Remove Unwanted Shot Features with Resolve 15’s Patch Replacer
Do you need to remove some unwanted elements from your footage? DaVinci Resolve 15’s Patch Replacer has got the fix you need.
Resolve has always offered tools that can help you remove unwanted features from your images, but with Resolve 15, these tools have been streamlined, and new additions are now available. Let’s have a look at how you can patch an unwanted element from your image with the Patch Replacer.
In the shot below, the edge of the slider is visible.
The slider is only in the frame for a few seconds, and I’m sure we could use the 2:35:1 output blanking or slightly increase the scale to hide the slider, but they are cheap fixes and not always viable solutions. We want to remove this error. We could do this by using a power window to create a digital paint job; however, now in 15, the patch replacer plugin can do the same job more efficiently. The patch replacer is essentially Resolve’s answer to the clone tool in Photoshop. It clones, either adaptively or directly, a patch from the source to the target.
If you watched the Blackmagic Design Resolve 15 announcement at NAB, the host of the video also demonstrates that this tool can duplicate onscreen features, so we don’t have to use this tool solely to patch errors; there are creative elements that we can also use.
To get started, first we need to head to the color page, find the clip that needs the fix, create a new node, and finally apply the Patch Replacer from the Resolve Revival category. This section of the Resolve Effects library is where you will find the tools to revive or fix your footage.
When you first add the Patch Replacer onto a node, you’ll see these two ellipses: the source patch and the target patch. If we relate back to Photoshop’s clone tool, this works in a very similar fashion. You place the target ellipse (which can also be changed to a square or an alpha channel) over the area of the image that needs removal and the source patch over an appropriate space to clone.
Resolve, by default, uses an Adaptive Blend fill-in-method. This method uses pixel data from the source but will blend the edges of the target area with color and lighting data from the surrounding area of the target patch. The adaptive blend isn’t so much a direct clone but a blend of both to make a more organic-looking replacement. I find this method works great when patching over shrubbery or a tree line. Unlike a lot of tools used to repair errors, the patch replacer is relatively easy to use and can quickly become a one-stop solution. If you have a stationary shot with the mic slightly in the frame, simply drag the effect to a node and position the source and target regions. Mission accomplished.
However, there are going to be situations when the default settings aren’t appropriate, and you will need to change them.
First, we have the fill-in method. You can change this from adaptive to clone or to fast mask. The clone option literally clones the source to the target. While at first, the harsh edge makes the patch replacement quite distinct . . .
. . . with an increase in the Blur Sharp Edges slider, which essentially feathers the target patch, you may find it sometimes produces a better result than the adaptive fill (depending on the shapes and colors of the original image.
Then we have the Fast Mask. This eliminates the source patch and instead does a quick pixel blend from neighboring pixels. Generally, this will only ever be useful for minute errors such as a drop of water on the lens, but even then, the results will vary.
The other adjustable settings are fundamental parameters such as global blend, position, and size. While you can adjust the size of the source and target patch on the preview monitor, you may get more precise results using slider or numerical input in the inspector.
This is the Patch Replacer. Based on the image, it seems like a simple tool to use, and to some extent it is. I’m sure that with just a small tweak of the settings, the most inexperienced Resolve users can remove most foreign objects within a frame. The difficulty in using the effect, however, comes into play when the shot is moving.
Once you have positioned and corrected the patch, it then needs to be tracked so it follows with the camera movement. It’s only recently with the addition of Fusion into Resolve that I’ve started doing these sort of fixes in Resolve — and not taking the media clip to an additional program like After Effects. With that, there were a few hurdles in understanding how the FX tracking works in Resolve.
With the Patch Replacement complete, open the tracking window (found in the middle of the group controls) and select FX from the drop-down menu on the top-right of the panel. As with the stabilization and power window tracking, you hit one button, and the task is complete. Since Resolve has a world-class tracking system, there’s little need for additional user input. However, that isn’t the case for FX tracking.
If I were to hit the track forward button, I would see the following text: “No live features to track.”
This is because we haven’t manually added a track point — there’s nothing to track. To do so, you need to add a tracker by hitting the add tracker point button (one that I initially couldn’t find for quite some time despite it being glaringly obvious).
You want to add tracking points to very visible elements that surround the area that needs a patch. In a perfect situation, you would want to add tracking points to the equipment in the shot; however, in this specific example, the slider is out of focus and would make for poor tracking. The white and red strips of paint on the other hand are great examples of visible elements to track. When you have added the tracking points, hit track forward (and track backward if needed), and your patch replacement should remain in place when the clip plays forward.
Like the clone tool in Photoshop, there are limitations to the Patch Replacer. It only replaces patches, if the majority of your frame consists of visual errors, it might take something a little stronger than Resolve 15 to correct that.
Lewis McGregor is a certified DaVinci Resolve trainer.
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