MPEGDASH

MPEG-DASH, short for Dynamic Adaptive Streaming over HTTP, is an international standard for streaming multimedia over the public Internet. It was developed by the Moving Picture Experts Group (MPEG) and is part of ISO/IEC, designated as ISO/IEC 23009. The core concept is to deliver media in HTTP-based segments while providing an adaptable stream that can switch between different quality representations in response to changing network conditions. A central element of MPEG-DASH is the Media Presentation Description (MPD), an XML document that describes available representations, segment formats, timing, and segment URLs.

Technically, content is divided into small media segments and delivered over standard HTTP. A DASH client selects an appropriate representation (bitrate, resolution, codec) and adapts the quality during playback. The standard supports various packaging options, including fragmented MP4 (fMP4) and, less commonly, MPEG-2 Transport Stream, and is codec-agnostic, supporting codecs such as H.264/AVC, H.265/HEVC, VP9, and AV1. It supports both on-demand and live content, with live MPDs updating to reveal new segments and enable timeshifted or DVR-style viewing.

DRM and encryption are commonly used with MPEG-DASH via Common Encryption (CENC), enabling interoperability with major digital rights management systems from Widevine, PlayReady, and FairPlay. Adoption is widespread across online video platforms, devices, and browsers, leveraging existing HTTP CDNs and caching infrastructure. MPEG-DASH competes with other streaming protocols like HLS but remains a standards-based, interoperable option that emphasizes broad codec support and adaptability to network conditions.