Low-latency DASH
Low-latency DASH (LL-DASH) is a mode of MPEG-DASH that reduces live streaming delay to a few seconds by sending video in small chunks while each segment is still being encoded. It relies on CMAF chunks and HTTP chunked transfer encoding, so the player receives frames almost as soon as they are produced. The player also keeps a small buffer and adjusts playback speed slightly to stay close to live.
Why it matters
For live events with chat, betting or voting, a delay of 20 seconds or more breaks the experience and lets social media spoil key moments. Low-latency DASH cuts that delay to a few seconds while still using standard CDNs, so a business can scale to large audiences without moving to costly real-time servers.
How it works
- The encoder produces each segment as a series of small CMAF chunks, each holding a fraction of a second.
- The CDN forwards each chunk to the player as soon as it arrives, using HTTP chunked transfer encoding.
- The player starts decoding chunks before the full segment exists, keeping only a small buffer.
- The player speeds up or slows down playback slightly to stay close to its target delay.
LL-DASH vs LL-HLS: what is the difference?
Both cut live delay to a few seconds, but they work differently. Low-latency DASH sends CMAF chunks over chunked transfer encoding, so data flows to the player as it is encoded. LL-HLS lists small partial segments in its playlist and lets the server hold playlist requests until new parts exist. Many services use the same CMAF media for both and choose by device.
Why does low-latency DASH buffer more?
Low-latency DASH buffers more because the player keeps a very small safety buffer to stay close to live. With only a second or two of video stored, any short network dip can empty it and cause a stall. Teams usually tune the target delay per audience, accepting a little more delay for viewers on weak or mobile connections.
Where it's used
Live sports streamers and live event platforms with chat, voting or betting use low-latency DASH to keep online viewers close to the broadcast on Android, Chrome and smart TVs.
