How Can I Correct a Stretched Video That Has Half of the Lines?

Dear Amped fellows, welcome to this week’s post of the “How do I do this?” series! Today we’ll show you how Amped Replay can deal with a not so common yet very annoying artifact: stretched videos due to field-based recording. If the last words mean nothing to you, don’t miss this opportunity to learn something new!

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See You at the IAI Annual Educational Conference in Nashville

Join us at the IAI Annual Educational Conference from 1- 7 August at the Gaylord Opryland Resort & Convention Center in Nashville (US).
You can find us in booth 525!

Don’t forget to follow all of these very exciting and interesting Amped Software sessions:

Basic principles of Image and Video Authentication
Presenter: Blake Sawyer
August 3, 08:00 – 08:45 CDT

In a world where a picture or video can have a crucial impact on nearly every investigation, making sure that media is what it purports and hasn’t been tampered with is paramount. This course will talk through differences in the authenticity of an image and the integrity of an image. We will then describe methods means to identify both file integrity and image authenticity.

Video Evidence Pitfalls
Presenter: Blake Sawyer
August 3, 08:50 – 09:30 CDT

While video is more readily available to aid in investigations today (e.g. CCTV, Body-worn, social media, and cellphones), there are several questions that may be asked of a video and that may not be able to be answered just by hitting the “Play” button. Understanding how video from sources can affect what we see when evaluating video is crucial to any evidence, and the eye is prone to see things differently than it is recorded. Learn why it is crucial to understand how the video is played and make sure the answers we get from the images are accurate.

Video File Analysis: Understanding the Data Behind the Images
Presenter: Blake Sawyer
August 4, 13:00 – 17:00 CDT

In this workshop, examiners will get an understanding of how a video is made at a frame level, how to examine and interpret metadata available to a video container, stream, and frame; and different methods to validate that data. Attendees should contact the instructor beforehand if they wish to use any of their own files in this workshop.

About the conference

The IAI Annual Educational Conference provides a full week of high-quality, cutting-edge education and hands-on training in forensic physical evidence examination and crime scene processing. You will be able to join lectures on the latest technology, techniques, and research, sign up for workshops to practice basic to advanced skills, and attend meetings and panels that provide an opportunity to discuss the latest professional topics and developments.

Find out more about the conference and register today!

See you there!

An Interview with Andrew McDonnell from the HM Revenue & Customs of the UK Government

Andy is one of the most respected forensic video analysts in the UK. In this interview, he shares his point of view on forensic video analysis and the industry at large. I want to highlight his very insightful observation about the situation we have been fighting since our beginning: “A widespread fundamental misunderstanding about the complexity of audio-visual forensics work.”
Enjoy the read!

Martino Jerian, Amped Software CEO and Founder

Andrew, tell us a bit about yourself. What is your background and your current role at HM Revenue & Customs?

I’ve been around a long time. My career started in 1983 with military communications engineering in the Royal Air Force where I did seven years, four of which were spent in Germany which I loved.

I then moved into broadcast television where I spent twelve years managing technical teams such as TV camera crews, sound and vision engineers, directors, production assistants, technicians and video editors for a number of companies including ITV, Sky TV and a number of outside broadcast companies. I used to design and build TV studios, galleries, transmission facilities and OB trucks.

Following redundancy from one job I saw a role advertised in the police, managing teams of audio-visual forensic specialists, so that opened up my current career where I’ve spent 16 years in West Yorkshire Police – and I’ve been working with HM Revenue & Customs for two years now.

What made you decide to enter the field of multimedia forensics?

In all honesty, it never occurred to me that such a career existed. Having spent time in the TV world I had no idea that the police used video (and audio, photography and CCTV) in a forensic way.

It was only when I switched career that I realized there was a whole new world of opportunities beyond TV, and I have genuinely never looked back. The big difference is the feeling that you’re doing something worthwhile, using technical skills in a way that makes a difference in society. That sense of civic duty is something I share with many colleagues, and this is why we love what we do.

