# Content sourcing — strict-PD neutral bases

For each scale, acquire a calm, neutral source clip from a **strict public-domain**
US-government source, verify the license, then run it through the pipeline.

| Scale  | Source                         | Where                              |
|--------|--------------------------------|------------------------------------|
| cosmos | NASA / Hubble / JWST           | https://images.nasa.gov/           |
| orbit  | NASA / ISS                     | https://images.nasa.gov/           |
| forest | NPS / USGS                     | https://www.nps.gov/ , https://www.usgs.gov/ |
| reef   | NOAA Ocean Exploration         | https://oceanexplorer.noaa.gov/    |
| abyss  | NOAA Ocean Exploration         | https://oceanexplorer.noaa.gov/    |

**License check (mandatory):** confirm the asset is US-gov PD (17 U.S.C. §105) or
explicitly CC0. "Free stock" (Pexels/Pixabay/etc.) is royalty-free but NOT public
domain — do not use. Record a `Provenance` (tools/pipeline/provenance.py) per clip.

**Run the pipeline** (replaces the placeholder bytes for a scale):

```bash
python -c "from tools.pipeline.run import process_clip; \
  process_clip('downloads/<scale>.mp4', 'simulator/sample_media/<scale>', \
  start=<in_s>, duration=<len_s>, overlap=<0.5..1.0>)"
```

This writes `simulator/sample_media/<scale>/base.mp4` (proxy) + `master.mp4`. Then
author the labels (Increment 2: the hybrid track pass + simulator author mode) or
hand-edit the annotation track for now (spec §4). The ring + manifest entry already
exist; `process_clip` only replaces the media bytes.