> ## Documentation Index
> Fetch the complete documentation index at: https://gcore-waap-api-guides.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# DASH and LL-DASH via CDN
> Deliver MPEG-DASH and Low-Latency DASH live streams and video-on-demand content through Gcore CDN
## Overview
MPEG-DASH (Dynamic Adaptive Streaming over HTTP) is an HTTP-based adaptive streaming protocol for live and VOD delivery. A DASH stream uses an `.mpd` manifest and media segments, so it can be cached and delivered through Gcore CDN like other HTTP video formats.
Low-Latency MPEG-DASH (LL-DASH) is the low-latency mode for DASH live streaming. It enables **2-4 second glass-to-glass latency** with CMAF (Common Media Application Format) segments and Gcore's **Chunked-Proxy** technology, which streams content immediately as it's received instead of waiting for complete file downloads.
## When to use DASH via CDN
Use Video CDN for DASH if:
* You already have DASH streams (`.mpd` manifests and media segments)
* You handle transcoding and packaging on your side
* You need broad device compatibility for Android, Smart TVs, web browsers, or custom players
* You want CDN features like geo-blocking, secure tokens, origin shielding, or custom domains
Use LL-DASH if you also need 2-4 second latency for live events such as sports, auctions, gaming, or interactive broadcasts.
## 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:**
* You need transcoding from RTMP/SRT → Use [Video Streaming](/streaming) instead
* You want automatic ABR ladder generation → Use [Video Streaming](/streaming) instead
## How LL-DASH works on Gcore CDN
### Traditional CDN delivery (high latency)
Standard CDNs use **"Store and Forward"** delivery:
1. The CDN edge waits for the complete segment to download from the origin (2-6 seconds).
2. Only then starts sending to viewers.
3. Result: minimum latency of 10–15 seconds.
### Gcore Chunked-Proxy delivery (low latency)
Gcore's **Chunked-Proxy module** uses **immediate streaming**:
1. The CDN then begins delivering the segment to viewers.
2. Immediately starts streaming to viewers while still downloading.
3. Uses HTTP Chunked Transfer Encoding (HTTP/1.1) or Framing (HTTP/2/3).
4. Result: 2-4 second glass-to-glass latency.
**Technical details:** Read our engineering blog post: [Optimizing HLS and DASH for 3-second latency](https://gcore.com/blog/optimizing-hls-dash-3sec) - essential reading for CTOs and video engineers.
***
## Requirements
To use DASH via Gcore CDN:
| Requirement | Details |
| ---------------------------- | ---------------------------------------------------------------------------- |
| **Standard DASH format** | MPEG-DASH (`.mpd` manifests and media segments such as `.m4s`) |
| **LL-DASH format** | MPEG-DASH with CMAF segments (`.mpd` manifests, `.m4s` segments) |
| **Chunked-Proxy activation** | Required only for LL-DASH. Contact [Gcore Support](mailto:support@gcore.com) |
| **Paid CDN plan** | Any paid subscription |
| **Legal approval** | Video delivery enablement from Gcore Support |
**Critical:** Chunked-Proxy activation is **mandatory** for LL-DASH low-latency delivery. Without it, DASH delivery works as standard CDN delivery with higher latency, typically 10-15 seconds instead of 2-4 seconds.
***
## Quick setup
**Step-by-step guide:** [Create a CDN Resource for Video Streaming](/cdn/getting-started/create-a-cdn-resource/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
***
## Supported file formats
| 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
```
**Key technical advantages:**
* **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](mailto:support@gcore.com) 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](/streaming) with transcoding, Chunked-Proxy is **already enabled by default**. No activation needed.
### Step 2: Configure CDN resource
After activation, follow the cache configuration steps in the [Getting Started Guide](/cdn/getting-started/create-a-cdn-resource/create-a-cdn-resource-for-video-streaming#step-4-configure-caching-rules).
**Key settings:**
* **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](/cdn/view-statistics-of-a-cdn-resource) 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](https://gcore.com/blog/optimizing-hls-dash-3sec)
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:**
1. Verify Chunked-Proxy is activated by support
2. Check origin supports chunked encoding
3. Verify CMAF segments are used (not MPEG-TS)
4. Contact [Gcore Support](mailto:support@gcore.com) for diagnostics
### Buffering or playback issues
**Cause:** Cache settings too aggressive or manifest updates too slow
**Solution:**
1. Reduce manifest cache to 1-2 seconds
2. Ensure segment cache is 60 seconds
3. Enable "Always online" (error + timeout only)
4. Check origin availability and response times
### Need help?
Contact [Gcore Support](mailto:support@gcore.com) or use the chat in the bottom-right corner.
***
## Next steps
Complete setup instructions to create a CDN resource for video streaming
Alternative HLS formats for standard and low-latency streaming
All Video CDN features and capabilities
Technical deep dive: 3-second latency optimization