What would you say are the biggest challenges with video evidence during investigations and when presenting it in court?

In the UK policing world, there are two major challenges. The first, sadly, is financial. Not having budgets to properly train and develop staff, invest in the latest technology, or provide sufficient resources to meet the demands are all very real and difficult problems for police managers.

The second is volumes of data. Video evidence is everywhere these days. From CCTV in public and private spaces, to doorbell cameras, dash-cams and helmet cameras on cyclists, to body-worn video on police and other officials, mobile phone videos from members of the public and social media content. And with image quality continuing to improve, HD and UHD video is resulting in huge demands on data storage and processing.

Since changing jobs, I have found that within HMRC, unlike many in the wider law-enforcement community, there is a genuine desire to invest in staff, provide training and development and provide the tools we need to do our job to a world-class standard.

What would you say are the main forensic challenges surrounding image validation? How can they be addressed?

Keeping up with technology is always a challenge. It always amazes me how every new technology can be very quickly picked up and utilized in criminal ways, often before it becomes mainstream technology. 

In the current climate, social media imagery, for example, is so difficult to validate. With the growth in augmented reality and AI/machine learning capability this is becoming an ever more difficult challenge.

I think the real problems for law enforcement are yet to come and will only be addressed when new tools are developed, which leverage emerging technologies in a different and innovative way.

To achieve this, two things are required:  real and significant investment in audio-visual forensics, and genuine recognition of the problems with a desire to solve them.

In your opinion, how important is it that digital forensic techniques and tools are based on the scientific method?

I think it’s essential. The scientific method not only provides rigor and quality assurance, but it also provides gravitas.

Future investment in crime fighting will come from the need to tackle digital crime: cyber, cyber-enabled, digital forensics, audio-visual forensics, mobile phone work, etc. It’s a growth area. This investment will only happen if the forensic community is seen to be operating in a professional environment and taken seriously.

What are the most important aspects of training and education for forensic image and video analysts?

Any manager of a forensic department must look at what the job involves. What are the tasks that need to be performed, and to what standard? This is the starting point. It enables managers to identify what skills their staff need and to recognize where the training should be delivered to fill any skill gaps.

Training should be based on business needs and on competency requirements. It is critical that the outcome of training is that staff become competent at what they do and this needs to be demonstrated by having training that is independently accredited.

We cannot produce a set of validation tests and documents that cover every single possible scenario of how a piece of media might be handled in a forensic workflow.

But we can give the practitioners the tools and knowledge they need to make informed and professional decisions. That way we can trust they will make good judgment decisions based on sound rationale and be confident they have approached each task correctly.

How do you think the world of image and video forensics will change over the next few years?

There will be more video of higher quality which will need to be managed, stored, processed, and presented without adding delays to the workflows. Processing and analyzing big data will continue to be a growing challenge. CCTV image quality will improve bringing great opportunities to make the best use of forensic tools.

I can see facial recognition being a big new area for us. I am optimistic that audio-visual forensics will be taken more seriously as forensic science and will become mainstream.

Recently there have been a few changes in the UK landscape. Digital Evidence Management Systems (DEMS) are being implemented in several forces and the new version of Digital Imaging and Multimedia Procedure (v.3.0) has been published. What challenges does this pose to the use of video evidence, especially in relation to CCTV? How does this affect our daily work with video evidence?

It has always been the case that video/CCTV evidence arrives in many formats. Once under the control of law enforcement, the chain of evidence must begin, and the integrity of the evidence must be maintained. This is true for all evidence, be that a knife, fingerprint lift, or CCTV file.

National guidance for video evidence states an evidential Master must be created using W.O.R.M. (Write Once, Read Many) media such as CD/DVD data disk or a secure server. If another copy of that video is required, a Working Copy can be produced. It is important that the Working Copy remains forensically the same as the Master, bit for bit.

If I alter the nature or content of that file (such as creating a shortened clip of the video, creating a still image from one of the video frames, enhancing the video, or converting it to a different file format) I now have a product which is different. This is not a Working Copy, it is a new derivative, which must be defined as a new Master. That’s the fundamental basic rule.

