Asset manifest
An asset manifest records source identity, variants, media type, dimensions, duration, bytes, digest, fallback relationships, and the route or scene that consumes them.
json
{
"id": "hero-fold",
"source": "media/fold-master.png",
"variants": [
{ "path": "media/fold.avif", "width": 1672, "bytes": 19746 },
{ "path": "media/fold.webp", "width": 1672, "bytes": 59306 }
]
}Reproducible profiles
- image
- AVIF/WebP variants, dimensions, quality, fit, and fallback
- video
- Codec, bitrate, dimensions, duration, poster, and reduced-data alternative
- font
- Subset, axes, preload policy, license, and fallback metrics
- 3D
- Geometry, textures, compression, renderer tier, and static fallback
Device budgets
Budgets are evaluated by route and capability tier. The first viewport, complete document, scene memory, and long-task behavior remain separate evidence instead of being collapsed into one marketing score.
Fallbacks are part of the design
Every optional 3D, video, or motion surface defines a meaningful static or lower-tier representation. Save-Data and reduced motion never produce a blank composition.