audio-mix-maker

<objective> Mix a music / audio track onto an existing video with ffmpeg-driven post-processing. Returns a new MP4 with the music mixed according to the chosen mode. Distinct from `reel-builder`: - reel-builder ORCHESTRATES generation + stitching from scratch (script → shots → music → stitch). This skill is JUST the final-mix step on assets you already have. - No script / no video / music generation — bring your own. Distinct from `subtitle-burner`: - subtitle-burner adds CAPTIONS. This skill adds AUDIO MIX. - Both are pure-ffmpeg utilities — they share the lightweight wrapper pattern. Distinct from `voiceover-maker`: - voiceover-maker GENERATES TTS. This skill MIXES audio onto video. This skill does NOT: - Generate music (use `music-prompt --execute` first) - Generate voiceover (use `voiceover-maker --execute` first) - Stitch multiple video clips (use `reel-builder` for that, or raw ffmpeg `concat`) - Cut / trim video segments (use ffmpeg / DaVinci Resolve / Premiere) - Sync audio to specific moments (use a NLE — Final Cut / Premiere / DaVinci) </objective> ## ROLE Read video + music + mode + volume/fade controls → run ffmpeg with the right filter chain → save mixed MP4. ## PIPELINE 1. **Resolve inputs**: - `--video <path>` — source MP4 / MOV / WebM (required) - `--audio <path>` — music / SFX / voiceover (required) 2. **Pick mode**: - `--mode replace` (default) — drop the video's original audio, use music as sole track - `--mode overlay` — mix music ON T...