Now, with that in mind, let’s look at – a scenario. If I take a proprietary CCTV file (.dat as an example) and upload that to a police Digital Evidence Management System (DEMS), I would expect the DEMS to hold a Master copy of the .dat file (and perhaps a Working Copy of it).

A smart DEMS would also recognise the .dat format and transcode it to a playable .mp4 file which can then be viewed in a common video playback app such as Windows Media Player. In doing so it would have created a new Master (the MP4 file is significantly different from the .dat file, so is a new Master). This is also true of practitioners who transcode the video – they should understand that they have changed the content of the file and have now created a new Master.

The problem is that many DEMS systems and many practitioners will transcode the file to create a playable format but store it as a Working Copy of the original, rather than a new Master.

This happens because there is a widespread fundamental misunderstanding about the complexity of audio-visual forensics work. If we are to avoid legal challenges in court the integrity and authenticity of our evidence must be secure. System manufacturers and senior decision makers in this field need to understand the technical challenges, or at least take advice from the technical experts.

How did you learn about Amped Software?

While contributing to a UK national CCTV steering group we recognized that there was no “standard” for AV training.

With the emergence of ISO 17025, we recognized that we needed to set the framework for training and competency. This led me and others to develop the national CCTV competency framework and, as a result, identifying training providers who could deliver high quality training to UK practitioners.

This in turn led me to Amped FIVE as a tool that could provide what we needed in terms of forensic processing and analysis of video files.

Why did you choose Amped Software products?

We use a wide range of tools, depending on the nature of the task at hand.  What we do like about Amped FIVE and Amped DVRConv is the close-knit community that exists around them.  

There is a strong professional community that shares ideas, suggestions, methods and generally helps each other out. The company is also keen to evolve and develop and in doing so really does listen to its users and takes on board their requirements and ideas for development.

Do you have any interesting stories or success cases related to Amped Software products?

We often find that we can pose a question about a particular CCTV file format (as we know there are over 3,500 CCTV systems in the UK marketplace and that number increases weekly).

Usually, in a very short timeframe, we receive a response back which is either “we’ve had that before, try this solution…” or “send us some details and a sanitized image and we’ll reverse-engineer”.

When you are not busy looking at digital evidence, what do you like doing in your spare time? 

I love walking in the hills around Yorkshire (we have five national parks close by) with friends. I also enjoy taking my wife and children on cycling trips. Other than that, depending on the amount of time available I enjoy reading biographies, cinema, restaurants, international travel, photography, and single malt whisky.

 

Amped Replay Update 21282: Smart Processing, Detailed Reporting and Improved Format Support

Here we are again for another blog post update, this time for Amped Replay – the enhanced video player for frontline officers and investigators.

Before we get into what’s new, let us just look back for a moment. In the two years since Replay launched it has quickly become the go-to application for those early moments in a video investigation. Converting proprietary CCTV formats, finding an offender or incident, performing simple enhancements using science-based image processing filters, and then we have the easy annotation and tracking and magnifying. And we cannot forget the automated reporting.
Officers now have a powerful but easy to use tool that enables them to perform general video and image tasks, improve media releases and expedite case files.

If you deal with video in cases, but multimedia is not your sole responsibility then Replay is for you. With these latest updates, we have made it even easier to use!

Let us go through each stage, starting with the Import tab, and see what’s new.

IMPORT

As many of you will know, CCTV and imagery from Video Surveillance Systems are notoriously difficult to manage as every manufacturer can do what they want to their video. We have simplified this challenge by including the powerful Amped Conversion Engine directly into Amped Replay. When you import a proprietary file it is analyzed and made playable behind the scenes. This is a lossless process, conforming to international standards for forensic video processing, and ensures that you are seeing the actual pixels recorded with nothing changed by the conversion process or the player’s presentation.

In this update, we have added 6 new extensions including the .G64A and .EZVP formats. More format variants have also been added including one for the popular .H264 format.
A format variant is a change in structure to a format that we have supported in the past.

