Firefox Note
FastStream replaces website video players with a custom browser player focused on buffering and accessibility features.
About Firefox Note
FastStream is a browser extension that replaces video players on websites with its own player. Its stated focus is buffering and accessibility. The extension pre-buffers video in the background using automatic fragmentation and parallel requests, which the project says can produce download speeds up to 6x faster. The player supports MP4, HLS (.m3u8), and DASH (.mpd) streams, and YouTube playback is supported with download limitations on Chrome unless the extension is installed manually.
The project states that the extension does not collect telemetry and works offline without requiring additional internet resources. Limits include no support for livestreams, no support for DRM-protected content, and a default pre-buffer maximum of 5GB, which can be changed in settings. The project describes the player as a work in progress and notes that some users have reported YouTube problems.
Key features
- Background pre-buffering with automatic fragmentation and parallel requests
- Subtitle appearance settings, built-in OpenSubtitles search, and a subtitle syncing tool
- Audio controls including equalizer, compressor, mixer, mono mode, and volume booster
- Video adjustments for brightness, contrast, hue, and LMS daltonization for color blindness
- More than 20 remappable keybinds and accessible tool buttons
- Sources Browser for playing streams detected in other tabs, plus local file drag and drop
Best for: People who watch videos on websites with slow connections or who need subtitle, color vision, or keyboard control options.
Good for
- The project states that the extension does not collect telemetry.
- It is described as working fully offline without additional internet resources.
- It includes accessibility options such as color blindness adjustment and remappable keybinds.
Watch out for
- Livestreams are not supported, and the project says they will not be supported in the near future.
- The player does not work with DRM-protected content.
- The project describes the player as a work in progress, and some users have reported YouTube issues.
Firefox Note at a glance
- Category
- Software & Utilities › Media Players & Servers
- Type
- Open-source project
- Pricing
- Not confirmed. Check the site
- Open source
- Not stated
- Language
- English
- Last checked
- Oct 6, 2026 · Online when checked
- Listed
- Oct 5, 2026
Guides for Media Players & Servers
Firefox Note alternatives
Tools and sites you could use instead, ranked by how closely they match.
Replace website video players with FastStream, a browser extension offering a custom player focused on buffering and accessibility features.
ff2mpv adds a browser action for opening the current page URL or a selected link in the mpv media player.
Metastream synchronizes streaming media across Chromium and Firefox, with sessions, chat, a shared queue, and host-managed playback permissions.
Watch videos in sync with friends using SyncWatch, a browser extension that lists support for Firefox, Chrome, and Opera.
Open source
24 alternatives
uView keeps supported online videos and local media visible in a small always-on-top window while you use other apps.
Use MotionMonkey, a touch-focused semantic player, to find and stream internet videos from text queries.
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Firefox Note FAQ
Which video formats does the player support?
The player supports MP4 (.mp4), HLS streams (.m3u8), and DASH streams (.mpd). YouTube is also supported, but downloads are not supported on Chrome unless the extension is installed manually.
How much storage does pre-buffering use by default?
The default maximum for pre-buffering is 5GB, which can be changed on the settings page. The project advises caution with storage space, and notes that frequent pre-buffering of large videos can reduce SSD lifespan.
Does the extension collect usage data?
The project states that the extension does not collect telemetry and does not require additional internet resources to function.
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