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Rule examples: DASH

MPEG-DASH delivers adaptive streaming through an XML manifest (.mpd) that references fragmented MP4 segments (.m4s). As with HLS, the manifest must stay fresh while segments can be cached a little longer. This page provides a template of cache rules and a CORS header rule tuned for DASH players such as dash.js.

Manifest vs. segment TTLs​

A live .mpd is updated as the presentation advances, so it needs a very short TTL. The .m4s segments are immutable once published and can be cached longer to offload the origin.

File typePattern (case-insensitive regex)TTLWhy
Manifest (MPD)~* \.(mpd)$2 secondsMust stay fresh; the live presentation advances.
Media segment~* \.(m4s)$10 secondsImmutable within the rolling window.
tip

DASH and HLS share the same caching philosophy: short TTL on the manifest, modest TTL on the segments. If you serve both protocols from one property, use the combined manifest pattern below so a single rule covers .m3u8 and .mpd.

Manifest cache rule​

Use the Regex match type (matchType: 4) so the case-insensitive .mpd pattern applies.

{
  "name": "DASH manifest",
  "pattern": "\\.(mpd)$",
  "matchType": 4,
  "ttlSeconds": 2,
  "description": "Keep DASH manifest fresh",
  "order": 1,
  "isEnabled": true
}
curl -X POST 'https://api.paradarum.com/api/Property/42/rules/cache' \
  -H 'X-Api-Key: pdm_YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{
        "name": "DASH manifest",
        "pattern": "\\.(mpd)$",
        "matchType": 4,
        "ttlSeconds": 2,
        "description": "Keep DASH manifest fresh",
        "order": 1,
        "isEnabled": true
      }'

Segment cache rule​

{
  "name": "DASH segment",
  "pattern": "\\.(m4s)$",
  "matchType": 4,
  "ttlSeconds": 10,
  "description": "Immutable DASH segments",
  "order": 2,
  "isEnabled": true
}
curl -X POST 'https://api.paradarum.com/api/Property/42/rules/cache' \
  -H 'X-Api-Key: pdm_YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{
        "name": "DASH segment",
        "pattern": "\\.(m4s)$",
        "matchType": 4,
        "ttlSeconds": 10,
        "description": "Immutable DASH segments",
        "order": 2,
        "isEnabled": true
      }'
note

The .m4s segment extension is shared by HLS (with fragmented MP4 / CMAF) and DASH. A single segment rule with pattern \.(ts|m4s)$ therefore covers both protocols when you serve them side by side.

Serving HLS and DASH together​

If one property delivers both protocols, collapse the two manifest rules into one with a combined pattern so a single rule keeps every playlist fresh:

{
  "name": "Live manifest (HLS + DASH)",
  "pattern": "\\.(m3u8|mpd)$",
  "matchType": 4,
  "ttlSeconds": 2,
  "description": "Fresh HLS and DASH manifests",
  "order": 1,
  "isEnabled": true
}

This ~* \.(m3u8|mpd)$ pattern is exactly what Paradarum uses for the system manifest rule on managed live properties.

CORS header rule for dash.js​

dash.js loads the manifest and segments over fetch/XHR, so the responses need a permissive CORS header. Add a response header rule with the Set action (action: 1), an empty pattern (global), and applyToRequest: false.

{
  "name": "DASH CORS",
  "pattern": "",
  "matchType": 1,
  "action": 1,
  "headerName": "Access-Control-Allow-Origin",
  "headerValue": "*",
  "applyToRequest": false,
  "order": 3,
  "isEnabled": true
}
curl -X POST 'https://api.paradarum.com/api/Property/42/rules/header' \
  -H 'X-Api-Key: pdm_YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{
        "name": "DASH CORS",
        "pattern": "",
        "matchType": 1,
        "action": 1,
        "headerName": "Access-Control-Allow-Origin",
        "headerValue": "*",
        "applyToRequest": false,
        "order": 3,
        "isEnabled": true
      }'
info

action: 1 is Set/Replace. Use a specific origin instead of * to restrict which sites may embed your dash.js player.

A note on Paradarum Live properties​

When you publish via Paradarum Live, the backing CDN property already carries equivalent system rules: a combined ~* \.(m3u8|mpd)$ manifest rule (TTL 2s), a ~* \.(ts|m4s)$ segment rule (TTL 10s), and an Access-Control-Allow-Origin: * CORS rule. They are read-only on the managed property. Use the templates here only for custom DASH delivery on a standard property. See live playback and caching.

See also​