Bitratestreaming

Bitratestreaming is a method of delivering audio and video content over the internet by using multiple encoded representations at different bitrates and allowing the client to switch between representations during playback to cope with changing network conditions. It is commonly referred to as adaptive bitrate streaming.

The technique works by encoding the same media at several quality levels, creating a ladder of bitrates and resolutions. The content is divided into short segments, typically a few seconds long, and each segment is available in all representations. A manifest or playlist (such as those used by HLS or DASH) lists the available representations. The client continuously measures network bandwidth and playback buffer occupancy, then requests the next segment from the representation that best matches current conditions. If bandwidth increases, the client may switch to a higher bitrate; if it drops, it may switch down to a lower bitrate. This switching is designed to be seamless and minimize playback interruptions.

Standards and formats commonly supporting bitratestreaming include HTTP-based protocols such as Apple's HLS (HTTP Live Streaming) and the MPEG-DASH standard (Dynamic Adaptive Streaming over HTTP). These typically rely on segment-based delivery and may use common containers like CMAF to improve compatibility and efficiency. Bitrate streaming can employ constant or variable audio/video encoding within each representation, with ABR algorithms balancing startup time, average quality, and rebuffering risk.

Applications include on-demand and live video delivery, where the primary goals are to maximize viewer quality under varying network conditions while controlling latency and buffering.