We have been working really hard on timestamps over the past few months and in this update, we have 7 new time formats.

If you want to learn more about the Amped Conversion Engine, why not take a look at this recent article on Forensic Focus.

PLAY

The first thing you will notice with the playback stage is some new information at the bottom.

We have added the pixel dimensions here, and this information will change if you alter the size of your video or image. So, if you start with a video of 944 x 1080, but you adjust the aspect ratio to 16:9, you will see the pixel dimensions change to 1920 x 1080. It will always display the size that you will export at, and this information will always be visible regardless of the stage that you are in. Being aware of the final pixel size of your video is important: for example, if you export a video with a resolution above 1920×1080, expect it to be downscaled when played on most devices to fit the display resolution.

Then we added two buttons next to the speed slider to help you either increase or decrease the Frames Per Second (FPS). You can now either drag the slider, hover over it and use your mouse or click the +/- buttons.

ENHANCE

This is where we have added Smart Processing. What is Smart Processing we hear you ask? Well, Replay will analyze what you are starting with and if that analysis identifies that certain filters should be applied then we automatically apply them for you. Nothing will be done without the user selecting an enhancement process though and you can still override them if required. It’s also worth noting that whatever is selected will be documented fully in the report.

You can see in the image below that we have a strange ‘squished’ video and we have our mouse over the Correct filter group.

As soon as Correct and Auto are selected, the new Smart Processing option will be applied.

Amped Replay has identified that the image must be line doubled to increase the vertical size. You will also notice that the image size at the bottom has also changed to the new size.

In this next example, we have lots of jagged edges in our video.

By selecting Correct, Replay will analyze the video and detect that it requires Deinterlacing.

The Correct filter group deals with analog to digital problems and the new Auto option does a great job in quickly identifying what the problem is and fixing it correctly for you.

We have also added an Auto option to the Aspect Ratio filter group. For this, let us go back to the 944 x 1080 video we looked at earlier.

Rather than squished wide, this is squished thin and it just doesn’t look right. Using the new Smart Processing within Aspect Ratio the image will be adjusted correctly.

You can now see that we have the correct image presentation size.

Video can be captured, encoded, and stored very differently from how it should be presented. Identifying differences in storage and presentation is the key to our new Auto functions. Presenting incorrect footage in the media or in court can cause recognition problems or raise challenging questions. This new functionality has been developed to help those users with limited video knowledge avoid these issues.

For those users that know a little bit about forensic image and video analysis, it is worth pointing out that we do not use the metadata to conduct these changes. Metadata can often be wrong. Analog to digital CCTV recordings are rarely tagged to be displayed at 4:3 aspect ratio. Interlaced video is often stored incorrectly.
The Smart Processing in Amped Replay has been built after analyzing hundreds of cases and is a major step forward in simplifying the decisions that investigators need to make in presenting visual evidence correctly.

ANNOTATE

A few small changes have been made to the Annotate tab after user feedback. We start with the Canvas Extension option.

This is now OFF by default. To better understand how this works, and why the behavior has been changed, look at this frame from a video where I have followed the track to outside of the frame. Tracking is one of the most used features in Amped Replay.

When I export the video or frame, I will not retain the part of the circle in the checkerboarded area. My video size will stay the same and the red circle will move outside of my video. This is what I want to happen.

There are times though that you will want to enable the Canvas Extension. Look at this image and note the size at the bottom.

Now, let us use Magnify:

Even though we have dragged our box out of the image area, the size of our image has not changed. It is still 632 x 940. If we exported this frame or video, half of the magnified area would be cut off. If you see the black and white checkerboard, and you want to keep the annotations, just remember to go to the options and select Extend Canvas. You can then select what color you want it to be.

Next, we have Padding within the Text Tool.

When using the text annotation, you now have the ability to pad the text borders. It is a very simple little change but really smartens up your overlays to ensure that the text is not right on the edge of your graphic.

