Render QuickTime Alpha Transparency in Kdenlive

Exporting videos with transparent backgrounds is essential for creating motion graphics, lower thirds, and video overlays. This article provides a direct, step-by-step guide on how to configure Kdenlive’s render settings to export video sequences with an alpha channel using the QuickTime Animation (qtrle) codec.

Step 1: Prepare Your Timeline

Before rendering, ensure that your timeline contains transparency. Any area without a background video or color clip will default to transparent. If you are using green screen footage, ensure you have applied the “Chromakey” effect to remove the background, leaving only your subject on the transparent timeline.

Step 2: Open the Render Widget

Click on the Render button in the top toolbar, or press Ctrl + Enter (Cmd + Enter on macOS) to open the Render dialog box.

Step 3: Create a Custom Render Profile

Kdenlive does not always include a default QuickTime Animation preset with alpha support. You must create a custom profile:

  1. Click the Create New Profile button (the small page icon with a plus sign) in the top right of the Render dialog.
  2. In the Profile Name field, enter a recognizable name, such as QuickTime Animation Alpha.
  3. Set the Group to Alpha Channel or User Defined.
  4. Set the Extension to mov.
  5. In the Parameters box, enter the following configuration line: f=mov vcodec=qtrle pix_fmt=rgba acodec=pcm_s16le
  6. Click OK to save the profile.

Step 4: Configure and Export

  1. Select your newly created QuickTime Animation Alpha profile from the list.
  2. Choose your destination folder and name your output file in the Output file field.
  3. Ensure the Render Full Project option is selected (or select Selected Zone if you only want to export a portion of your timeline).
  4. Click the Render to File button at the bottom of the window.

Kdenlive will now process and export your video. The resulting .mov file will contain a fully functional alpha channel, ready to be imported into any video editing or compositing software with its transparency preserved.