In this tutorial, we'll take a look at one of the most common VFX techniques – screen replacement. Let's see how it's done in After Effects.
If you've ever tried to capture a screen with your video camera, you've probably encountered one of many possible problems. This includes a flickering image, exposure mismatches and banding – to name just a few. You can play the game by adjusting the shutter speed of your camera and adjusting the refresh rate. However, it is still difficult to achieve the perfect process. Let's look at a more versatile option today – screen replacement.
Don't have time to watch the video? Read the transcript below to learn the VFX technique at your own pace.
What is a screen replacement?
Screen replacement is a basic technique that gives VFX artists and video editors complete control over post-production. Regardless of whether it's a phone, a television, or a computer screen, the overall process is the same. Track the screen in your shot and use this tracking data to replace the screen with a separate clip or sequence.
Let's look at a simple but versatile method that allows you to maintain the natural reflections in the scene. We'll jump into Adobe After Effects and break it down step by step.
Step 1. Track the screen
I have taken a sample clip of myself looking at my phone with my mirror image clearly visible on the phone screen. I intentionally recorded this on a blank screen so that I can use the black color to easily isolate the reflection later. But first we follow the clip.
After Effects has a great point tracking system, but I prefer the planar tracker of the mocha effect. It's just more versatile when it comes to tracking screen swaps. And don't worry, Mocha AE is bundled with After Effects, so you've already installed it.
I take the first step Mocha AE Effect of Window> Effects & Preferences> Boris FX Mocha and drag it onto my clip. Now I can click on mocha Button in the Effect control Panel that starts the app. Do not be afraid if you are not familiar with the program. The Basics The work area makes work easier.
I choose an area to track about X-spline tool. I want to avoid unnecessary movements, e.g. B. my reflection in the middle of the phone screen. For this reason, I'm going to make a selection around the edges of the phone. I will also activate perspective by doing Track movement options Area. The forward / backward buttons are directly below. After the chase, the timeline turns blue.
When my track is finished, I choose Show planar surface, as well as Show planar grid. The flat surface is translated into corner points. So I'm going to use this tool to optimize the limits of screen usage. The grid serves as a reference and allows me to check the quality of my lane and the surface of the aircraft. Now you can see why it is a planar tracker.
As soon as I am satisfied with my results, I save and close mocha.
Step 2. Prepare the replacement clip
Next, I prepare my on-screen system. Since this is a vertical video, I have to prepare it properly. First, I bring my clip that I want to insert into my composition and select it Layer> Pre-ComposeMoving all attributes into the new composition. When applying the tracking data, the inserted element (this new precomposition) must match the resolution of the tracked clip (randomly UltraHD).
Since the phone is a vertical video, I need to resize my picture to make sure it fits on the screen. To do this, I dive into my Pre-Comp and compose my nested clip again. This last pre-comp must match my phone's resolution. When the Pre-Comp is open, I go to Composition> Composition SettingsThen manually enter my phone's vertical resolution, which is 1080 × 2340.
To ensure the organization, I rename my Pre-Comps to Insert screen and Screen insertion clips. Now I'm going to resize and position my clip in position Screen insertion clips comp accordingly. If I want to do animations, this is the pre-composition in which this will happen.
After Effects applies a when applying the tracking data Corner pin Effect by essentially adjusting my pre-comp function to the screen of my phone. That's why I'm going to grab them Screen insertion clips Pre-Comp within the Insert screen comp and select Layer> Transform> Fit to Comp. Good, gracious, I look good!
Step 3. Replace the screen
The insert is ready, so I navigate back to my Master-Comp and grab the original phone clip. By doing Effect control Panel, I'm going to open that Track data Menu in the Mocha AE Effect and click Create track data. A dialog box appears, showing me the layers I created in Mocha. Since I have only created one, I use the Mobile phone screen track and click OK.
This will insert the title data into my clip and add corner pin keyframes. I export this data to mine Insert screen comp. Under Export optionsI will change the setting to Corner pen with motion blurand put that Layer export to my Insert screen comp. After applying the export, my insert is now tracked along with my phone.
Step 4. Isolate the reflection
Last but not least, I'll isolate the reflection. Since the reflection of my original clip is on a blank black screen, I can use basic blending modes such as: Brighten, add, or screen. If I'm in a hurry, I can quickly introduce reflection by using the blending mode of the Insert screen. But as I said, I want to isolate the reflection, which requires a few extra steps.
To do this, I duplicate both Original clip and the Insert screen and bring both layers up. I will rename the original duplicate reflection and the screen inserts duplicate Reflection mat. Now I'm just going to place it Reflection mat Level up and insert the track's matte column reflection Layer too alpha. This only isolates the screen of my original clip. Now I'm just going to set that reflection Mixing mode of the layer on Brighten, add or screen.
With reflection on my own level, I now have complete control. I can change that opacity, frame, and position Parameters to get the reflection exactly as I prefer.
What are you waiting for? It's time to replace these screens! When you're done, check out this additional After Effects bonus: