I have an OSS framework for this: https://github.com/scosman/videowright

- Voiceovers: aligns animations to the voiceover, can generate voiceover with elevenlabs, or will transcribe and timestamp a real voiceover

- can reorder scenes both in code, and using ffmpeg for audio.

- interactive controls during authoring, can ask for micro edits or re-builds

- MP4 export/encoder

- Generates the video with agent of your choice (obviously)