99 lines
4.9 KiB
Markdown
99 lines
4.9 KiB
Markdown
# Video Editing Service — local cinematic highlight generator
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Turn a single source video into a cinematic highlight **entirely with local, offline models**: it selects the
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moment, cuts a story-structured montage, generates the music/SFX/voiceover, applies a cinematic grade, and
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masters the audio — no external AI services, no runtime downloads.
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> **Status:** a working, source-adaptive **proof of concept**. The cinematic quality ruleset (R1–R9, below) is
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> complete and content-agnostic. It is **not yet production-hardened** (no auth on the render endpoint,
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> no containers/PostgreSQL/no-egress certification, and the local models are non-commercially licensed — see
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> [Limitations](#limitations)). Do not deploy as-is.
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## What it does
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For one source clip the single-source highlight pipeline runs, fully offline:
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```
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ingest ─► analyze (ffprobe, scenes, audio, frames)
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─► candidates + category
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─► DIRECTOR (auto):
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Tier 1 measure motion (YDIF) + audio (RMS) ─► story-structured shot list
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Tier 2 local VLM (moondream2) captions beats ─► semantic payoff selection + overlay + music mood
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─► generate assets (Piper voice · MusicGen music · AudioLDM2 SFX)
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─► render (portrait/landscape-aware, exposure-normalized, push-in, crossfades, slow-mo ramp,
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bold overlay, ducked source under a swelling score)
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─► master loudness ─► QA probes ─► final.mp4
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```
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Rendering is gated: it stays off by default and requires an explicit approval flag per project.
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## Cinematic quality rules (R1–R9)
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Every rule is **source-adaptive** — it measures the source and adapts, rather than hard-coding constants.
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Full detail in [`docs/cinematic-quality-rules.md`](docs/cinematic-quality-rules.md).
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| # | Rule | Measure → adapt |
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|---|---|---|
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| R1 | Exposure | frame luma → normalize; grade never crushes the subject |
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| R2 | Orientation | source rotation → portrait/landscape output, no distortion |
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| R3 | Audio balance + loudness | score leads, source ducked; measured loudness corrected to −16 LUFS |
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| R4 | Duration | any length, story-driven |
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| R5 | Motion push-in | per-shot motion (YDIF) → adaptive in-shot `zoompan` |
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| R6 | Transitions | cross-dissolves between beats + ease into slow-motion |
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| R7 | Overlays | bold, outlined, animated entrance |
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| R8 | Music dynamics | volume swell builds into the payoff |
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| R9 | Show the action | Tier-1 measured **+ Tier-2 VLM caption-driven** selection |
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## Build & test
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Requires **JDK 21** and **ffmpeg/ffprobe** on the PATH.
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```bash
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mvn -B verify # compile, run all tests, JaCoCo gate
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```
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CI (`.github/workflows/ci.yml`) runs this on every push.
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## Run the highlight pipeline (local PoC)
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The `localpoc` Spring profile wires the pipeline to pre-provisioned local model paths, isolates its
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input/output trees, keeps rendering disabled + approval-required, and never starts a network-capable
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bootstrap. The end-to-end command sequence (stage source → analyze → auto-direct → approve → render) is
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documented step-by-step in the operator runbook. Outputs land under
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`output/localpoc/highlight-projects/<project>/final.mp4`.
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Local models used (each with a provenance sidecar under `models/`):
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| Model | Role | License |
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|---|---|---|
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| Piper (`en_US-lessac-medium`) | voiceover | MIT / Blizzard dataset |
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| MusicGen small | music | **CC-BY-NC** |
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| AudioLDM2 | SFX | **CC-BY-NC-SA** |
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| moondream2 | Tier-2 vision director | Apache-2.0 |
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| YOLOv8n (optional CV) | visual analysis | **AGPL-3.0** |
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## Non-negotiable constraints
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- No automatic dependency/model downloads at runtime; models load offline from `models/` + the local cache.
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- No external AI services in the media path.
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- No unlicensed assets; no placeholder silence/tones passed off as generated audio (the pipeline fails closed).
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- No rendering without an explicit approval flag.
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## Limitations
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- **Licensing:** MusicGen (CC-BY-NC), AudioLDM2 (CC-BY-NC-SA) and YOLOv8 (AGPL) are **non-commercial/copyleft**.
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Commercial use requires swapping in commercially-licensed models/assets.
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- **Not production-hardened:** no Spring Security/authN, no container/K8s/deployment manifests, REST persistence
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defaults to in-memory, `POST /v1/edit-projects/{projectId}:render` has no approval gate, and no-egress
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operation is not yet certified.
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- **VLM quality:** on distant/small subjects the small local VLM is only weakly discriminative; a stronger
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model or closer framing improves Tier-2 selection.
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- A director can only cut what was filmed — it cannot show a moment the camera never captured.
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## Repository map
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- `src/main/java/org/example/videoclips/editing/` — highlight analysis, two-tier director, renderer, QA.
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- `tools/` — local model workers (`local_asset_worker.py`, `vision_caption.py`).
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- `src/main/resources/application-localpoc.yml` — the opt-in PoC profile.
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- `docs/` — the PoC plan, the cinematic quality rules, acceptance review.
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