Adaptive bitrate streaming (ABS) is a performance management technique for streaming multimedia over computer networks. Historically, most video streaming approaches were founded on RTP or RTSP; but now most adaptive streaming technologies are built for tranmission over HTTP over large, broad-distribution networks.
ABS works by dynamically monitoring CPU and memory capacity and then making corresponding adjustments to video quality. The heart of the process involves encoding the source video at varying bit rates, and then segmenting each of the different bit rate streams into small parts. The segment length typically varies between 2 and 10 seconds. The user’s multimedia player can take advantage of ABS if it has the capability to switch among the different bitrate segments—locating the segments that correspond best to the bandwidth on the user’s computer.
The catalog of segments and bitrates is written into a manifest file. When the user accesses the multimedia file, the user’s computer requests the segments from the lowest bit rate stream (given in the manifest file). If the user’s video player detects that the download speed exceeds the bit rate of the initial segment, it will request the next higher bit rate segment (again, written in the manifest file). This process will continue until a close match is found between the current bitrate segment and the user’s available bandwidth. The video will then play at that bitrate. Later, if user bandwidth changes, it will request a different bit rate segment. The result—very often—is minimal buffering, quick video initialization, and a good experience on both high-bandwidth and low-bandwidth connections.
At Encoding.com, the beauty of ABS is its simplicity and flexibility: after changing a few settings during the encoding process, you can send live or pre-recorded audio and video to various devices using an ordinary web server. Since it is designed to accommodate the wide range of mobile devices and network capacities, ABS can dynamically adjust movie playback quality to match the available speed of wired or wireless networks. ABS enables streaming media consumers to experience the highest-possible quality playback because it automatically detects the user’s network and playback conditions in real time in conditions that are subject to change.
Three types of Adaptive Bitrate Streaming
Encoding.com offers you the flexibility of using any of the three major implementations of ABS: Apple’s HTTP Live Streaming, Adobe’s HTTP Dynamic Streaming, and Microsoft’s Smooth Streaming. Use the + buttons below to read more about each implementation.
NOTE: It’s important to understand your target audience and then choose the ABS variant that’s best for your application.