Understanding the Differences Between Amped FIVE or Amped Replay vs Consumer Video Players

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Dear friends welcome to this week’s tip! Today we take inspiration from a question that we receive from time to time from our users. It basically goes like this: “How come consumer video players like VLC sometimes appear to play the video better than Amped FIVE or Amped Replay?”. If you’re curious about the answer… just keep reading!

Right from its beginnings, Amped has been pursuing a crystal clear mission: becoming the one-stop-shop for any needs related to image and video analysis and enhancement. The company motto, Justice Through Science, helps to clarify our mission to deliver products that are based on the scientific method. Now, acting scientifically requires you to:

  1. be aware of what you do,
  2. give the reasons for what you do, and
  3. use validated tools.

How does all of this relate to the “VLC” question? Let’s see it with some examples!

Scientific Tools Require Scientific Methods

First and foremost: resampling. Imagine you’re given a surveillance video that happens to be playable with VLC. You then notice that VLC opens up in a small window… that’s because the video resolution is very low.

Screenshot of VLC Media Player displaying a nighttime surveillance video titled "backyard.avi" with infrared footage showing a fenced backyard area. The timestamp on the video reads "2020 Apr 21, 23:17:44". The player controls are visible, including the play, record, and volume buttons, and the progress bar indicates 2 seconds into a 4-second video clip. The interface is in Italian, showing menu options like Media, Riproduzione, Audio, and Strumenti.

One is naturally tempted to drag VLC’s window corner to enlarge the player… and it works! The video actually gets as big as your screen allows.

Full-screen view of VLC Media Player displaying infrared nighttime surveillance footage titled "backyard.avi". The video shows a fenced backyard with a lawn, shrubs, and a building wall on the left side. The timestamp in the top right corner reads "2020 Apr 21 23:17:44". VLC interface elements are visible at the bottom, including play controls and a progress bar indicating the video is at 2 seconds of a 4-second duration.

But how did that happen? As a consumer video player, VLC simply aims to provide a pleasant image. It will enlarge your video using interpolation, which means, it will compute new pixel values from the actual pixels. There’s nothing wrong with resampling, but if you’re doing video forensics, it must be done intentionally. You must save all the information about which algorithm you used and with which parameters.

Moreover, resampling should be placed at a certain point in the processing chain, which the analyst should accurately choose. For this reason, Amped FIVE and Amped Replay will not compute new pixel values when you enlarge the video with the magnifier (or scroll with the mouse wheel). They will simply make current pixels larger (so-called “nearest neighbor” interpolation) so that you can fully understand the amount of information that is present in your evidence. When you decide that interpolation is needed, you’ll readily find it in the Resize and Smart Resize filters under the Edit category.

Metadata Can Be Misleading

Let’s now move to another case: we’re working on a .MOV video file. Once opened with VLC, it shows this urban scene, with people walking on a street.

VLC Media Player displaying a paused video titled "D25_V_outdoor_still.mov" showing an urban outdoor scene during daylight. The view captures a street between two modern buildings, with a textured pavement in the foreground. Two men are walking along the sidewalk next to the right-hand building, and multiple bicycles are parked nearby. A "no through road" sign is visible beside the walkway.

“Hooray!”, we say. It’s decoded by VLC so this will be an easy one for FIVE! We thus drag the video into Amped FIVE, and we’re presented with this:

Screenshot of the Amped FIVE software interface showing a loaded video frame from the file “D25_V_outdoor_still.mov”. The displayed frame appears upside down and shows an urban street scene between two buildings with pedestrians and a dead-end traffic sign. The interface highlights various forensic tools and panels including “Filters,” “Tools,” “History,” and “Player,” with frame number 1215 selected on the timeline. The Video Loader panel is active on the right side with “FFMS with Audio” set as the video engine.

It’s upside down! Why is that? Well, it’s easy: the guy who took the video was holding the camera upside down, so the video was recorded on the camera sensor upside down as well. But the camera was aware that it was being held in the “wrong” position, so it simply added to the video container, information about how to process the video and make it play “better”. This is easily spotted using the Advanced File Info tool in Amped FIVE:

Screenshot of the MediaInfo tab under "Advanced File Info" displaying detailed metadata for a video file using Amped FIVE software. The metadata includes codec information (AVC, High@L4.1), bit rate (10.5 Mb/s), resolution (1920x1080), frame rate (29.970 FPS variable), and chroma subsampling (4:2:0). A red arrow highlights the "Rotation: 180°" field, indicating the video is stored upside down.

Now, when VLC reads the video, it will take that “suggestion” into account and automatically rotate the video. Amped FIVE (or Amped Replay) will instead show pixels the way they are actually encoded. They let the user make a decision about whether they should be rotated or not.

