Dear Amped friends welcome to this week’s Tip! We hope you’ve already heard of the latest Amped Replay update, which rolled out a few weeks ago. One of the coolest new features is assisted tracking, which makes annotations in Amped Replay even more powerful and easy than they were before. This weeks’ tip comes directly from one of our developers: it helps to make assisted tracking work better in challenging situations, so don’t miss it and keep reading!
Being able to track annotations is a fundamental feature, and it was available in Amped Replay since the early versions. However, until the latest 18163 Update, you had to manually track the object of interest while it was moving. It was very simple to understand, but not always easy to do, especially for fast-moving objects. Let’s use this example (you’ll probably recognize it, we’ve used it in a past Tip Tuesday about tracking!)
You can download the original video at the link below:
Let’s say we need to redact the face of the walking subject. If you want to do it manually, you’ll probably need to slow down the playback speed, lowering the corresponding slider:
This way, the guy moves slower, so you can add a Hide annotation from the Annotate tab and more easily drag it over the face while playing the video.
However, it would be better to use the Assisted Tracking! Just draw the Hide annotation object over the guy’s face as he walks in, and then click on the Track button.
Notice that, to make things easier to understand in this tip, I’ve unchecked the Transparent option of the Hide annotation, so we see a red circle around the pixelation. Moreover, I recommend lowering the Strength slider to a very small value, so we see the pixels below the pixelation. We’ll have time to adjust the strength and border color once the tracking is done!
Now, as you probably know from our update blog post, when you activate tracking you get two dashed rectangles around the annotation object. The green rectangle tells which pixels should be used as a reference, which means: these pixels will be searched for in the next frame, and once they’re found, the displacement in position will be computed and applied to the annotation object as well so that it follows the object. The yellow rectangle, instead, tells the search region, that is, where pixels in the green rectangle should be searched for.
How do we configure the green and yellow rectangles? Well, intuitively, we’d adjust the green rectangle so that it contains the guy’s face, and we may set the yellow rectangle to extend to the right side only (because he walks towards the right).
Then we hold down the Track button with the mouse, and watch the Assisted Tracking work for us 🙂
Unfortunately, we see that the tracking works well until a certain point, then it gets “distracted” by the grids on the front of the building, which captures the attention of the tracking algorithm thus snatching the annotation object. Of course, we could simply go back to the last frame where tracking works and manually track the face for those frames. Once the building on the background is gone, we can restart using Assisted Tracking. That would certainly be OK, and it’s indeed great that you can seamlessly combine manual and assisted tracking for the same annotation.
But in this tip we’ll show you a pro-trick which will make Assisted Tracking work alone. The trick is that the green rectangle doesn’t have to include the annotation itself. It just has to include something that moves in the same way as the annotated object. Then, why don’t we track the guy’s jacket and trousers?
Let’s hold the Track button now!
It’s much better! Now tracking works well until the light pole, where, as expected, it gets disturbed by the occlusion. No problem, here we can really use the manual tracking to finish the job, as shown below:
And that’s it! Combining assisted and manual tracking is so easy and powerful with Amped Replay! We recommend that you download the original video (there’s a link at the beginning of the post) and try it yourself!