ULID-based Asset Storage Pattern

Use ULID keys in R2 and track all asset metadata in video_assets.

Key Pattern

Store objects at bucket root:

{ULID}.{ext}

This keeps paths flat, sortable enough for operations, and globally unique.

DB Record Shape

For each asset row:

• video_id
• asset_type (for example slide_image, slide_audio, rendered_video, highlight_video, thumbnail_image, prompt assets)
• asset_index (stable ordering)
• r2_key
• public_url
• mime_type
• file_size
• metadata JSON

Practical Rules

• Write metadata required by downstream stages (dimensions, durationMs, slideIndex, etc).
• Regenerate stage outputs by deleting old rows/assets for that stage before inserting fresh outputs.
• Use typed asset categories rather than overloading one generic type.