Is there any plan to support webm in addVideo() API?

### Is there an existing issue for this?

- [X] I have searched the existing issues

### What's missing?

I would like to add a video to the current page using the addVideo() API,
but currently the addVideo API does not support the webm format.
To add a video to the current page, I need to create an mp4 file with the h.264 codec and add it using addVideo.
I have two questions like as follows.
1. Is there any plan to support the webm format in addVideo()?
2. In order to create an mp4 file with the h.264 codec, I need to create an mp4 file using the h.264 codec in FFMPEG in the Addon.
Do I need to handle the h.264 license issue separately in each Addon, or is there a separate support plan in the Adobe Express Addon?

Start with the addVideo() API documentation and its current format limitations. Check whether webm support and H.264 licensing guidance are documented elsewhere; done means the support and licensing questions have a clear answer, with any planned work linked to the relevant API documentation or tracking issue.

Written by the indexing model from the issue text.