m3u8

m3u8 is the UTF-8 encoded form of the M3U playlist used by HTTP Live Streaming (HLS). It is a text-based format that lists media segment URIs and streaming metadata, and files typically use the .m3u8 extension. Unlike the original M3U, which is ASCII, m3u8 supports Unicode characters and a richer set of tags.

An HLS playlist can be a master playlist or a media playlist. A master playlist begins with #EXTM3U and lists variant streams using #EXT-X-STREAM-INF, followed by the URL of each variant’s media playlist. These variants differ in bandwidth, resolution or codecs. A media playlist contains the actual media segment URIs and durations. Each segment line is preceded by #EXTINF:duration, and the playlist includes tags such as #EXT-X-TARGETDURATION and #EXT-X-VERSION; it ends with #EXT-X-ENDLIST when the stream is complete. Segments are typically MPEG-TS or fragmented MP4 files delivered over HTTP.

Usage-wise, m3u8 enables adaptive streaming by providing multiple renditions in a single master playlist. Players download the appropriate variant and switch between segments as network conditions change. The media playlists then reference the segment files, which are served over standard HTTP servers or CDNs.

Security and licensing aspects can be expressed via #EXT-X-KEY for encrypted streams (methods like AES-128 or SAMPLE-AES), and additional DRM workflows may apply outside the core HLS playlist syntax.

Common tooling includes FFmpeg for generation, and many streaming servers or players provide built-in support for HLS and m3u8 files.