StreamRec — Kay

Stream Recorder helps you save MediaSource (MSE) based video streams from your own websites, self-hosted players, or livestreams you have the rights to record — directly within Firefox.

Intended use
This extension is built for creators, developers, and site owners who need to archive their own streamed content (e.g. personal broadcasts, internal company streams, or content you have permission to record). It is not intended for use with third-party commercial streaming platforms, and users are responsible for complying with the terms of service of any site they use it on.

How it works
Stream Recorder listens to the MediaSource API within the browser and reassembles the video segments delivered to the player into a single local MP4 file, saved to your Downloads folder.

Features
- Captures MSE/HLS-based streams from sites you have permission to record
- Saves output in standard MP4 format (H.264 + AAC)
- Compatible with common media players (VLC, QuickTime, etc.)
- Simple one-click interface

Note on compatibility
Most sites work directly with no extra setup. For a small number of sites with non-standard stream formats, a separate open-source helper tool (StreamMerger) may be needed for final file assembly. This is optional and only relevant for edge cases — see the project page for details.

Please use responsibly
This extension is intended for personal archiving and recording of content you own or have explicit permission to capture. Please respect content creators' rights and each platform's terms of service.