Formats & playback 6 min read
What Is m3u8: How HLS Streaming Works, Plays and Downloads
An m3u8 file is not a video — it is a plain-text playlist pointing at video segments (usually 2–10 second TS or fMP4 chunks). Apple invented HLS for adaptive streaming; it now runs most live and VOD delivery worldwide.
How the pieces fit
- Master playlist: lists multiple quality variants (1080p/720p/480p...).
- Media playlist: one variant, listing segment URLs in order plus durations.
- Segments: the actual media chunks; encryption (AES-128) keys may be referenced in the playlist.
- Player behavior: fetches the playlist, picks a variant by bandwidth, downloads segments sequentially — this is why scrubbing feels instant on streams.
Playback and legitimate capture
- Playback: Safari natively; Chrome/Edge via hls.js (this site includes an HLS player path).
- Recording your own streams (lectures you own, self-hosted cameras): capture is straightforward since segments are plain HTTP.
- DRM-protected commercial streams (Widevine/FairPlay) are not accessible — and circumvention is illegal in most jurisdictions. Respect copyright: only capture content you have rights to.