Old Reddit Offline Video Download 作者： Jared Dishman

A Firefox extension that adds a Download button to Reddit-hosted video posts, saving them as MP4 files with audio. All entirely in the browser, no external services required.

Features

• Only works on old Reddit (old.reddit.com)
• No data leaves your browser. All processing is done locally
• Merges the separate video and audio streams Reddit serves via DASH into a single MP4
• Shows a progress bar during fetch and mux stages

How It Works

Reddit hosts videos as DASH streams: a video-only track and an audio-only track served separately from v.redd.it. This extension:

1. Detects video posts via DOM attributes, <shreddit-player> elements, and the DASH manifest
2. Injects a Download button into each post's action bar
3. On click, the background script fetches the video and audio streams with progress reporting
4. The streams are remuxed into a standard non-fragmented MP4 using a custom mp4box-based pipeline
5. The finished file is downloaded directly to your browser's downloads folder