I stand corrected. First, I did find a reference to Pixel Aspect Ratio (PAR) and down sampling uncompressed NTSC video in the joint Forensic Imaging and Multi-media Glossary (PDF) published by the IAI and LEVA, the final version of which was released in July, 2006. Second, in an effort to simplify this discussion, I’ve over simplified the Interpolation Methodology I described in Part 2. I will be expanding on that in this post, in far more detail than I had originally intended.

I was hoping I’d be able to wrap this series up with this post, but it’s clear to me now that I won’t be able to. There’s simply too much to cover and I’m certain that at least a few are still scratching your heads (like I was), wondering why we shouldn’t just rely on the pixel matrices to calculate Pixel Aspect Ratio (PAR) from analog sources. It is critically important to understand that I am approaching this topic from a forensic perspective, with the goal of standardizing the methodology used for forensic processing, interpretation, and presentation.

Dept: 2233F

Position:Advanced Specialist 1 – Forensics (FOR) (TS6NP)

Title: Audio-Video Examiner

Specific Responsibilities:

Candidate will work within a fast-paced dynamic audio-video exploitation laboratory environment serving customers in the military, law enforcement, and intelligence community.

The position will be responsible for the forensic examination of audio and video, including the exploitation and enhancement of audio, video, and still images. The position will be responsible for providing results in finished products or detailed analytical reports. The position will require attendance at meetings and collaboration with internal and external resources to remain knowledgeable on rapidly evolving digital media technology.  The position will collaborate with software engineers to research, evaluate, test, and validate new audio and video forensic products.

Turns out I may just know a thing or two about Mass Video Evidence Collection & Processing.  Who knew?

I have worked several cases that were comprised of thousands of hours of video evidence collected from dozens of sources, including the Vancouver Stanley Cup riots.

Forensic Video Analysts from around the world were brought to Indianapolis to work together, and although I wasn't there, I was responsible for supporting the infrastructure and solving the DME workflow issues that couldn't be resolved efficiently on-site.

It’s sometimes difficult for traditional Computer Forensic (CF) examiners to understand why they should treat video and multimedia any differently than other types of digital evidence. After all, a bit is a bit, and a byte is a byte. Right? CF examiners are typically highly trained and highly technical people. If anyone is going to understand how to recover and interpret multimedia data, one would think that a traditional CF examiner would be at or near the top of your go-to list. The problem with this assumption is that multimedia data is fundamentally different than most other types of data, and in more than one way.

Understanding video standards is fundamental to aspect ratio correction. Back in the predominantly analog days we had three main standards referenced or used for most video recordings; NTSC, PAL, and SECAM. Then in the early ‘90’s came the first digital multimedia frameworks to reach the average consumer; QuickTime and, shortly thereafter, Video for Windows (VfW).

Today we have dozens of multimedia frameworks, digital video and digital display standards, all of which lead to a great deal of confusion regarding the plethora of acronyms and what they truly mean. AVC or H.264? HEVC or H.265? CIF or SIF? Don’t even get me started on the profiles and parameters available for each standard, as the combinations are truly mindboggling. When it comes to proper Display Aspect Ratio (DAR) though, it really boils down to “Are the originally recorded pixels square or non-square?”

* Updated with Corrected Images & Explanations. 

After the break you'll find several images of a bogus Person of Interest (PoI) that were recorded by a DCCTV system. Two different analog CCTV cameras with built-in IR illuminators were connected to the black-box, h.264 DVR. These JPG images were exported from the DVR’s proprietary player. All of these images exported at 704 pixels by 480 pixels. When the recorded video is played back via the proprietary player it is displayed at 630 x 455; however, analysis of the proprietary file and exported AVI files reveals both of those contain a 704 x 480 video stream.

Your task, should you choose to accept it, is to:

• Describe the PoI’s clothing items from these images as you would for producing a BOLO. Note any issues that may affect your description.
• Identify the single most important correction that should be made to these images prior to printing. (BONUS - Why does this correction need to be made, and what tipped you off to it?)

If you’ve taken one of my recovery classes or attended one of my presentations on the topic at a LEVA conference or other event, you may have seen these examples.

