FFmpeg + Next.js Developer — Automated Video Pipeline (Near Complete)

I'm building an automated video editing web app that takes certain uploaded clips and renders a finished MP4 matching the style of a CapCut-edited reference video. The core is already built and working. The stack: Next.js 14 (web app + API routes) Node.js FFmpeg pipeline (scripts/render.js) — extracts clips, applies xfade transitions, mixes music and SFX Remotion for browser preview OpenAI API for AI night shot generation What's working right now: FFmpeg pipeline runs end-to-end and produces out/final.mp4 13 clips extracted, stitched with xfade transitions, and audio mixed in Transition system built and mapped to CapCut reference timings What I need finished: Compare the rendered MP4 against the CapCut reference video and tune xfade transition types and durations until they match closely Build the upload → render → download flow in the web UI (user uploads labeled clips, hits render, gets MP4 back) Generalize the hardcoded clip filenames into a flexible template that works with any uploaded set of clips Light UI polish You will be handed: Full codebase with detailed comments CapCut reference video to compare against Working FFmpeg render script you can run immediately Clear list of remaining tasks Ideal candidate has shipped FFmpeg video pipelines before and is comfortable jumping into an existing Next.js codebase. This is a finishing job, not a ground-up build.