SpeeVid от Caglar

<b>Watch at your own pace.</b> SpeeVid speeds up or slows down any HTML5 video on any website, from 0.25x to 16x, with a control that stays out of your way.

<b>Features</b>
<ul><li><b>On-video control</b>: a small badge floats over the video; hover it to open a slider and presets. Pick the corner, or let it auto-hide while you watch.</li><li><b>Keyboard shortcuts</b>: S speeds up, D slows down, A resets to 1x, Q jumps to a custom speed. Every key can be rebound, and they work on non-Latin keyboard layouts too.</li><li><b>Remembers every site</b>: the last speed you used is restored per site, and you can pin a speed for a site so it always wins. "Apply to all tabs" keeps every open tab in sync.</li><li><b>Auto speed by video length</b> (optional): start long videos at 2x and short clips at 1x. The threshold and both speeds are yours to set.</li><li><b>Keeps the pitch natural</b>: no chipmunk voices, even on sites that turn pitch correction off.</li><li><b>Copes with awkward players</b>: finds videos inside shadow DOM, and an optional aggressive speed lock beats sites that keep resetting the speed (some course platforms).</li><li><b>Podcasts and music too</b> (optional): also control audio players, not just video.</li><li><b>Time saved counter</b> (optional): see how much time watching faster has given back.</li><li><b>Make it yours</b>: light, dark or automatic theme with any accent color.</li><li><b>13 languages</b>: English, Türkçe, Deutsch, Español, Français, हिन्दी, Italiano, 日本語, 한국어, Português (Brasil), Русский, العربية, 简体中文.</li><li><b>Back up your settings</b>: export and import everything as a JSON file.</li></ul>

<b>Private by design</b>
SpeeVid collects no data. It has no server, no analytics and makes no network requests of its own. Settings and per-site speeds stay in your browser. Open source under the MIT license.

<b>Why does it run on every site?</b>
To find a video on whichever site you happen to be watching, SpeeVid has to run on every page. It only looks for video (and, if you turn it on, audio) elements, and never reads page content, URLs or your browsing history. You can switch it off per site, including with *.example.com wildcard rules.

<b>Source code and support</b>
https://github.com/Caglar-Coban/SpeeVid