Adaptive Bitrate (ABR) is the shorthand term for the family of streaming techniques that dynamically adjust the quality of a live video stream in response to changing network conditions. An ABR streaming system encodes content at multiple bitrate levels and continuously monitors the viewer's download speed and buffer health. When conditions degrade, it seamlessly switches to a lower quality tier to maintain uninterrupted playback. When conditions improve, it steps back up to higher quality, all without any action from the viewer.