How Hulu Evolved Its Video Platform Across Three Generations

Technology Selection Journey

This article is based on a 2015 talk by Hulu Senior Software Development Manager Li Bin at the TOP100 Global Software Case Study Summit about the evolution of Hulu’s cross‑platform video system.

First Stage: Flash‑Based Video System

In its earliest days, Hulu used Adobe Flash plug‑ins to deliver video directly in browsers, giving it a competitive edge over rivals that required desktop clients. Flash provided cross‑platform playback on most desktops, though it lacked coverage on iOS, Android, and living‑room devices, necessitating additional formats and workflows for those platforms.

Adobe supplied an end‑to‑end solution: Adobe Media Server, VP6/MP3 with RTMP, and the Flash plug‑in on the client side. The main limitation was poor mobile and TV device support.

Second Stage: HLS + H264 Multi‑Platform, Multi‑Format System

With the launch of Hulu Plus, mobile and TV devices became a priority, prompting a shift to Apple’s HLS format and H264/AAC codecs, which are widely supported across devices. DRM requirements also grew, leading to multiple encryption schemes for different DRM providers.

These trends simplified the workflow—H264 allowed a single encode per video for all profiles—but introduced storage and CDN costs due to the need for many format and DRM variants.

Third Stage: MPEG‑DASH Video System

In 2013, MPEG‑DASH emerged, combining advantages of HLS, HDS, and Smooth Streaming while adhering to industry standards. DASH uses segmented MP4 (moof+mdat) files, reducing the number of files and CDN costs compared to HLS.

Hulu leveraged the fact that Microsoft’s Smooth Streaming and DASH share the same PIFF‑based encryption, allowing reuse of assets across both formats.

DASH employs an XML MPD (Media Presentation Description) file to describe media, supporting multiple tracks and DRM information in a single file.

Video System Architecture

The core idea of the DASH‑based system is to simplify backend logic and push intelligence to the client, resulting in a clear, maintainable, and scalable backend. An independent QoS monitoring system tracks key metrics (viewer count, buffer ratios, content/ad load speeds) and adjusts backend rules in real time.