EXPORT

Within the Export Actions, we have the addition of more options within the report.

You will now find a checkbox to Include Bookmarks in the Report.

Whenever you create a report, either on its own or while exporting processed multimedia, the bookmark thumbnails and any associated description will be included.

You will also notice that all annotations are now included.

The reporting options now make it easy for users to comply with multimedia processing regulations as everything is documented. What you watched, what you did, and what you have exported.

Last, and by no means least, we have the hidden admin file, used when Amped Replay is installed on a police network. This document gives a huge amount of customization power to IT Support Units.

We have now added admin controlled selection of the Hash algorithm used in Replay and documented it in the reports.

You can learn more about the admin-settings.ini file in this Tip Tuesday.

With all the automatic processing, the power of annotation, and now full detailed reporting, Amped Replay really does make it easy for the front line to deal with video and images.

Bug Fixes

  • Fixed a bug that stopped JPEG2000 images from being loaded.
  • Fixed a bug that caused incorrect frame index in interlaced video.
  • Fixed a bug where annotations were set incorrectly in deinterlaced video.
  • Fixed a bug that caused annotations to spin during keyframing.
  • Fixed a bug that presented incorrect frame numbers in the report if Deinterlace was used.

Don’t Delay – Update Today

If you have an active support plan you can update straight away by going into the menu About > Check for Updates within Amped Replay. If you need to renew your SMS plan, please contact us or one of our authorized distributors. And remember that you can always manage your license and requests from the customer support portal.

How Do I Play a Video Frame-by-Frame and Comment Relevant Stills?

Dear friends, welcome to the weekly appointment with the “How do I do this?” series! Browsing a video frame-by-frame is an essential yet invaluable feature for video forensics. And when you spot something interesting, you’ll want to save that position and possibly add a comment. We’ll see how all of this can be done with Amped Replay in a moment. Keep reading!

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How Do I Adjust the Playback Speed of a Video?

Dear friends, welcome to this week’s “How do I do this?” post! Today we’ll show you how to adjust the speed (playback framerate) of your video, and how you can use this feature to export a slowed-down or accelerated version of the video. Keep reading!

Spoiler of the day: within Amped Replay, you can change the playback speed by moving the FPS slider. If you then use Export Processed Video as MP4, it will retain the set speed.

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Come and Meet us at NATIA’s Premiere Event!

We are looking forward to exhibiting at NATIA’s National Training and Technology Exhibition!  The premiere event will take place from July 11-14 at Tampa Convention Center, Florida. 

Come and join us in booth 845 to learn more about Amped Software’s latest technology for your forensic image and video analysis needs! 

About the event: 

Each summer, NATIA hosts its annual National Training and Technology Exhibition. It includes classroom training, hands-on workshops, and a technology exhibition.  In addition, there are many opportunities to network with a wide variety of individuals who are engaged in technical surveillance and specialized support of  law enforcement and intelligence gathering agencies. 

Find out more about the event and how to apply here.

About NATIA

The National Technical Investigator’s Association (NATIA) is a law enforcement training association dedicated to providing top training, technology exhibits, networking, and support to the technical surveillance community. It is comprised of over 3,500 law enforcement, intelligence, and support personnel who provide electronic surveillance, technical operations, and scientific support for hundreds of federal, military, state, and local agencies across the United States and around the world. 

Learn more about NATIA here.

Authenticate Release 21117: Improved Video PRNU, Customizable JPEG Ghosts Plot, Better Batch Processing, and More!

A new release of Amped Authenticate is ready! We have worked hard to improve the performance of several filters and tools, and to make Authenticate more robust to corrupted files. It’s all explained below!

Improved Video PRNU

Video PRNU was part of the latest release, and it gathered lots of attention, as expected. If you’re familiar with PRNU analysis, then you probably know that one important step is extracting the PRNU noise from the reference and evidence frames, so as to be able to compare them. In this release, we’ve improved the noise extraction algorithm, with an impressive impact on performance!

