Dear friends, welcome! The time has come to say farewell to this blog post series! This last post will look back at what we have learned in previous weeks and provide links to all of the 17 posts. We hope that you can use this as a basic knowledge base for future reference and perhaps even share it with your colleagues!Continue reading
Category Archives: Video Evidence Pitfalls
Metadata: So Useful But Not So Reliable
Dear friends, welcome to this week’s video evidence pitfall post! We often hear about the importance of metadata as a way to reveal more than pixels alone would. While it’s certainly true that metadata can give us lots of useful info, they must be looked at carefully and prudently, as they hide several pitfalls – keep reading to discover some!Continue reading
Multiplexing: The Cause of Many Seemingly Corrupted Videos
Dear friends, welcome back! Let me just say it was so nice to meet many of you at the Amped User Days last week, even though virtually. Ok, back to us: welcome to a new chapter of the Video Evidence Pitfalls series! Today we’re dealing with multiplexed videos: we’ll briefly look at different kinds of multiplexing, how to recognize them, and how to bring your video exhibit back to a “normal” form. So keep reading!Continue reading
Cognitive Bias: Steering Conclusions Irrationally
“Thou shall peer-review your analysis” is one of the well-known (and often ignored) rules of forensic reporting. Sometimes, this important principle gets poorly translated into: “let’s have a colleague peek into my results”. And so, it may happen that an investigator or examiner will ask a colleague for their opinion before submitting the results.
Issue: Being Objective Isn’t That Easy
Let’s imagine John calling Lucy to his desk and asking her: “Can you help me with this license plate? I can read BC 537 but I can’t seem to get the last two characters, perhaps they are “TT”, and I’m also quite uncertain about the first one.”
What should Lucy tell John?
- Sure thing! Let me help you with my independent review.
- Er… you’ve just burnt me as a potential reviewer of your work.
Compression Artifacts: Hiding or Adding Details to the Scene
Dear friends, welcome to a new video pitfall post! This time we’re dealing with a very sneaky part of video analysis: can we trust what we see? Sometimes, distinguishing the real detail of an object from that of an artifact is not easy. Today’s post will review some of the most common video artifacts and their possible effect on your work.Continue reading
Timestamps: Not Always Showing the Right Time
Dear friends, welcome to this week’s video evidence pitfall! In this post, we’re focusing on a crucial element of forensic video analysis: timestamps. Timestamps allow us to locate in time what’s shown in a recording, or reference an event to a specific moment in time. Although virtually all surveillance systems do record timestamps, you should be aware of several pitfalls in accessing and interpreting them, so keep reading!Continue reading
Receiving Video Evidence: Usually It’s Not the Original
Dear friends, welcome to another video pitfalls pill! Today’s post concludes our mini-series about using the “best possible evidence.” In the previous weeks, we always assumed you had control from the beginning. Today, we focus on a different yet widespread scenario: you receive the “evidence” from someone else and are asked to work on that. Want to know the undercover pitfalls in this situation? Just keep reading!Continue reading
Screen Capture: It’s Not the Evidence, It’s a Video of the Evidence
Dear friends, welcome! Here we are with one more post for the “best possible evidence” mini-series. In the past two weeks, we’ve seen that you should not film the display and that proprietary players often alter the original pixels. Today, we’ll close this mini-series talking about screen capture. We’ll see that, while being much better than filming, this approach still has its issues and should be used only as a last resort. Keep reading!Continue reading
Proprietary CCTV/DVR Players: Often Not Showing the Original Pixels
Dear friends, welcome! This week’s post continues the “best possible evidence” mini-series. Last week, we showed why filming the display is not good. This week, we address a related topic: can we trust proprietary players? You’ll be surprised by the number of pitfalls hidden in the bare playback of a surveillance video, so keep reading!Continue reading
Cell Phone Snaps: Bad Quality and Reliability
Dear friends, welcome to your weekly dose of fear! Starting from today, we’ll be addressing a fundamental issue, perhaps the most important in your video forensic workflow: using the best possible evidence. We’ll dedicate some posts to this important topic, covering the various pitfalls you may encounter. Today, we’ll see why using a mobile phone (or even a professional camera on a tripod) to capture footage is, well, not recommended. Keep reading!
Issue: Filming the Display Creates Awful Footage
Let’s start with a quote from one of our esteemed users:
The jobs I manage never get that far as we work with appalling quality footage in the vague hope of securing a conviction.
Well, it’s certainly true that, sometimes, there’s not much we can do. But in many cases, the “appalling quality” is due to how the evidence video has been acquired, or how the working copy has been produced. Let’s go practical with an example. Can you get this license plate?Continue reading