# [Install from Chrome Web Store][chrome-web-store-link]

[![Chrome Web Store][chrome-web-store-version]][chrome-web-store-link] [![Chrome Web Store Users][chrome-web-store-users-badge]][chrome-web-store-link] [![Chrome Web Store Users][chrome-web-store-stars]][chrome-web-store-link]  

**Video Speed Controller** gives you fine-grained control over any HTML5 video
or audio element, on any site.

## The science of accelerated playback

**TL;DR** -- faster playback translates to better engagement and retention.

The average adult reads at [250-300 words per minute][wpm-study] (wpm). Speech
averages ~150 wpm; slide presentations often closer to 100 wpm. Given the
choice, most viewers [speed up playback to ~1.3-1.5x][ms-study] to close the
gap. Accelerated viewing [keeps attention longer][byu-study] -- faster delivery
means higher engagement. With practice, many settle at 2x or above and find it
[uncomfortable to return to 1x][mit-study].

[wpm-study]: http://www.paperbecause.com/PIOP/files/f7/f7bb6bc5-2c4a-466f-9ae7-b483a2c0dca4.pdf
[ms-study]: http://research.microsoft.com/en-us/um/redmond/groups/coet/compression/chi99/paper.pdf
[byu-study]: http://www.enounce.com/docs/BYUPaper020319.pdf
[mit-study]: http://alumni.media.mit.edu/~barons/html/avios92.html#beasleyalteredspeech

HTML5 media elements expose a native playback rate API, but most players hide
or artificially limit it. Speed adjustments should be effortless and frequent:
we don't read at a fixed pace, and we shouldn't watch at one either.


## Features

- **Universal** - works on any site with HTML5 media: YouTube, Netflix,
  Coursera, podcasts, local files, etc.
- **Video and audio** - controls both `<video>` and `<audio>` elements.
- **Fine-grained speed** - 0.07x to 16x in configurable increments.
- **Per-site speed rules** - set a default playback speed for specific domains
  (e.g., always 2x on lecture sites).
- **Per-site disable** - turn off the controller on sites where you don't
  want it.
- **Remember speed** - optionally persist your last speed across sessions
  and tabs.
- **Speed fightback** - automatically re-applies your chosen speed when a
  site's player tries to reset it.
- **Draggable overlay** - reposition the on-video speed indicator anywhere
  you like.
- **Fully customizable shortcuts** - remap every key, add modifier combos
  (Ctrl, Shift, Alt), create multiple preferred-speed toggles.
- **Custom controller CSS** - style or reposition the overlay with your own
  CSS rules.

## Default keyboard shortcuts

- **S** - decrease playback speed
- **D** - increase playback speed
- **R** - reset playback speed to 1.0x
- **Z** - rewind video by 10 seconds
- **X** - advance video by 10 seconds
- **G** - toggle between current and preferred speed
- **V** - show/hide the controller
- **M** - set a marker at current position
- **J** - jump back to the previously set marker

All shortcuts are fully customizable in the extension's settings page. You can
reassign keys, add modifier combinations, and define multiple preferred-speed
shortcuts with different values for quick toggling. Click **Add New** in
settings to create additional bindings. Refresh the page after making changes
for them to take effect.

## License

(MIT License) - Copyright (c) 2014 Ilya Grigorik

[chrome-web-store-version]: https://img.shields.io/chrome-web-store/v/nffaoalbilbmmfgbnbgppjihopabppdk?label=Chrome%20Web%20Store
[chrome-web-store-users-badge]: https://img.shields.io/chrome-web-store/users/nffaoalbilbmmfgbnbgppjihopabppdk
[chrome-web-store-stars]: https://img.shields.io/chrome-web-store/stars/nffaoalbilbmmfgbnbgppjihopabppdk
[github-release-badge]: https://img.shields.io/github/v/release/igrigorik/videospeed

[chrome-web-store-link]: https://chromewebstore.google.com/detail/video-speed-controller/nffaoalbilbmmfgbnbgppjihopabppdk
[github-release-link]: https://github.com/igrigorik/videospeed/releases