Now, you may be wondering: “Okay, but why don’t Amped products do what the container tells it to do”? There are two reasons:

  1. Amped products prioritize forensic soundness, while VLC and consumer players (understandably) prioritize a “click and watch” approach. We believe forensic software should not make decisions in place of the analyst, as it could get something wrong or it could add a processing step of which the analyst is not aware, and this is not good.
  2. If you know video containers, you also know you shouldn’t trust them so much!

Let us show you what we mean with point 2, with another example. We’re given another video, this time coming from a CCTV system with analog cameras. (Somewhat surprisingly) we see VLC can play it, so we happily launch it:

Screenshot of a VLC Media Player window showing a paused CCTV video titled “FullHD_60P.mp4_PAL_IL_CCTV.mp4”. The video frame displays a busy urban intersection with cars, a red and white bus, pedestrians, and the Haigh's Chocolates store. The timestamp overlay in the top left corner reads “06-09-1997 12:43:29:11”. The playback bar shows the video is at 00:17 seconds of a short clip.

Let’s look at how it appears in Amped FIVE:

Screenshot of Amped FIVE software interface displaying a paused CCTV video frame from "FullHD_60P.mp4_PAL_IL_CCTV.mp4". The frame shows a busy urban street with a red and white city bus, a white car, and pedestrians crossing near a historic building labeled "Haigh's Chocolates". A timestamp overlay at the top left reads “06-09-1997 12:43:29:11”.

We promptly notice a first, big difference: in Amped FIVE the vehicles show the typical interlacing artifact, which was not visible in VLC.

Close-up of a blurred and pixelated video frame showing motion blur and compression artifacts. A red and white city bus and a white SUV are captured mid-motion in front of a storefront displaying the sign "HAIGH'S CHOCOLATES". The vehicles appear distorted with visible interlacing lines and ghosting effects, indicative of low video quality or rapid movement.

Full Analyst Control vs Hidden Automation

That’s because VLC, by default, automatically deinterlace videos when they need it. But it’s done in silence, so if tomorrow you’re asked or challenged about which deinterlacing algorithm you used… what will you say? You maybe even don’t know that you deinterlaced, because the software did it without any warning!

In Amped FIVE, it’s just a matter of firing up the Deinterlace filter: with just one click, you get full control of the deinterlacing algorithm to use (the default one is normally OK), and full documentation and repeatability. I wouldn’t trade in these two things for one click. But there’s more than that. You may have noticed that this video has black bands on the vertical sides. If we draw a rectangle around them, we’ll see they’re both 576 high (as the whole frame) and 8 pixels wide.

Screenshot of the "Tools (Selector)" panel in Amped FIVE software, showing options for manual region selection with adjustable coordinates (x, y), width (w) set at 8, and height (h) set at 576. The panel includes selection tools like rectangle, ellipse, and freehand, with buttons for "Select All," "Deselect," and "Zoom." The interface allows precise control over selection dimensions for forensic image or video analysis.

No image was ever recorded there, so the actual samples’ width is 720 – (8 x 2) = 704. Now, if we take a look at the container, we’ll notice it has information about how it was digitized, the Sample Aspect Ratio, which is 12:11 (if you want to know more, take a look here).

Screenshot of the Summary tab under "Advanced File Info" window in Amped FIVE video analysis software displaying metadata for a file named "FullHD_60P.mp4_PAL_IL_CCTV.mp4". Details include resolution (720x576 pixels), codec (h264), frame rate (25 FPS), duration (00:00:18.480), and no audio or subtitle streams. The display also lists various aspect ratios (SAR, DAR, PAR), video type, format, and color range as "Limited".

Let’s put this two information together: 704 x 12 = 8443 samples in width and 576 x 11 = 6336 samples in height. And if we compute the ratio, we have 8443/6336 = 4/3, which is the standard PAL aspect ratio. And so? If we want to display the video correctly, we need to deinterlace it, remove the two bars on the sides using the Crop tool, and finally use the Aspect Ratio tool, set to 4:3.

Screenshot of Amped FIVE software displaying a video frame of a city street intersection with a red and white bus passing by. The interface shows active filters including Video Loader, Deinterlace, Crop, and Aspect Ratio set to 4:3. The timestamp "06-09-1997 12:43:12:00" is overlaid on the video.

A normal video player doesn’t care at all about the black bars on the sides. It will just read the Display Aspect Ratio from the container and stretch the video, in this case incorrectly.

Final Note

We could continue with more examples: some video players will “automatically” deblock or filter videos to improve their appearance, or perhaps they will silently retain the image filtering settings that you used on Monday when you reopen the software on Friday to work on a different video (e.g., VLC works this way). It’s nothing serious if you’re watching a movie, but it can ruin someone’s life if you’re doing video forensics.

We hope this tip explained the reasons why we tend to not automate too much in our products. We want the user to be in control, and we offer our training to get them ready to make use of such control. Something consumer video players simply don’t provide.

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