Overview
Low-Latency MPEG-DASH (LL-DASH) enables 2-4 second glass-to-glass latency for live streaming using the industry-standard DASH protocol with CMAF (Common Media Application Format) segments. This is achieved through Gcore’s Chunked-Proxy technology that streams content immediately as it’s received, rather than waiting for complete file downloads.
When to use LL-DASH
Use LL-DASH if:
- You need 2-4 second latency for live events (sports, auctions, gaming)
- Your transcoder produces MPEG-DASH with CMAF segments
- You need broad device compatibility (Android, Smart TVs, web browsers)
- You want an industry-standard alternative to LL-HLS
Use Video Streaming Platform if:
How LL-DASH works on Gcore CDN
Traditional CDN delivery (high latency)
Standard CDNs use “Store and Forward” delivery:
- The CDN edge waits for the complete segment to download from the origin (2-6 seconds).
- Only then starts sending to viewers.
- Result: minimum latency of 10–15 seconds.
Gcore Chunked-Proxy delivery (low latency)
Gcore’s Chunked-Proxy module uses immediate streaming:
- The CDN then begins delivering the segment to viewers.
- Immediately starts streaming to viewers while still downloading.
- Uses HTTP Chunked Transfer Encoding (HTTP/1.1) or Framing (HTTP/2/3).
- Result: 2-4 second glass-to-glass latency.
Technical details: Read our engineering blog post: Optimizing HLS and DASH for 3-second latency - essential reading for CTOs and video engineers.
Requirements
To use LL-DASH via Gcore CDN:
| Requirement | Details |
|---|
| Format | MPEG-DASH with CMAF segments (.mpd manifests, .m4s segments) |
| Chunked-Proxy activation | Required - Contact Gcore Support |
| Paid CDN plan | Any paid subscription |
| Legal approval | Streaming activation from Gcore support |
Critical: Chunked-Proxy activation is mandatory for low-latency delivery. Without it, your stream will have 10-15 second latency instead of 2-4 seconds.
Quick setup
Step-by-step guide: Create a CDN Resource for Video Streaming
Select the “For Live MPEG-DASH CMAF Streaming” tab for complete instructions on:
- Requesting Chunked-Proxy activation from support
- Configuring cache rules for manifests and segments
- Enabling “Always online” for reliability
- Testing your low-latency stream
| File Type | Extension | Description |
|---|
| Manifests | .mpd | DASH Media Presentation Description |
| Video segments | .m4s, .m4v | CMAF video segments |
| Audio segments | .m4a, .m4s | CMAF audio segments |
| Initialization | .mp4 | Initialization segments for fMP4 streams |
How Chunked-Proxy works
Without Chunked-Proxy (standard CDN)
Origin → [CDN waits for full file] → CDN → Viewer
⏱️ 2-6 second delay
Total latency: 10-15 seconds
With Chunked-Proxy (Gcore CDN)
Origin → [CDN streams immediately] → Viewer
⚡ No waiting
Total latency: 2-4 seconds
- Byte-level streaming: Data flows from origin → CDN → viewer simultaneously
- Protocol optimization: HTTP/1.1 Chunked Transfer Encoding, HTTP/2 Framing
- RAM-based caching: LIVE STREAMING preset uses RAM instead of disk
- Origin shielding compatible: Reduces origin load while maintaining low latency
Activation process
Step 1: Request Chunked-Proxy activation
Contact Gcore Support with:
- Your CDN resource ID or domain
- Confirmation you’re using LL-DASH with CMAF segments
- Your origin transcoder details (Wowza, Nginx-RTMP, FFmpeg, etc.)
Processing time: Usually 1-2 business days
Using Gcore Video Streaming? If you’re using our Video Streaming Platform with transcoding, Chunked-Proxy is already enabled by default. No activation needed.
- Manifests (
.mpd): 2 second cache
- Segments (
.m4s): 60 second cache
- Always online: Enabled (error + timeout, not updating)
- LIVE STREAMING preset: Enabled for RAM caching
Best practices
Origin configuration
- Segment duration: 2-6 seconds (shorter = lower latency, higher overhead)
- Chunked encoding: Enable chunked transfer encoding on your origin
- Availability window: Keep 30-60 seconds of segments available
CDN optimization
- Origin shielding: Recommended for 100+ concurrent viewers
- Edge locations: Content cached at 210+ global edge servers
- Monitoring: Use CDN Statistics to track performance
Player compatibility
Ensure your video player supports:
- MPEG-DASH playback
- CMAF segment format
- Low-latency mode (if available)
Recommended players:
- dash.js (with low-latency mode)
- Shaka Player
- ExoPlayer (Android)
- AVPlayer (iOS/tvOS with DASH support)
Latency comparison
| Delivery Method | Typical Latency | Use Case |
|---|
| LL-DASH (Gcore Chunked-Proxy) | 2-4 seconds | Live sports, auctions, interactive events |
| Standard DASH (no Chunked-Proxy) | 10-15 seconds | News, conferences, less interactive content |
| HTTP-FLV | 1-3 seconds | Ultra-low latency for specific use cases |
| Traditional RTMP | 3-5 seconds | Legacy systems |
Technical deep dive
For video engineers and CTOs interested in the technical implementation:
Engineering blog post: Optimizing HLS and DASH for 3-second latency
This article covers:
- HTTP Chunked Transfer Encoding implementation
- HTTP/2 and HTTP/3 framing optimizations
- Origin-to-edge-to-viewer data flow
- Benchmarks and performance analysis
- Comparison with other low-latency approaches
Troubleshooting
High latency (>10 seconds)
Cause: Chunked-Proxy not activated or not working correctly
Solution:
- Verify Chunked-Proxy is activated by support
- Check origin supports chunked encoding
- Verify CMAF segments are used (not MPEG-TS)
- Contact Gcore Support for diagnostics
Buffering or playback issues
Cause: Cache settings too aggressive or manifest updates too slow
Solution:
- Reduce manifest cache to 1-2 seconds
- Ensure segment cache is 60 seconds
- Enable “Always online” (error + timeout only)
- Check origin availability and response times
Need help?
Contact Gcore Support or use the chat in the bottom-right corner.
Next steps