As a benchmark, we’ve used the well-known VISION dataset (freely available here), and run several experiments using the 19 available devices that don’t use digital stabilization, exploring different CRP creation modes and different PRNU Identification configurations. In particular, for creating the CRP, we used three different videos (one flat still video, plus one indoor and one outdoor video, both with moving camera), two different amount of frames (400 and 900), and two possible frame selection modes (All and Group with a size of 25). So we had a total of 19 x 3 x 2 x 2 = 228 CRPs.

We then tested each CRP against 4 videos of the same device (to keep it realistic, we only tested against non-flat and non-still videos) and 4 videos from other devices picked at random. For each test, we used two possible amounts of frames (400 and 900) and two possible frame selection modes (All and Group with a size of 25). That gave us a grand total of ~7200 identification tests.

We repeated the same tests using the previous denoising algorithm and the new one, and then we compared the performance in terms of the discrimination power of the obtained PCE scores, which was measured using the Area Under the Curve (AUC). Basically an AUC value of 0.5 means “random guessing” and an AUC value of 1.0 means “perfect accuracy” (under the considered test settings, of course!). Here’s some performance comparison, separated based on different CRP and evidence creation modes.

Despite the previous algorithm already achieved good performance (AUC was above 0.9 for most devices), we can definitely say that the new denoising algorithm performs even better! We also checked if we needed to change the default PCE threshold proposed by the software, currently set at 60. In the plot below, you can see the distributions across the 19 devices of the true positive rate (green boxes) and false positive rate (red boxes) obtained for increasing threshold values. For each box, the black horizontal segment shows the median value, the solid-filled part covers the 25th to 75th percentiles, the thin line covers all samples that are not considered statistical outliers, and isolated circles mark every single outlier.

You can see that a threshold of 60 seems a safe choice for the considered tests, with most devices showing no false positive under any settings. If we set the threshold to 60, we can then summarize and compare the overall performance, as in the tables below.

Evidence Mode: AllEvidence Mode: Group (25)
CRP Mode: AllTP: 98.97% | FP: 0.0%TP: 94.28% | FP: 0.11%
CRP Mode: Group (25)TP: 92.30% | FP: 0.11%TP= 79.78% | FP: 0.44%
True positive (TP) and False Positive (FP) rates obtained using the NEW denoising algorithm on the considered dataset, using a PCE threshold of 60. Performance is separated for different CRP and evidence frame processing modes.

Evidence Mode: AllEvidence Mode: Group (25)
CRP Mode: AllTP: 73.03% | FP: 0.0%TP: 80.66% | FP: 0.15%
CRP Mode: Group (25)TP: 78.71% | FP: 0.97%TP= 66.53% | FP: 1.42%
True positive (TP) and False Positive (FP) rates obtained using the PREVIOUS denoising algorithm on the considered dataset, using a PCE threshold of 60. Performance is separated for different CRP and evidence frame processing modes.

However, when working on a case, we always recommend validating the threshold in your specific settings (e.g., gathering images from other devices of the same model and running some experiments).

Customizable JPEG Ghosts Plot

The JPEG Ghosts Plot is much appreciated because of its versatility (it can be used on images of any format) and because it can effectively reveal possible previous JPEG compressions in an intuitive way. If you’re not familiar with this filter, take a look at this dedicated blog post: you’ll love it! However, in a nutshell, the filter works by iteratively recompressing the image to JPEG at increasing qualities, computing the total difference between the evidence image and the recompressed version, and eventually plotting the total difference obtained through all iterations (that is, for each recompression quality).

Now, if you have a 40 megapixels image, recompressing it 100 times, like the JPEG Ghosts Plot has been doing until now, can take some time. Moreover, nowadays it’s hard to find a device or software that will compress an image to a quality factor less than 50. We thus decided to let you decide! You can now set the minimum of the quality range to be explored by the filter. The default value is 50, but of course, you’re free to customize the filter’s configuration and turn the value back to 1, which would give you exactly the same plot you were used to.

