Tutorials Developer

Iraj Sodagar: The Standard That Made Streaming Adaptive

By Infinite Creation · Profile

At a Glance

Before adaptive streaming, video either played or stalled. DASH, standardised through MPEG and described by Sodagar in IEEE MultiMedia in 2011, cuts a stream into short segments at several qualities and lets the player choose which to fetch next. When the connection weakens the picture softens instead of stopping, which is a far better failure than a spinning wheel.

Lived: active from the 1990s, Iranian-American
Anchor year: 2011, MPEG-DASH standard described in IEEE MultiMedia
Strand: overlooked

Career

The problem as it stood

Streaming used specialised protocols and specialised servers, which did not pass through ordinary web infrastructure cleanly and could not use existing caches. A drop in bandwidth meant a stall, because the stream had one quality and no way to change it.

What he actually did

Sodagar led the MPEG work that produced Dynamic Adaptive Streaming over HTTP and wrote the paper describing it for IEEE MultiMedia in 2011. The design deliberately uses plain HTTP so that the entire existing web delivery apparatus works unchanged.

How it worked

The content is cut into segments and encoded at several bitrates. A manifest lists what exists. The player measures its own throughput and picks the next segment accordingly, so adaptation is a client decision and the server stays a plain file server.

What it made possible

Adaptive streaming over ordinary web infrastructure, cacheable by ordinary content delivery networks. DASH and Apple's HLS solved the same problem in the same way at the same time, and between them they are how internet video is delivered.

Where the credit landed

DASH is an MPEG standard with many contributors, and Sodagar's paper is the clearest single account of it by somebody who led the work. HLS is more visible because Apple shipped it in a product, which is usually how this goes.

Known For

Putting the adaptation logic in the player is what let the server stay a plain file server.
DASH and HLS solved the same problem separately and at the same time.
Segmented delivery is why ordinary content delivery networks work for video at all.

Knowledge Base

Background and Detail

Adaptive streaming is where this corpus's compression strand meets its delivery strand.

Why the player decides

Putting the adaptation logic in the client rather than the server is the design decision everything else follows from. The server becomes a plain file server, so ordinary caches and content delivery networks work unchanged, and the scaling problem that defeated earlier streaming protocols disappears.

Two solutions, arrived at separately

DASH and HLS were developed independently and reached almost the same design: segment the media, describe it in a manifest, let the player choose. When two teams solve a problem the same way without coordinating, it is usually because the constraints left little room. Here the binding constraint was existing web infrastructure, which had to be reused rather than replaced.

Where This Fits

DASH delivers video over ordinary web servers, the modern transmission link in A History of Broadcast Technology.

FAQ

Q: What is the difference between DASH and HLS?
A: Very little in principle. Both segment media, list it in a manifest and let the player choose. DASH came through MPEG as an open standard and HLS came from Apple, and both are widely deployed.

Q: Why did specialised streaming servers lose?
A: Because plain HTTP passes through every firewall, proxy and cache already deployed. Reusing existing infrastructure beat purpose-built infrastructure.

Vocabulary

MPEG-DASH Dynamic Adaptive Streaming over HTTP, standardised through MPEG. Media is split into short segments at several qualities and listed in a manifest, and the player chooses which to fetch as conditions change.

Manifest The index file describing what segments exist, at what qualities and durations. The player reads it first and everything after that is ordinary file fetching, which is why no special server is needed.

Adaptive bitrate Switching between encodings of different quality during playback in response to measured throughput. It converts a stall into a softer picture, which viewers tolerate far better.

Segment A short piece of media, typically two to ten seconds, requested as an ordinary file. Segmenting is what makes video cacheable by the same infrastructure that serves images and pages.

Sources

Every record below was fetched and read before it was cited here. Checked 26 August 2026.

Iraj Sodagar, The MPEG-DASH Standard for Multimedia Streaming Over the Internet. IEEE MultiMedia, volume 18, issue 4, pages 62 to 67, April 2011. Sole author, writing as somebody who led the standardisation rather than as an outside observer of it.