#+TITLE: Music Config UI Remodel Prototype Benchmark
#+DATE: 2026-07-19

* Purpose

Measure the rasterization cost that matters for the proposed Emacs SVG port.
The interactive browser prototype proves behavior, but its DOM timings do not
predict librsvg cost.  These trials use =rsvg-convert= 2.62.3 against embedded
raster/SVG fixtures at the intended roughly 958×411 dock size.

The shell loop launched a fresh =rsvg-convert= process for each sample.  Process
startup is therefore included, making these results a conservative bound for an
in-process Emacs/librsvg update.

* Full instrument trial

- Fixture: concept 30 embedded as a 3.0 MiB data URI, plus live metadata,
  playlist rows, progress, VU needles, and volume segments.
- Output: 958×411.
- Duration: 60 seconds.
- Samples: 448.
- Mean: 134.074 ms.
- Median: 133.616 ms.
- 95th percentile: 139.822 ms.
- Range: 125.105–163.231 ms.
- Verdict: fail.  A full receiver rasterization cannot drive ten-Hz VU motion.

* Lower-deck tile trial

- Fixture: the opaque lower control deck exported at its 585×226 display size
  as JPEG quality 88, embedded as a 52 KiB data URI, plus two dynamic needles
  and twenty-one dynamic volume segments.
- Output: 585×226.
- Duration: 60 seconds.
- Samples: 1,677.
- Mean: 35.694 ms.
- Median: 35.513 ms.
- 95th percentile: 38.221 ms.
- Range: 31.719–62.626 ms.
- Verdict: pass.  Both the under-50-ms median and under-100-ms p95 budgets pass.

* Resulting implementation constraint

The production view uses three aligned image regions from one coordinate
manifest:

1. Upper player glass, redrawn for track, art, seek, and radio-state changes.
2. Lower control deck, redrawn at meter cadence while visible and playing.
3. Playlist, redrawn for queue, selection, and scroll changes.

The editable neutral source remains lossless and full resolution.  The opaque
runtime deck export is sized for the normal dock and may use a high-quality JPEG
after visual comparison with PNG; it is not the editable source.  A wider dock
may select a larger cached export, but V1 never returns to full-instrument
meter-rate rasterization.

* Related artifacts

- [[file:2026-07-19-music-config-ui-remodel-prototype-1.html][Functional browser prototype]]
- [[file:../2026-07-19-music-config-ui-remodel-render-fixture.svg][Full-render SVG fixture]]
- [[file:../2026-07-19-music-config-ui-remodel-spec.org][Music Config UI Remodel spec]]