Of course, this modification is backward-compatible: if you load a project created with an older version of Authenticate, you’ll be warned that the JPEG Ghosts Plot filter is missing the new parameter, and it will be automatically added. To preserve identical results, when loading an older project the default value of the filter will be 1 and not 50. Similarly, if you’re updating Authenticate and you are using some customized startup settings, we won’t overwrite anything. You’ll just see that, in your customized filter list, the JPEG Ghosts Plot has now the additional parameter, set to 1 to preserve backward fidelity.

At any time, however, you can use one of the “Reset default” buttons to restore the factory settings, where the JPEG Ghosts Plot has a default value of 50 for the minimum quality, as shown below.

Better Batch Processing

This one comes from our loyal users! We’ve been notified that, when running a Batch File Format Analysis or Batch File Format Comparison, Authenticate could hang if a corrupted image file was encountered. We understand it would be very annoying, especially if you had left the software running at night time to process 10.000 images, and it stopped at image number 4.

We’ve thus improved the robustness to corrupted files: when a problematic file is found, the processing will continue, and the issue will be reported in the results table.

Showing the Hash of Decoded Pixels

For a long time, Amped Authenticate has been showing the image file’s MD5 and various SHA hash values in the File Format filter. However, with this update, we have a new entry:

The Decoded Pixels MD5 provides the MD5 hash computed on decoded pixels. What’s the difference compared to the “classical” MD5 of the file? Imagine someone has a picture in their computer and creates a modified version of it where only metadata is changed. For example, they may use Exiftool or Windows Explorer to change the Exif make and model, or the acquisition date. Let’s imagine also that they forget to erase the original file. While altering metadata would change the hash of the file, it would not change the hash of pixels.

So if you’re using Batch File Format Analysis on a folder, you may sort by the Decoded Pixels MD5 folder to reveal if there are images with exactly the same pixels and focus the attention.

Search Images From Same Camera Model (CameraForensics): More Info Available

It’s no secret that reference images are a great asset for image authentication. If you’re investigating the integrity of an image, indeed, nothing is more valuable than having other pictures captured by the same camera model and, possibly, running the same firmware, as discussed in this blog post. When there is no time (or budget) to buy the same device and capture pictures, you can still use Amped Authenticate tools for searching reference images on the web. And if you have a subscription to CameraForensics, the search is much faster and cleaner thanks to our integration!

In this update, we’ve added more information to the output table produced by this tool: you’ll be able to see the webpage where the image is posted (which is often different than the image’s URL, that is, where the image file is stored). Moreover, if the image is hosted on Flickr, you’ll be now able to see the Flickr User ID. This can turn very useful if you’re downloading images for PRNU validation. Indeed, it seems reasonable to assume that a Flickr user owns only one exemplar of a specific smartphone/camera model.

Updated JPEG Quantization Table Database

We’ve added to Amped Authenticate’s JPEG Quantization Tables database the QTs used by several recently released smartphones, such as Apple iPhone 12 and Samsung Galaxy S20 (plus their variants), and several Huawei models.

Fixed bugs

We’ve fixed some bugs. If you spot any issue when using Authenticate, please let us know via our support portal, so we can fix it!

  • Fixed a bug that caused the Histogram Equalization filter not to be applied as soon as the filter was selected;
  • Fixed a bug that caused, under some circumstances, some extra text characters to appear below pictures in the Report;
  • Fixed a bug that caused wrong nesting in the Report’s Table of Contents (did not affect the actual report content).

Don’t Delay – Update Today

If you have an active support plan you can update straight away by going into the menu Help>Check for Updates Online within Amped Authenticate. If you need to renew your SMS plan, please contact us or one of our authorized distributors. And remember that you can always manage your license and requests from the customer support portal.

How Can I Trim a Small Part of a Large Video Without Losing Quality?

Dear friends, here we are with a new post of the “How do I do this” series! Have you ever found yourself dealing with a 1-hour long video where the only thing of interest happens for 5 seconds? As long as the file is sitting on a local drive, that’s usually not an issue. But what if you need to send the file to a colleague? Is it possible to trim only the relevant part without lowering the quality? Keep reading to find out how Amped Replay lets you do this quickly!

