Use "slide videos", with cut at precise frames

First, thanks for this great tool.

I wanted to use some advanced animations built using some external softwares (like Blender or Manim) and use them inside a presentation. Blender/Manim will give me a video, and then I'll need to pause this video at appropriate frames. Of course, I could code myself something in javascript to do that using [VideoFrame.js](https://github.com/allensarkisyan/VideoFrame) ([eg](https://stackoverflow.com/questions/52074965/html5-video-stop-at-specific-frames-with-javascript)) , but I was wondering if it would be possible to integrate it somehow inside impress.js, so that I can use both "videos slides" and normal slides.

Ideally, the user would create a new frame where they could put the video, and somehow provide a list of frame stops to stop at. Then, pressing "next" would simply play the video until the next frame stop, and so on.

Do you think it's doable?

PS: if it could also be exported properly as PDF... It would be just awesome.

No impress.js file or test is named. Start by locating the presentation navigation entry point and reviewing how a slide could contain a video with configured frame stops; compare the approach with the linked VideoFrame.js example. Done should include next-step playback for video slides alongside normal slides, with the requested PDF export behavior assessed.

Written by the indexing model from the issue text.