recorded by a CCTV unit. In this case, a trained forensic video analyst can access a treasure trove of data that’s being stored in the video file’s metadata.

This includes:

• GPS location
• Creator’s ID
• Camera ID
• Date of upload

Of course, the above data is only stored in case the appropriate smartphone setting is enabled. Otherwise, it could only contain other pieces of information such as the lens type, focal length, aperture, shutter speed, and others, none of which are likely to get you any closer to solving the case.

A smartphone video recording can contain vital information such as what type of device it was recorded with, the exact GPS coordinates, and more.

SalvationDATA's products are revolutionizing the video forensics industry

o provide law enforcement personnel an edge against crime, SalvationDATA has developed 2 forensic analysis tools that are revolutionizing the audio and video forensics industry.

Presenting:

Video Investigation Portable 2.0

Thanks to VIP 2.0, it’s incredibly easy to find exactly what you’re looking for. This forensic video analysis software will help you save tons of time by automatically identifying the timestamps of interest based on your custom search criteria.

For example, let’s suppose that you’re looking for a red vehicle that ventured toward North, but you have a whole day’s worth of video footage to go through. Simply input these parameters, and VIP 2.0 will tell you the exact time this happened and show you the corresponding video footage with its Intelligent Video Retrieval feature. Then, you only need to zoom in on the license plate numbers, and you’ve successfully identified your suspect!

Plus, VIP 2.0 preserves the metadata associated with the video file and thus makes it admissible in court. Have you tried the free trial yet?

SVR for HikVision

SVR for HikVison is the world-leading video recovery tool for HikVision, one of the most popular CCTV brands. With its help, you’ll be able to successfully extract the video footage you’re looking for, even if the CCTV system is protected by a password. By using this digital forensics video extraction tool, there’s a good chance you’ll be able to access the files, even if they have been damaged, formatted, corrupted, or overwritten.

Its built-in video preview player allows you to take a look at the interesting bits straight from the software itself without requiring any third-party video and playback software solutions. It’s incredibly time-efficient since it allows you to scan the exact sector you believe the files are located on. In case the video’s timestamp is incorrect, it will automatically correct it for you, so you’ll be able to see the correct time of when the incident was taking place.

Since there’s a no-strings-attached free trial, there’s no reason not to give it a try.

Conclusion

The field of audio video forensics is full of pitfalls, challenges, and curveballs. However, with the right knowledge and tools, digital forensic investigators and law enforcement personnel can efficiently recover and analyze the footage, pinpoint the whereabouts of the crime, and bring those responsible to justice.