gorhill / ccaptioner

CCaptioner

A very simple extension which purpose is to assign a text track to a HTML5 video element in a web page.

Many HTML5 video players do not offer the ability to import text track for captions/subtitles purpose. The purpose of this extension is to remediate this problem.

When you want to assign a text track to a video element in a web page:

• Open the popup menu and click "Assign text track to..."
• Move the mouse over the target video element
  • Click the video element if needed
• A file picker will appear
• Pick the .srt or .vtt file to use as text track

The video should now render the captions/subtitles of the file you selected.

The content scripts of CCaptioner are injected if and only if you click on its toolbar icon while on a specific web site, and only for that web site. Once the text track is embedded, the content script terminates and should be garbage-collected by your browser's JavaScript engine.

Once a text track has been assigned to a video element on a given page, you can time-shift the text track through CCaptioner's popup panel -- this is useful when the text track is not well synchronized with the video content.

Install

Firefox 68 and above

Firefox's AMO: https://addons.mozilla.org/firefox/addon/ccaptioner/.

Chromium

Chrome Web Store: https://chrome.google.com/webstore/detail/ccaptioner/lckmkmkmghpklkkbfhhfgalajdnjcnbn.

Sideloading

You can sideload the extension by downloading the appropriate package from the Releases section.

Permissions

activeTab

This permission means that the extension will be able to interact with a web page only when you click its icon in the toolbar; so CCaptioner's content script is injected only when you demand it by clicking CCaptioner's toolbar icon.

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This permission is necessary to ensure CCaptioner's content script can also be injected in embedded iframe elements in a page -- it is not uncommon for video players to be inside an iframe which origin is different from the origin of the root document.

Credits

The CCaptioner's icon is from https://en.wikipedia.org/wiki/File:Closed_captioning_symbol.svg.