Video Streaming Protocols: HLS, DASH and More

Video streaming relies on protocols to split media into small pieces and describe where to fetch them. Two of the most widely used are HLS and DASH. Both run over standard HTTP, making delivery easy with CDNs and common servers. They also support multiple quality levels so the player can adapt to changing networks.

How HLS works

HLS uses a simple manifest called an M3U8 file. It lets the player choose among different video bitrates and resolutions and then fetches short video segments. Because HTTP is cache-friendly, CDNs can help scale delivery for large audiences. HLS has broad device support, especially on Apple devices, but is also widely used on Android, browsers, and smart TVs.

How DASH works

DASH uses a manifest called an MPD and media segments that can be packaged as CMAF. It is an ISO standard and tends to offer robust interoperability across players and encoders. With DASH, you can separate codecs, resolutions, and timing more explicitly, which helps when you manage complex streams or need precise analytics.

Older formats like Smooth Streaming and Adobe HDS still exist in some places, but their use is shrinking. Modern workflows often deliver both HLS and DASH to cover a wide range of devices. Low-latency variants are growing in popularity: LHLS for HLS and LL-DASH for DASH aim for faster live delivery, though they demand coordinated packaging and compatible clients.

Choosing a protocol for your project

Consider your audience, devices, and latency needs. If you ship to many Apple devices or rely on iOS features, HLS is a solid baseline. If you require strict standardization and deeper codec flexibility, DASH can be beneficial. Packaging with CMAF often helps reduce file counts and improve caching across platforms.

Practical tips

  • Test on real devices and networks, not just simulators.
  • Offer both HLS and DASH in your live or on‑demand catalog.
  • Use CMAF for cross‑compatibility and better caching.
  • Plan for latency needs: if sub‑second delay matters, explore LL variants and CDN tuning.
  • Verify DRM options and encryption to protect content.

Key Takeaways

  • HLS and DASH are the core HTTP streaming protocols, each with strengths.
  • CMAF packaging aids compatibility and efficiency.
  • Low-latency options exist, but require careful implementation and testing.