A common task for video editors and motion designers is to export a video in DaVinci Resolve with an alpha channel so that it can be used by a client or colleague. Typical examples for needing an alpha are when you want transparency for a title, lower third, or removing the green shots on a green screen.
In this tutorial, we look at creating transparency on the Edit and Fusion pages. If your footage already had an alpha built-in like Titles do, it’s just a matter of picking the correct settings on the Delivery page. Let’s dive in!
3 Ways Create Transparent Backgrounds
1. Create Transparency from the Color Page
In this example, we’ll be using the free fire clip. This clip doesn’t have an alpha and shows fire on a black background. We want to remove the black, so this clip can be exported and then placed on top of other footage in another app or Resolve. What we select is kept (the fire), and the black becomes transparent. As a note: white is opaque, gray is semi-transparent, black is transparent.
- With the Fire clip on the timeline, click on the Color page at the bottom of the interface.
- Right-click in the gray area of the Nodes, and click Add Alpha Output.
- Drag from the blue (alpha) output of the Node to the alpha output.
- We need to create transparency (drop out the black) by using a Luma Key. Click on the eyedropper (qualifier) to go into the Qualifier section.
- Select LUM from the pulldown to key just the brightness information.
- Click on the eyedropper, and drag across a range of fire to select as much as possible.
- Click the Highlight icon on and off to see your selection.
Generally, you would want to finesse the key, and the higher quality footage (10 bit vs 8 bit), the easier it is to get a clean key. But in this example, we are just looking at workflow.
2. Create Transparency from the Fusion Page
This time we will use Fusion and a luma key. We find that Fusion generally gives you better results quickly, as it is a motion graphics and compositing app inside of Resolve.
For this example, we’ll be using this free dust clip. This clip doesn’t have an alpha, the dust is mainly gray (semi-transparent) and white (opaque). Again, we’ll want to remove the black, so this clip can be exported or imported back in Resolve as a stand-alone clip with an alpha.
In Fusion, we will be working with Nodes, instead of layers like in Premiere Pro or After Effects. Each thing we want to do goes on its on a node. We are going to scale up the footage and remove the black with a luma key.
- With the dust clip selected in the timeline, click on the Fusion page a the bottom of the interface.
- MediaIn is the dust footage and MediaOut1 is the output. Rename the node’s Dust and Output by using the shortcut F2, or right-click and select Rename.
- Select the Dust (MediaIn1) and click on Transform in the toolbar to insert the Transform node between the Dust and the Output.
- With the Transform node selected, increase the Size in the Inspector until the black fills the frame.
- With the Transform node selected, press Shift + Spacebar and type Luma to bring up luma keyer, and click Add.
The luma keyer makes the background transparent, and the black is now a checkerboard.
3. Rendering with Alpha from the Delivery Page
The only tricky part of exporting an alpha is remembering to selecting Individual clips, as the Single clip option can’t output an alpha channel.
You’ll also need to pick a codec that supports alpha channels because most formats don’t support it. There are generally three codecs used for exporting alphas: ProRes 444 and 444XQ, GoPro Cineform RGB 16-bit, and multiple flavors of DNxHD. Just make sure the codec has the Export Alpha box and check it.
- Select the Delivery page.
- Click on the clip you want to export, then click on Individual clips.
- Name the export (for example, including alpha in the filename) and give it a location.
- Pick one of the alpha supported codecs (for example, Cineform RGB 16-bit).
- Check the Export Alpha box, then click the Add to Render Queue button and then Start Render.
Exporting a video clip with an alpha channel in DaVinci Resolve allows you to bring that rendered clip back into the program as a transparent asset, import into another NLE, or motion graphics app. We hope this tutorial helped you understand the various ways you can export with transparency. Now, all that’s left to do is to give it a try on your own!