I probably should’ve just dropped the mic after the last post, but we’re going to continue on. I’m not one for dropping names, and in this case I don’t have to either. Everyone has gotten this wrong at some point, and I mean everyone. The people working on related standards; the people making the world’s leading non-linear professional editing systems; the people who make a living professionally processing and transcoding video; the people making multimedia playback software; the people making DCCTV systems; the people making operating systems; and yes, even forensic video and digital evidence technicians and analysts. We’re all human, my friends. It is a long, convoluted, complex process with its very foundation based on sampling an analog signal.

Let’s talk a little more about aspect ratio. Always a lively topic everywhere I go, and regularly misunderstood by industry leading CCTV equipment manufacturers, engineers, and other video professionals. Should we correct, when do we correct, how do we correct, and of course the why. I’ve done a few short posts on the topic in the past (here's one), but this will be in a little more detail. Still writing on the fly, just going to break it down into a few posts over time.

Several other things I should be doing on a Saturday morning, but I find myself anxious to continue this discussion. Maybe it’s because although multiple industry Best Practice documents talk about correcting Aspect Ratio, none of them discuss the proper way to do it. It could also be my new coffee maker, which I'm hypothesizing has increased my caffeine intake substantially, although I have not increased my coffee intake. Who knows. Anyway, let’s start by recapping Part 1.

Evidence Technology Magazine has published their May-June, 2010 issue featuring a story on Forensic Video. The story was written by LEVA's Principal Forensic Video Instructor and features several LEVA members. The question you need to answer: Can video evidence be trusted?

Full Story

The Hamilton Police Service (HPS) is currently looking to fill the position of Forensic Identification Video Technician, which will be located in downtown Hamilton at their Central Police Station.

Click here for details (PDF)

LEVA will be providing their Forensic Imaging Techniques course May 27th - 29th, 2009 at the LEVA DME Lab, which is located at the University of Indianapolis. Visit the LEVA training schedule for the latest on all of the LEVA's course offerings.

January 26-29, 2010 the Corona Police Department will host the Ocean Systems training course "Forensic Video Analysis - FVA 101, Introduction to Forensic Video Analysis".

The learning environment consists of lectures and hands-on exercises designed to allow the analyst to become familiar with the dTective system while working on real cases. Class is limited to 10 students so click here to find out more and get registered today!

LEVA is conducting a one week hands-on forensic video analysis program in Cheshire, England, June 15 – 19, 2009. The event is hosted by Key Forensic Services, a leading provider of forensic solutions in the United Kingdom.

Digital Video Evidence: The Quest for Accuracy and Reliability is developed for the beginner to advanced level analyst. This unique program is designed to share scientific techniques and methodologies employed to ensure the accuracy and effectiveness of video evidence and to maintain its credibility in the courtroom.  For complete details click here.

The Ministry of Community Safety and Correctional Services, Ontario Provincial Police, is seeking a qualified individual to examine and analyze audio/video recordings for the purpose of developing, enhancing and clarifying evidence, and presenting, defending and supporting associated findings in courts of law as required; undertake research and maintain ongoing research and forensic studies related to the sciences of digital audio processing, digital image processing and video recording technologies, both analog and digital. To attend crime scenes and recover evidence using sophisticated audio/video equipment for examination as required and to provide training and guidance to colleagues/front line officers and assist Manager in equipment maintenance and policy as they relate to these sciences.

Complete Details

A brief video discussing the basics of multimedia metadata analysis & some of the Open Source and/or Freeware solutions that can help. Solutions discussed include:

• Exiftools, by Phil Harvey - https://exiftool.org/
• MediaInfo & MediaInfoOnline - https://mediaarea.net/en/MediaInfo​
• FFprobe & FFmpeg - https://www.ffmpeg.org

Medical experts, accident reconstruction experts, and other types of experts are frequently asked to interpret data from images that were obtained from video evidence. When these experts have no training or background in processing multimedia evidence, and/or make no effort to consult someone who does, bad things generally happen. Really bad things, like having all of their evidence thrown out of court, for one.

Posted by Larry C. on behalf of James M. Kennedy.

The New York State Police Forensic Video/Multimedia Services Unit has approval to fill newly created positions in the Forensic DME Section and the Video Production Section of the Unit. Information on the first phase of hiring can be seen at the link below. Feel free to forward the link to anyone who you feel may have interest in the positions. Any questions and/or interest can be directed to myself using the contact information in the below email signature.

