# Performance and budgets

The page manager accounts for decoders and tracked bytes across players. A host
may configure an explicit lower resource policy; there is no implicit
small-asset byte ceiling. A player reserves before allocation, publishes exact
category ownership, and can enter fallback state when an actual or configured
resource boundary is reached. Hidden or reduced-motion players
release animation resources and leave host-owned fallback markup visible.

Authors own the cost of unit length, canvas/rendition dimensions, and bitrate.
Use authored restart runways and measure the real target devices.
The runtime never downscales or shortens a valid asset to fit. `getDiagnostics()` is
bounded and suitable for support logs, but verbose tracing, screenshots,
synchronous readback, and devtools perturb timing benchmarks.

Normal playback configures the selected decoder and fills the six-frame live
presentation ring before revealing frame zero. It does not run the exhaustive
all-routes decoder rehearsal during page startup. `runAllRoutesReadiness()` and
the certification application retain that full proof for an explicit,
dedicated development or CI candidate; it must not run in the background on a
live candidate because it owns decoder generations and probe presentation.

CI performance comparisons are advisory. A named scheduling certificate
requires at least 300 post-warm-up outputs at 1.5× authored real time plus exact
deadline and boundary rules. Heap, RSS, GPU-process memory, and energy are
observational; explicit ownership counters are the leak gate.

## JavaScript delivery gates

The original design target put the complete element, player, and worker below
75 KiB gzip. The implementation did not meet that monolithic target, so it is
recorded as a miss and is not presented as a release pass. The accepted gates
measure the costs users actually encounter at distinct loading boundaries:

- the source-free element bootstrap's complete static import closure is
  strictly below 75 KiB gzip;
- the complete loaded element/player graph, including bootstrap and its one
  lazy runtime closure, is at most 250 KiB gzip; and
- the self-contained packaged decoder worker is at most 20 KiB gzip.

`scripts/performance/measure-m8-bundles.mjs` builds production ESM with pinned
Vite 8.1.4/Oxc and gzip level 9, verifies one lazy runtime boundary and no
duplicated module ownership, then enforces all three limits. A preliminary
source-tree run on 2026-07-12 measured 17,708 bootstrap bytes, 226,721 loaded
graph bytes, and 15,829 worker bytes. The former combined interpretation would
be 242,550 bytes and therefore misses 75 KiB. These numbers are not frozen
package evidence; the exact candidate must be measured again and recorded
before a release claim.