Abandoned: I don't have time to work on this and changes on Netflix's end have broken the extension. Feel free to fork it if you wish to fix it!
This is a Firefox addon for loading arbitrary subtitles in the SRT format onto any Netflix video. This lets you fill in the gaps for titles that are missing subtitles as well as allow you to use foreign languages that do not have subtitles!
https://addons.mozilla.org/en-US/developers/addon/netflix-srt-subs/edit
Usage is easy-peasy. Once installed, the addon will make a small "knob" appear at the top right corner (don't worry, this fades away after a few seconds of not moving your mouse!):
Hovering over this knob will reveal a prompt to select an SRT file to use:
There are many places you can get SRT files for videos, such as:
- subscene.com
- addic7ed.com
- opensubtitles.org
Note: This is not an endorsement of these sites. Use them with caution. Never download or run executables. An adblocker is recommended.
You can also make subtitles yourself with programs like (again, not an endorsement):
- Subrip
- Aegisub
- Subtitle Edit
The SRT format is also simple enough to write in a plain text editor.
- Subtitles sync to the video's elapsed time, even when pausing, buffering occurs, and seeking.
- Basic text formatting (bold, italics, underlined, colours, and different font sizes) are supported in SRT files.
- Offsets can be specified on the fly for subtitles that are off sync.
- Effective SRT file parsing that can handle things like non-linear subtitles, overlapping timings, and various unusual cases.
- Subtitle positioning is aware of the video size and if controls are visible, resulting in an experience comparable to Netflix's native subtitles.
Sadly, the nature of Netflix not having any form of official API for their in-browser player means we are vulnerable to things breaking simply due to changes in the page structure. That's not to lay blame on Netflix or anything, but simply to highlight that things breaking can be inevitible. Please file an issue if it happens with details (browser version, video, anything specific that you did, etc).