DASH (Dynamic Adaptive Streaming over HTTP) is an adaptive bitrate streaming standard developed by the Moving Picture Experts Group (MPEG). It enables high-quality streaming of video and audio over the internet by dynamically adjusting the bitrate based on network conditions. DASH is widely used in OTT (Over-the-Top) streaming platforms, live broadcasting, and video-on-demand (VOD) services. Unlike HLS, which was developed by Apple, DASH is codec-agnostic and works across multiple platforms and devices.
DASH streaming divides media content into small segments, each available in multiple quality levels. A manifest file (MPD - Media Presentation Description) guides the video player to select the optimal segment based on network conditions and device capabilities.
Encoding & Segmentation
The original video is encoded into different bitrates and resolutions. Each version is broken into small segments (e.g., 2-10 seconds).
MPD (Media Presentation Description)
An MPD file (manifest file) contains metadata about available video qualities, segment locations, and playback rules. The player dynamically switches between different bitrates depending on bandwidth conditions.
Adaptive Bitrate Streaming (ABR)
If the network is stable and fast, the player streams a higher-resolution version. If bandwidth drops, it seamlessly switches to a lower bitrate to prevent buffering.
Codec Agnostic – Works with H.264, H.265 (HEVC), VP9, AV1, and other codecs.
Cross-Platform Compatibility – Unlike HLS (which is Apple-centric), DASH works on Windows, Android, Smart TVs, and major browsers.
Efficient Streaming – Provides on-the-fly quality switching to optimize video playback.
Low-Latency DASH (LL-DASH) – Introduces optimizations to reduce live-streaming latency.
Support for DRM & Encryption – Works with Widevine, PlayReady, and FairPlay DRM for content protection.
| Feature | DASH | HLS |
|---|---|---|
| Developer | MPEG | Apple |
| Platform Compatibility | Universal (Web, Android, Windows, Smart TVs) | Best on iOS/macOS (but also works on browsers) |
| Codec Support | H.264, H.265, VP9, AVI | H.264, H.265 |
| Latency | 3-10 seconds (LL-DASH: <3s) | 5-30 seconds (LL-HLS: ~3s) |
| DRM Support | Widevine, PlayReady, FairPlay | FairPlay (Apple), Widevine (limited) |
| Use Case | Broadcasters, OTT platforms | Apple ecosystem, live streaming |
Higher Complexity – MPD manifests and multi-bitrate encoding require additional setup.
Less Native iOS Support – Apple prioritizes HLS, so DASH playback on iOS requires third-party players.
Caching & Latency Issues – HTTP chunked delivery can introduce minor inefficiencies compared to WebRTC or RTMP for ultra-low-latency use cases.
DASH is a powerful, flexible streaming protocol that supports adaptive bitrate delivery across a broad range of platforms. While it competes with HLS, its open standard, codec flexibility, and compatibility with DRM systems make it a preferred choice for many broadcasters and OTT service providers. With LL-DASH improvements, it continues to evolve for low-latency streaming and next-gen media applications.