What is M3U8?
A practical guide to the M3U8 playlist format and the HLS streaming protocol.
Introduction
M3U8 is a UTF-8 playlist format used by HLS (HTTP Live Streaming). It does not usually contain the video itself; it points to media segments, variants, keys, and metadata.
HLS was introduced by Apple and is now widely used for live streaming and on-demand video across browsers, apps, and OTT platforms.
How M3U8 works
1. Server segmentation
The server splits a video into short TS or fMP4 segments and writes an M3U8 index file.
2. M3U8 index
The playlist records segment URLs, playback order, duration, variants, and related metadata.
3. Progressive download
The player downloads segments in order and starts playback before the full video is available.
4. Adaptive bitrate
A master playlist can provide multiple qualities, so the player switches according to network conditions.
M3U8 file structure
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:0
#EXTINF:9.009,
http://media.example.com/first.ts
#EXTINF:9.009,
http://media.example.com/second.ts
#EXTINF:3.003,
http://media.example.com/third.ts
#EXT-X-ENDLIST#EXTM3U - file header for an M3U playlist
#EXT-X-VERSION - HLS protocol version
#EXT-X-TARGETDURATION - maximum segment duration
#EXTINF - segment duration and URL
#EXT-X-ENDLIST - marks VOD playlist end
M3U8 vs MP4
M3U8 advantages
- Supports live streaming.
- Adapts quality to bandwidth.
- Starts quickly without downloading the full file.
- Works well with CDN caching.
- Supports encryption.
M3U8 limitations
- Not ideal for local file playback without an HTTP server.
- Many files can be harder to manage.
- Latency can be higher than direct file playback.
- Older devices may need a compatible player.
- Saving offline is less simple than MP4.
Common use cases
Live video
Sports, news, events, and game streams.
VOD platforms
Video sites, online education, and OTT libraries.
Mobile apps
Video playback in phone and tablet applications.
How to use M3U8
Online playback
Open a direct M3U8 URL in an HLS-capable player such as M3U8 Player.
Download and save
Use an M3U8 downloader to fetch segments and merge them when you have permission.
Format conversion
Use FFmpeg or a converter to create MP4 from an allowed M3U8 source.