MPEG-DASH is the ISO/IEC 23009-1 standard for adaptive streaming over HTTP. A video is encoded at several qualities, cut into short segments, and described by an XML manifest called the MPD. The player fetches segments over plain HTTP and switches renditions as bandwidth changes. It is codec- and DRM-agnostic and is the vendor-neutral counterpart to Apple's HLS.

What is the difference between MPEG-DASH and HLS?

Both deliver adaptive video as HTTP segments with a manifest. HLS uses M3U8 playlists and is Apple's format, with native support on iPhone and iPad; DASH uses an XML MPD and is the ISO standard with broad support elsewhere and more flexibility in codecs and DRM. Since both can use CMAF segments, most services package one set of files and serve HLS to Apple devices and DASH or HLS to the rest.

Does MPEG-DASH work on iPhone?

Not natively. Safari on iOS has historically lacked the Media Source Extensions that DASH players need, and Apple's native player only understands HLS. Native iOS apps can bundle a third-party DASH player, but most services simply serve HLS to iOS from the same CMAF segments. On desktop Safari, Chrome, Firefox, Edge, Android and smart TVs, DASH plays through dash.js, Shaka Player or a platform player.

The MPD, or Media Presentation Description, is the XML manifest of a DASH stream. It lists Periods of content, Adaptation Sets for video, audio languages and subtitles, and Representations for each quality level, along with how to build segment URLs and any encryption details. For live streams the player re-fetches the MPD periodically to learn about new segments.

Is MPEG-DASH used for video calls?

No. DASH delivers pre-segmented media with several seconds of latency, which is fine for broadcasts and on-demand playback but far too slow for a conversation. Interactive calls use WebRTC, where media flows as RTP packets and a media server such as an SFU forwards simulcast layers in real time. Ethora, for example, runs calls on WebRTC and would hand off to a DASH or HLS pipeline only for broadcasting recordings.

Glossary

MPEG-DASH

The vendor-neutral standard for streaming over HTTP. MPEG-DASH describes a video as an XML manifest plus segments at several qualities, so any compliant player on any platform can stream it adaptively from an ordinary web server or CDN.

General definition

MPEG-DASH stands for Dynamic Adaptive Streaming over HTTP. Published by ISO/IEC as 23009-1 in 2012 and revised since, it standardises the manifest and segment structure for adaptive bitrate streaming without tying itself to any codec, container or DRM system. Where HLS began as an Apple technology, DASH was written by the MPEG committee with contributions from across the industry and is the format that vendor-neutral players and many large streaming services build on.

The manifest is the Media Presentation Description (MPD), an XML document. It is organised into Periods (for example the main content and ad breaks), each containing Adaptation Sets (one for video, one per audio language, one per subtitle track), each containing Representations: the individual renditions at a given resolution, bitrate and video codec. Segments are usually fragmented MP4, addressed by templates or explicit lists, and for live streams the MPD is refreshed as new segments appear. Players such as the DASH Industry Forum’s dash.js and Shaka Player implement the switching logic on top of the browser’s Media Source Extensions.

CMAF (ISO/IEC 23000-19) defines a common fragmented MP4 segment format so one set of files can be served through both a DASH MPD and an HLS playlist
Common Encryption (CENC) lets a single encrypted segment set work with several DRM systems, which is a large part of why DASH is favoured for premium content
Low-latency DASH uses chunked CMAF segments delivered with HTTP chunked transfer, bringing live delay down to around 2 to 4 seconds from the 10 to 30 seconds of classic DASH
Ingest is a separate concern: a live source typically reaches the packager over RTMP, SRT or WebRTC and is transcoded into the DASH ladder there

The practical limitation is Apple. Safari on iPhone has historically lacked the Media Source Extensions support that DASH players rely on, so services that must reach iOS serve HLS there and DASH elsewhere, usually from the same CMAF segments. DASH is a delivery format for one-to-many playback with seconds of latency; it is not a real-time protocol and is not used for interactive calls.

In the Ethora ecosystem

Ethora does not stream DASH or HLS. Its media path is real-time: voice and video calls on WebRTC through an SFU media server, where the SFU forwards simulcast layers to each participant within milliseconds, and audio-only calls are available as an opt-in. That design fits conversations between users of your app, which is what a chat platform hosts, and it is a different problem from broadcasting a finished stream to a large audience.

Products that need both, for example a telehealth service that also publishes recorded education sessions, or a community app with live events, keep the interactive part on the calling stack and use a separate packaging pipeline to produce DASH or HLS output. On a dedicated or self-hosted Ethora deployment such a pipeline can sit in the same cloud account as the chat backend, keeping recordings under the same data residency and access controls as the messages. The voice and video call API page lists the calling features in the SDK.

MPEG-DASH

General definition

In the Ethora ecosystem

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