The Minneapolis Police Department Crime Lab is seeking to hire a Forensic Video Analyst. Applications will be accepted from Monday, October 22, 2012 through Friday, November 9, 2012. Complete details can be found online at www.minneapolismn.gov. A direct link to the city's job listings is provided below for your convenience.

Minneapolis Career Opportunities

LEVA will be providing the Advanced Forensic Video Analysis & the Law course September 14th - 18th, 2009 at the LEVA DME Lab. Only graduates of LEVA's Basic and Intermediate “Forensic Video Analysis and the Law” courses may apply, and seating is limited.

Visit the LEVA training schedule for the latest on all of LEVA's course offerings or click here for the complete advanced course details (PDF).

LEVA has announced that they will be providing their Photographic/Video Comparison Course May 18-22, 2009 in the LEVA DME Lab at the University of Indianapolis. The Photographic/Video Comparison focuses on the science of comparing known objects, vehicles, clothing and humans with CCTV images of questioned objects, vehicles, clothing and humans.

For LEVA's complete training schedule - click here.

LEVA has announced a special reduced pricing package to help government agencies meet their training requirements in these challenging economic times.

As of January 1, 2009, LEVA will bundle its prestigious 40-hour core training courses and others, providing significant cost reductions. All courses are conducted at LEVA’s Digital Multimedia Evidence Processing Lab at the University of Indianapolis, Indiana. Visit the LEVA Website for complete details.

The Law Enforcement and Emergency Services Video Association is providing a free course — Video Essentials for First Responders — for attendees of its 2013 LEVA Digital Multimedia Evidence Training Symposium, which runs Sept. 9-13 in Asheville, N.C

Full story

Hard to believe that next week's 2011 LEVA Training Conference is already upon us. I'll be out in Coeur d'Alene all next week, and I'll be giving a presentation on the AVI file format and VirtualDub at the conference late Thursday afternoon. There are tons of great training sessions going all week long. Hope to see you there!

LEVA has announced the next Level 1 training course, which will be held at the LEVA DME Lab September 28th - October 2nd.

The Law Enforcement & Emergency Services Video Association has announced the introduction of a new certification. LEVA will now confer Certified Forensic Video Technician (CFVT) status on students who have performed video evidence processing for at least one year and successfully complete its three core courses within a five-year period:

• Basic Forensic Video Analysis & the Law,
• Intermediate Forensic Video Analysis & the Law and
• Advanced Forensic Video Analysis & the Law.

The courses, totaling 120 hours of lecture and hands-on instruction in LEVA’s Digital Multimedia Evidence Processing Lab at the University of Indianapolis, are designed to lead students to an advanced level of competency, knowledge and skills as Technicians in the science of forensic video analysis.

More Info...

http://media-geek.com/images/myblog/frontpage/ft-worth.jpg LEVA's 20th Anniversary Training Conference will be held in Ft. Worth, Texas November 18th- 20th.  As usual, LEVA is organizing some great pre-conference training as well as a vendor exhibit hall.  For more information or their official registration form click here.

Magnet Forensics launched the evolution of DVR Examiner today, Magnet WITNESS.  WITNESS includes all of the capabilities of DVR Examiner plus many new features, essentially creating a single solution to acquire, review, analyze and report on all of the video evidence from your case, regardless of source.  Proprietary DCCTV systems and files, cloud CCTV sources such as Ring & Arlo, MP4 & AVI exports from other sources such as in-car and body worn systems.

Unlike DVR Examiner, WITNESS includes the ability to create sub-clips, create synchronized previews, convert proprietary DCCTV files and more.  Learn more at https://www.magnetforensics.com/products/magnet-witness/

by Thomas C. Christenberry, "Digital Multimedia Evidence Processing Laboratory - Training," The Police Chief 77 (March 2010): 62–63, http://policechiefmagazine.org/magazine/index.cfm?fuseaction=display&article_id=2041&issue_id=32010

"For many television viewers and forensic science enthusiasts, shows like CSI and the spin-off television shows CSI: Miami and CSI: New York are fun to watch and, with their various characters and story lines, continue to fascinate viewers of all demographics. Viewers anxiously marvel at the forensic technology, the latest scientific methodology, and the amazing deductive skills of the forensic specialist. Best of all, the whole case is completed in just one hour."

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