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Research Notebook

HTTP Adaptive Streaming

Introduction

Adaptive bitrate streaming from Wikipedia.

Adaptive bitrate streaming is a technique used in streaming multimedia over computer networks. While in the past most video streaming technologies utilized streaming protocols such as RTP with RTSP, today's adaptive streaming technologies are almost exclusively based on HTTP and designed to work efficiently over large distributed HTTP networks such as the Internet.

It works by detecting a user's bandwidth and CPU capacity in real time and adjusting the quality of a video stream accordingly. It requires the use of an encoder which can encode a single source video at multiple bit rates. The player client switches between streaming the different encodings depending on available resources.

Adaptive streaming overview bit rates

Figure 1. This image is licensed under the CC Attribution-Share Alike 3.0 Unported license.

Implementations

MPEG-DASH

MPEG-DASH is the only adaptive bit-rate HTTP-based streaming solution that is an international standard. The scope of the MPEG-DASH standard was limited to the Media Presentation Description (MPD) format of the manifest files as well as the segmentation standards for the server.

With the increase of Internet bandwidth and the tremendous growth of the World Wide Web, the value of delivering audio or video data in small packets has diminished. Multimedia content can now be delivered efficiently in larger segments using HTTP.

DASH-AVC/264

In order to help speed adoption of MPEG-DASH, the DASH Industry Forum proposed a reduced specification, which was limited to a single Codec (AVC/h.264) and narrowed the options available within the MPD. This specification is known as DASH-264.5 As part of the DASH Industry Forum, Digital Primates was charged with building the DASH-264 reference client.

Papers and Presentations in Conferences

Resources

Resources in Spanish

Glossary

People