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The Sound of Silence: Learn How to Redact Audio in Amped FIVE

Reading time: 3 min

how to redact audio in amped five

Dear Tip Tuesday maniacs welcome to this week’s tip. We’re receiving a lot of positive feedback from users who tried the latest Amped FIVE release! Thank you so much for finding the time to send us your opinion. The new audio support is definitely the most welcomed improvement. So, on the wave of that, we’re dedicating this week’s tip to show how you can redact audio in Amped FIVE, with a walk-through example to try this new feature on!

In last week’s tip, we saw how to view and navigate the audio track in the new Amped FIVE Player panel. Today, we focus on audio redaction. Let’s work with an example (you can download the original file by clicking on the button below).

If you managed to download and watch it with audio, you may have noticed there’s a person’s name mentioned at time 00:19. We need to redact that while maintaining the rest of the audio signal.

Let’s go to the Presentation filter category and click on Audio Redaction:

audio redaction

You’ll see the filter appear in the chain and the Filter Settings panel showing its configuration parameters:

audio redaction

The Redaction Type lets you decide what kind of signal you want to use in place of the original audio. You can choose Silence or a Sinusoid at three different frequencies. In simple terms, it translates to “three different tones of BEEP” (higher frequency means more acute sound).

This image has an empty alt attribute; its file name is image-28.png

The Redaction Volume does not really need any explanation. Although, the Fade Length lets you set a time interval. Meanwhile, the redaction sound fades in and out at the beginning and termination of the redacted range.

“Okay, but… how do we select the part to be redacted!?”, I hear you say. Oh, that’s the easiest part! You simply need to hold the ALT key, click at the beginning of the range and drag until the end. While you drag, you’ll see the selected range track gets highlighted by a dark-blue rectangle. The range limits get written in the Redacted Interval panel.

redact audio in amped five

You can adjust an already selected range by holding the ALT key and dragging its borders. You can also move the selection by holding ALT, clicking into the blue rectangle and dragging it left or right.

Remember that by holding the CTRL key and rolling the mouse wheel you can zoom in/out horizontally (i.e., in time). E.g., in our example, inspecting the waveform closely allows you to redact the name of the person but not the “Mr.” spelled before. You may want to keep it in order to make it clear that the driver’s name was mentioned in the original video.

redacted audio

Notice that, while you can set multiple ranges in a single instance of the Audio Redaction filter, all the ranges will have the same redaction type, volume and fade settings. If you want to use different settings for different ranges (e.g., use Silence to cover a certain part and Beep to cover another part), you just need to cascade two Audio Redaction filters and configure each one as you wish.

redact audio in amped five


 Marco Fontani

Marco Fontani is the Forensics Director at Amped Software, a software company developing image and video forensic solutions for law enforcement agencies worldwide. He earned his MSc in Computer Engineering in 2010 and his Ph.D. in Information Engineering in 2014. His research focused on image watermarking and multimedia forensics. He participated in several research projects funded by the EU and EOARD, and authored/co-authored over 30 journal and conference proceedings papers. He has experience in delivering training to law enforcement and provided expert witness testimony on several forensic cases involving digital images and videos. He is a former member of the IEEE Information Forensics and Security Technical Committee, and he actively contributed to the development of ENFSI’s Best Practice Manual for Image Authentication.

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