Hacktoberfest 2026：メンテナが10月に向けて印を付けた、オープンで初心者向けの issue。 Hacktoberfest の issue を見る

Image fetch and display optimization on the landing page (LCP 404 ms → poster priority, sizing, caching)

オープン
  • 何か問題がありますか？
#852 コメント 0 件 リアクション 0 件 担当者 0 名 GitHub で見る

メンテナーはふだん 1 日以内に返信

まだ誰も着手していません。

評価

難易度
4/5
見積もり時間
3〜5日
初心者へのやさしさ
35/100
issue の種類
リファクタリング
明瞭さ
おおむね明確
活発さ
活発
技術スタック
html, javascript
領域
frontend, performance

調査の方向性

Start in website/site/src/components/FilmScreen.astro where the hero video poster and attributes are set, then check Base.astro for a possible preload and the inline module in the built index.html. Caching needs a new website/site/public/_headers file and wrangler.jsonc, and the poster resizing belongs in the pnpm run media pipeline under website/hero-animation/. Done means the acceptance checklist holds: High poster priority in DevTools, a smaller poster on a 1318×741 viewport, Cache-Control on /media/*, and LCP under 300 ms.

索引モデルが issue の本文から書いたものです。

説明

Website
Context

LCP analysis of ema.tnsor.network (measured 2026-10-16): LCP is the hero <video>'s poster frame (/media/hero-poster.webp), landing at 404 ms with a 312 ms render delay after the image finishes downloading (~92 ms). Full diagnostics:

Metric / Attribute Value Finding
LCP Timing 404 ms Total render delay is 312 ms.
Image Priority Medium Failed fetchpriority=high check.
Resolution 1920×1080 Oversized for the 1318×741 display area.
Potential savings 39.1 KB Oversized resolution wastes bytes.
Cache policy max-age=0 Forces re-validation on every request.

Render delay breaks down to a ~205 ms layout task plus script execution (line 19, col 5131 — inline module in the built index.html) competing with the poster's first paint.

Current markup (FilmScreen.astro)
<video muted loop playsinline preload="auto" poster={poster} data-autoplay data-low-src={lowSrc} aria-label={title}>

No fetchpriority, no responsive source, and Cloudflare Workers static assets currently emit no cache headers (no _headers file; wrangler.jsonc assets.directory only).

Recommendations
  • Elevate resource priority — fetchpriority="high" on the video (applies to the poster fetch). Optionally add a <link rel="preload" as="image"> for the poster in Base.astro when the hero is above the fold.
  • Responsive sizing — the poster is 1920×1080 but the display area measured 1318×741. Serve a smaller default with srcset/<picture> (e.g. 960/1318/1920 widths), or accept the ~39 KB penalty on desktop. Note the poster doubles as the og:image, so generate both variants from the same source in pnpm run media.
  • Minimize main-thread work — the ~205 ms layout task + inline script at first paint delay the render even after the bytes arrive. Audit the initial inline module (spark canvas init, IntersectionObserver setup, reveal class) for anything that can yield or move behind requestIdleCallback.
  • Improve caching — static assets are content-hashed only in name (they aren't — hero-poster.webp has no hash). Add a website/site/public/_headers file (Cloudflare Pages syntax works with Workers static assets) mapping /media/* to a long max-age + immutable, or hash filenames. Careful: hero.mp4 changes with each hero re-render, so prefer _headers with a bounded max-age (e.g. 1 week) over immutable unless filenames get hashed.
<!-- Example: adding fetchpriority to a video poster -->
<video poster="/media/hero-poster.webp" fetchpriority="high">
  <!-- ... -->
</video>

Note: findings above were identified on a live page in DevTools. Adapt to the stack (Astro components in website/site/src/components/FilmScreen.astro, build pipeline in website/hero-animation/) rather than applying literal CSS overrides.

Acceptance
  • Poster fetch reports High priority in DevTools network
  • Poster transfer ≤ 1318×741-equivalent size on that viewport (or documented decision to keep 1080p for large screens)
  • _headers serving /media/* with Cache-Control: public, max-age≥604800 (verified with curl -sI https://ema.tnsor.network/media/hero-poster.webp | grep -i cache)
  • LCP re-measured with the same methodology; target < 300 ms
主要言語
TypeScript
スター
829
フォーク
234
平均マージ
22時間 43分
マージ済み PR（30日）
52

環境構築

はじめの一歩

  1. issue を最後まで読み、次にプロジェクトのコントリビューションガイドを読みます。
  2. 着手することを issue にコメントします — 二人が同じ作業をするのを防げます。
  3. リポジトリをフォークし、ブランチを切って変更します。
  4. issue 番号を参照したプルリクエストを送ります。

cameri/nostream のほかの issue

cameri/nostream の issue をすべて見る

似ている issue

TypeScript の issue をもっと見る

新しい issue をメールで受け取る

初心者向けの GitHub issue を短くまとめたダイジェスト。