In this video, I'm going to show you how to perform a screen replacement using the Planar Tracker in Fusion, a part of DaVinci Resolve. It's common for screens to be left blank during production, with their contents being added later in post. This might be because the assets being used on the screen haven't been built yet, or perhaps because compositing them in post can yield better image quality. The media we're using today is an over-the-shoulder handheld shot. I'm planning to composite a computer screen with a video clip playing in a window. Please note, I do have color management enabled, and have already configured the input color spaces of the clips that I am working with. To begin working on the clip, select it in the edit page, and then head to the Fusion page. The clip has now been automatically converted into a Fusion composition. Please note, Fusion is powerful and complex. This lesson assumes at least a rudimentary understanding of the way that this page works. Now, if this shot had been locked off on a tripod, screen replacement would be as simple as a corner pin. It's not its handheld, but thankfully production have put tracking markers on the screen. The best tool for tracking flat surfaces like this is a Planar Tracker. Open effects, search Planar, and drag the effect down onto your node tree. If I drop it directly on the connection between media in and media out, it will be automatically connected to my node tree. With the Planar Tracker node selected, in your viewer, draw a rectangle around the tracking points on the screen. Click for each point that you want to create, and don't forget to connect your last point back to where you started. As you can see, this shape does not have to match the screen. The only important thing is that it contains the features I am tracking. Because I've got the Planar Tracker selected, its controls are available in the Inspector. In the Inspector, hit set. This configures the frame from which the Planar Track will be analysed. It's worth noting that your reference frame doesn't have to be at the beginning of the clip. As you can see, mine's in the middle. But it will make it slightly more complicated because I can't track through the entire shot in one go. I'll track forward from my reference point, return to my reference point, and then track back to the beginning of the clip. But it's perfectly doable. I'll start by tracking forwards. You'll notice the Planar Tracker has created a cloud of tracking points. Trackers rely on unique and contrasty features in your image. A blank screen would be impossible to track. These shapes are excellent for tracking because they have so many corners. Now that my forward track is completed, I'll go back to my reference frame by hitting go, and then track the remainder of the clip in reverse. Now my track is complete, I can change the operation mode of this node from track to corner pin. Match the shape that appears in your viewer to the screen. Accuracy is really important, so make use of that zoom. To zoom in, use the drop down menu in the top left hand corner, or alternatively hold down on command or control and use your mouse wheel to zoom in. You can navigate around the viewer by holding down on your mouse wheel and dragging the mouse. As I move the playhead, you can see that the Planar Tracker is doing its job. That shape is pinned perfectly to the screen. Now we can add our screen replacement. From the media pool, grab the screen and kitchen clips. Drag them into your node window one by one. We can't see them in the viewer on our right, that's because they're not connected to our node tree. Firstly, let's do some housekeeping and name the nodes. To check which node is which, I can view them by dragging them into the left hand viewer. This of course is the kitchen, and the other one must be the screen graphic. I prepared this graphic earlier, it's a PNG with transparency where I want the video to be visible. I need to merge the screen graphic onto the kitchen video clip. That's done with a merge node. I could find that in the effects tab, but the easiest way to get one in your node tree is to drag the output of the screen node onto the output of the kitchen node. As you can see, it's automatically created a merge node and joined the screen and the kitchen nodes to it. The merge node takes two inputs and combines them into one. The kitchen node is connected to the background input and the screen node is connected to the foreground input. To view the results of that merge, drag the merge node into your left hand viewer. Hey, that's looking pretty good. I could centralize that video clip better with the player, I'd use a transform node for that, but it's looking pretty good as it is, so I'm not going to bother for now. The next job is to connect my brand new screen composition to my planar tracker. You'll notice one of the inputs is called corner pin. You can see the names when you hover over them with your mouse. To connect these nodes, I'll drag the output of my merge node onto the corner pin input of the planar tracker. There you go, look at that, it's pretty good, but there are some things that I can do to improve it. Firstly, it's too saturated. I'll apply a color corrector node between the merge node and planar tracker node and reduce the saturation and gain to match it better. Secondly, it's a little bit too sharp. I'm going to fix that with a blur node. Now, if you're getting tired of going up to the effects tab to find the effects that you want to apply to your node tree, good news, there's a quicker way of doing it. We'll close the effects tab, that's better, we've got back some of our precious screen space and on your keyboard hit shift space bar. I'll search for the blur effect, there it is, and you can see it's selected. When I click add, not only will this effect be added to my node tree, but because I've got the color corrector node already selected, it will automatically insert it in between that and the planar tracker node. Excellent, the default settings are fine. Third problem, as still images don't have video noise, the absence of moving grain in this portion of the image is really going to distract viewers. A quick fix is to add a grain node and dial it in to match the background plate. And fourth, we need to enable motion blur in the planar tracker node. You'll find that by selecting the planar tracker node and going to the settings tab. Increasing quality will give better motion blur, but at the cost of render time. Now when the camera moves quickly and produces motion blur, our screen replacement will also show motion blur. There's more that we could do to make the screen replacement more realistic, for example adding reflections to the screen. Maybe we'll cover these and other techniques in a future tutorial. In the meantime, let's head to the edit page. As I have smart render cache turned on, this fusion clip has been automatically marked for caching. You can tell that because there's a red line above it. Once this clip is cached, it will turn blue and then it's possible to experience smooth playback even on computers with limited processing power. I hope you found the video helpful. If this is your first time using fusion, welcome! You're gonna love it. Please give the video a like, make sure you subscribe so you don't miss future tutorials, and thanks for watching!
