SaaS Sports Video Editing Tool

I need an online application that lets me upload an MP4 of a training session, drop simple visual cues on top of it, and replay the clip with those cues burned in. The core flow is straightforward:

• Secure log-in screen that separates Admin, Editor, and Viewer roles.
• MP4 upload to the cloud, with progress feedback.
• A browser-based canvas where I can:
 – draw arrows,
 – highlight pressure points, and
 – set slow-motion ranges.
• One-click save so the annotated version is instantly available for replay from any device, preserving the original in case I need to start over.

An Admin must be able to add or remove users and assign them Editor or Viewer rights; Viewers should only be able to watch the finished video, not alter it.

I am open on the tech stack—React, Vue, Node, Django, FFmpeg, or any combination you are comfortable with—as long as the final product is fast, intuitive, and ready to scale as a SaaS. Please include an outline of your proposed architecture, a rough timeline to MVP, and a short demo of similar work if you have it.