Adaptive bitrate streaming
Adaptive bitrate streaming is a technique used in streaming multimedia over computer networks. While in the past most video or audio streaming technologies utilized packetized, stateful, single-bitrate streaming protocols such as RTP with RTSP, today's adaptive streaming technologies are based almost exclusively on HTTP, and are designed to work efficiently over large distributed HTTP networks.
Source: Wikipedia — Adaptive bitrate streaming (CC BY-SA 4.0)