Use the “square brackets” buttons in Amped Replay‘s player bar to set the start and end of the range. Then, go to Export and choose Export Original Video as AVI. Done!

Compactness is definitely not among the merits of digital video. Depending on framerate, resolution, and compression, a single minute of video can eat up hundreds of MBs. When everything is stored locally or accessible through a fast local area network, this could seem less than an issue. However, there are times when your video needs to travel or when it is appropriate to trim only the part of footage where the incident happens to avoid maintaining superfluous sensitive information.

Trimming a video is something any video editing software lets you do easily. However, in most cases, you’ll go through a recompression process: pixels will be decoded and re-encoded after the trim, thus leading to a quality loss. You may try and reduce the amount of compression, but then find that your clip is actually larger in file size than the original! Recompression (known as transcoding) is therefore something you definitely want to avoid – unless you think changing the encoding algorithm is useful for the sake of better compatibility, as we discussed two weeks ago.

When dealing with video for forensic purposes, preserving the best possible evidence is of paramount importance. Failing in doing so may invalidate your whole work, especially since lawyers are getting tech-savvy, and they’ll question everything you did.

Now, we know there are cases where carrying out enhancement and analysis on the originally recorded pixels is unfeasible; in such cases, you are allowed to pick up the pixels in some other way, trying to minimize the quality loss. But if all you need to do is trimming part of the video, then that’s not a good reason for losing pixel originality!

Luckily, Amped Replay has you covered! Let’s say we have this beefy 30 minutes video (54k frames), which is 1.5GBs large, and we need only from frame 11.400 to frame 12.300.

Using the mouse, we drag the player head close to frame 11.400, then we can navigate frame by frame using the dedicated buttons or hitting the J (previous frame) and L (next frame) shortcuts. Once we reached frame 11.400, we click the Start range button:

Then, we move to frame 12.300 and click the End range button.

As you can see, after this process, the player bar shows the selected range in light gray, while the excluded range is marked in dark gray. You can toggle the player bar to display only the narrowed range or the full video by clicking on the button between the Start range and End range. If you instead want to clear a start or end range assignment, just click again on the same start (or end) range button.

Once you’ve selected the part you want to extract, it’s time to move to the Export tab. If we care about preserving the original pixels, we’ll go for the Export Original Video as AVI button. If instead, we prefer transcoding the video to H.264 and put it in an MP4 container (which means: extremely wide compatibility), we’ll rather choose the Export Original Video as MP4.

What’s the difference? When you use Export Original Video as AVI, Replay will do what we call a “lossless trim”: it will extract the frames you wanted without re-encoding them. To do so, we need that the exported range starts with an intra-coded frame (keyframe). If your selection does not start from a keyframe, Replay will automatically include some extra frames at the beginning, going backward until a keyframe is found. Let’s now load the exported video and see what we have:

First of all, it’s just 13 MBs! Instead of the expected 900 frames, you see we have 1122 frames. This is expected for the reasons explained above: you can’t do a lossless trim starting from an arbitrary frame, it must be a keyframe, so Replay included some extra frames at the beginning. If you’re trimming to remove disturbing content, remember to check that the trimmed video is actually OK. This way of exporting is extremely fast since it only copies data without any pixel processing. The most important issue here is that the visual information within your range of selected frames has retained integrity. The pixels have not changed from the original video file to the trimmed clip.

Conversely, when you use Export Original Video as MP4, the video gets transcoded, which means you’ll get exactly the desired range, but you’ll necessarily end up with (slightly) different pixel values. As we can see below, the so-exported video has exactly 900 frames, and the size is also slightly decreased.

That’s all for today! We hope you’ve found this issue of the “Amped Replay Tutorials: How do I do this?” series interesting and useful! Stay tuned and don’t miss the next ones. You can also follow us on LinkedIn, YouTube, Twitter, and Facebook: we’ll post a link to every new tutorial so you won’t miss any!