nizima ACTION!! and Transparent Videos

Check transparent WebM support

As checked on September 11, 2026, the official nizima ACTION!! export manual says transparent WebM export is not supported. Exporting a WebM file does not necessarily preserve transparency.

MoniV cannot import a video without alpha metadata, even if the background looked transparent while editing. Check the official documentation, your current export screen, and the actual output.

• Official manual: How to Export
• Official Japanese export manual

What MoniV accepts

Once you have a suitable video, add a single file to the editor first. Confirm that it passes MoniV’s validation before preparing the rest of your animations.

• A VP9 WebM video with alpha metadata (alpha_mode=1).
• 1536×1536 or 3072×3072 at a constant 30 fps.
• A real WebM file, not another video format with a renamed extension.

When your video is ready

If you already have a transparent WebM video meeting these requirements, continue to the FFmpeg installation and video import steps. To display a character without making videos, you can also import a .moniv pack supplied by its creator.

• Install FFmpeg and add videos
• Import a .moniv character pack