Adaptive bitrate streaming (HLS)
Also known as: HLS, adaptive streaming, ABR streaming, DASH streaming
Adaptive bitrate streaming delivers video in short segments at multiple quality levels and switches between them on the fly to match your connection. HLS and MPEG-DASH are the common protocols — they are why streams scale resolution up or down to avoid buffering.
- Switches quality per segment to match bandwidth
- HLS and MPEG-DASH are the main protocols
- Cached segments can take device storage
How adaptive streaming works
The source video is encoded at several bitrates and resolutions, each split into short segments of a few seconds. A manifest (a playlist file) lists these versions, and the player downloads segments one at a time.
As your bandwidth changes, the player picks a higher- or lower-quality segment for the next chunk. A strong connection pulls a sharp, high-bitrate stream; a weak one drops to a smaller version to keep playing without stalling.
HLS, DASH, and storage
HLS (HTTP Live Streaming), originated by Apple and widely supported, and MPEG-DASH are the dominant adaptive protocols. Both rely on the same idea of segmented, multi-quality delivery over ordinary web servers.
Streaming itself stores nothing permanent, but downloaded or cached segments can take real space on a device. App caches from streaming services are a common reason storage fills, and clearing the cache reclaims it.