Optimize CDN caching for MediaTailor and MediaPackage content delivery - AWS Elemental MediaTailor
MediaPackage cache-control headersConfigure CDN cache policiesOptimize query string forwardingPerformance optimization techniquesMonitor cache performance

Optimize CDN caching for MediaTailor and MediaPackage content delivery

AWS Elemental MediaTailor requires proper content delivery network (CDN) caching configuration for optimal performance when using AWS Elemental MediaPackage as your content origin. MediaPackage provides specific cache-control headers that tell your content delivery network how long to cache different types of content. Following these recommendations ensures smooth playback and efficient content delivery.

This topic focuses specifically on optimizing caching behavior to maximize performance and minimize costs. Before implementing advanced caching optimization, ensure you have completed the basic content delivery network integration setup. If you haven't set up your basic integration yet, start with Integrate MediaTailor with MediaPackage and CDN .

MediaPackage cache-control headers

MediaPackage sets specific TTL values for different content types to optimize caching behavior:

Multivariant playlists (HLS and LL-HLS)

TTL: Half the duration of the media segments

Reason: These playlists change as new segments become available, so they need frequent updates

Media playlists (regular HLS)

TTL: Half the duration of the media segments

Reason: Similar to multivariant playlists, these update as content progresses

Media playlists (LL-HLS)

TTL: 1 second

Reason: Low-latency streaming requires very frequent updates

TS media segments and init segments

TTL: 1209600 seconds (14 days)

Reason: Media segments don't change once created, so they can be cached for extended periods

CMAF media segments and initialization segments

TTL: 1209600 seconds (14 days)

Reason: Like TS segments, these are immutable once created

For comprehensive TTL recommendations across all MediaTailor workflows and additional caching optimization strategies, see Caching optimization for CDN and MediaTailor integrations.

Configure CDN cache policies

Proper cache policy configuration is essential for optimal performance and cost efficiency. Different types of content (manifests, segments, initialization files) have different caching requirements. Using separate cache behaviors allows you to optimize caching for each content type, improving cache hit ratios and reducing origin load. Without proper cache policies, you might experience unnecessary origin requests, increased costs, and poor playback performance.

To properly honor MediaPackage cache-control headers and optimize caching:

  1. Open your CloudFront distribution settings in the CloudFront console.

  2. Create separate cache behaviors for different content types:

    • Manifest requests (*.m3u8, *.mpd)

    • Media segments (*.ts, *.mp4, *.m4s)

    • Initialization segments

  3. For each cache behavior, create or select a cache policy with these settings:

    • Enable "Origin Cache-Control Headers" option

    • Set "Origin request policy" to forward necessary headers

    • Configure query string forwarding based on content type

Manifest cache behavior

For manifest requests (*.m3u8, *.mpd):

Media segment cache behavior

For media segments (*.ts, *.mp4, *.m4s):

  • Path pattern: *.ts, *.mp4, *.m4s

  • Cache policy: Honor origin cache-control headers (14-day TTL)

  • Query strings: None (segments don't use query parameters)

  • Compression: Enable for improved delivery performance

Optimize query string forwarding

Query string optimization is critical for cache efficiency because unnecessary query parameters create multiple cache variations for the same content. Each unique query parameter combination creates a separate cache entry, which reduces cache hit ratios and increases origin requests. By forwarding only the query strings that MediaPackage actually uses, you maximize cache efficiency while maintaining full functionality.

Configure your CDN to forward only the query strings that MediaPackage uses, improving cache efficiency:

Essential query strings

start and end - For time-shifted viewing windows

time_delay - For applying time delay on manifest contents

_HLS_msn, _HLS_m, and _HLS_part - For LL-HLS playback requests

Feature-specific query strings

aws.manifestfilter - For manifest filtering

Important

Do not include any other query strings in your cache key. MediaPackage ignores unrecognized parameters, and including them reduces cache efficiency by creating unnecessary cache variations.

Performance optimization techniques

These optimizations are configured on your CDN (such as CloudFront), not in MediaPackage or MediaTailor. Implement these additional optimizations to maximize cache performance:

Origin shield

Origin shield provides an additional caching layer between your CDN edge locations and MediaPackage endpoints. This reduces the number of requests that reach your MediaPackage endpoints, which can improve performance and reduce costs, especially during traffic spikes or when cache hit ratios are lower than optimal. Origin shield is particularly beneficial for live streaming where multiple edge locations might request the same content simultaneously.

Enable origin shield to reduce load on your MediaPackage endpoints:

  1. In your CloudFront distribution, enable Origin Shield for your MediaPackage origin.

  2. Select an origin shield region close to your MediaPackage endpoint.

  3. This creates an additional caching layer that reduces requests to MediaPackage.

Compression configuration

Enable compression for text-based responses:

Monitor cache performance

Track these key metrics to ensure optimal cache performance:

Cache hit ratio

Target: 90% or greater for media segments, 70% or greater for manifests

Low ratios might indicate incorrect TTL settings or unnecessary query parameters

Origin request volume

Monitor requests reaching MediaPackage endpoints

High volumes might indicate caching issues

Cache key variations

Review cache key patterns to identify unnecessary variations

Too many variations reduce cache efficiency

After implementing these cache optimizations, set up monitoring to track their effectiveness. For guidance on monitoring cache hit ratios, origin request patterns, and other key performance metrics, see Monitor performance for MediaPackage, CDN, and MediaTailor integrations. If you observe poor cache performance or unexpected origin requests, see Troubleshoot MediaPackage, CDN, and MediaTailor integrations for troubleshooting steps.