💾

Offline Playback and Cache Management

Help Article

Browser Cache Principles

Browser cache is an important mechanism for improving M3U8 playback performance:

Cache Workflow
  • Browser stores video segments locally after downloading
  • Reads directly from cache when playing same segments again
  • Reduces network requests, improves loading speed
  • Saves bandwidth consumption
Cache Storage Locations
  • Memory Cache: Temporarily stored in memory, cleared after closing tab
  • Disk Cache: Stored on hard drive, can persist
  • IndexedDB: Browser database, suitable for storing large amounts of data
Cache Strategies
  • Cache-Control: Server controls cache via HTTP headers
  • Expires: Sets cache expiration time
  • ETag: Used to verify if cache is valid

Service Worker Offline Support

Service Worker can implement more powerful offline playback functionality:

Service Worker Introduction
  • Script running in browser background
  • Can intercept network requests
  • Implements offline caching functionality
  • Supports background synchronization
Offline Cache Implementation
  • Register Service Worker
  • Pre-cache video segments during installation
  • Intercept requests, prioritize reading from cache
  • Fetch from network when cache miss
Usage Limitations
  • Requires HTTPS environment (except localhost)
  • Requires browser support for Service Worker API
  • Cache size limited by browser

Cache Strategy Selection

Different cache strategies are suitable for different scenarios:

Cache First
  • Prioritize using cache, request network when cache miss
  • Suitable for content that doesn't update frequently
  • Can play completely offline
Network First
  • Prioritize requesting network, use cache when failed
  • Suitable for situations requiring latest content
  • Ensures content freshness when network is available
Hybrid Strategy (Stale-While-Revalidate)
  • Immediately return cached content
  • Update cache in background
  • Balances speed and freshness

Cache Size Management

Properly manage cache size to avoid occupying too much storage space:

Browser Cache Limits
  • Different browsers have different cache size limits
  • Chrome: Usually 20% of available disk space
  • Firefox: Can configure cache size limit
  • Safari: Automatically manages based on available space
Cache Cleanup Strategies
  • Time Strategy: Regularly clean expired cache
  • Size Strategy: Clean oldest when cache reaches limit
  • LRU Strategy: Clean least recently used cache
Manual Management
  • Regularly clean browser cache
  • Use browser settings to manage cache size
  • Clear cache for specific websites

Cache Cleanup Methods

Cleaning cache can free storage space and solve some issues:

Browser Settings Cleanup
  • Chrome: Settings → Privacy and Security → Clear Browsing Data → Cached Images and Files
  • Firefox: Settings → Privacy & Security → Cookies and Site Data → Clear Data
  • Safari: Preferences → Advanced → Show Develop Menu → Empty Caches
Developer Tools Cleanup
  • Open Developer Tools (F12)
  • Application tab → Storage → Clear site data
  • Can clear specific types of cache
Command Line Cleanup
  • Some browsers support command line parameters to clean cache
  • Suitable for batch operations or automation scripts

Offline Playback Implementation

Implement offline playback for M3U8 videos:

Pre-download Method
  • Download all video segments when online
  • Store to browser cache or IndexedDB
  • Read from local storage when offline
Using Download Tools
  • Use download tools that support M3U8
  • Convert to MP4 format after downloading
  • Play using local player
PWA Application
  • Package player as PWA application
  • Use Service Worker to implement offline functionality
  • Support adding to home screen

Storage Space Optimization

Optimize storage space usage:

Compressed Storage
  • Use compression algorithms to reduce storage space
  • Balance compression ratio and decompression speed
  • Consider device performance
Selective Caching
  • Only cache commonly used video segments
  • Prioritize caching key segments
  • Regularly clean unused cache
External Storage
  • Use external storage devices
  • Mobile devices can use SD cards
  • Desktop devices can use external hard drives

Cache Best Practices

  • Set Reasonable Cache Size: Set appropriate cache limit based on device storage space
  • Regular Cleanup: Regularly clean expired and unused cache
  • Monitor Usage: Regularly check cache usage
  • Optimize Cache Strategy: Choose most suitable cache strategy based on usage scenarios
  • Consider User Experience: Find balance between cache and storage space

Common Questions

Q: Cache occupies too much space?

A: Regularly clean browser cache, or limit cache size in browser settings. Can also use incognito mode to avoid cache accumulation.

Q: How to achieve completely offline playback?

A: Need to pre-download all video segments. Can use download tools to convert to MP4, or use player applications that support offline caching.

Q: Cache causes playback of old content?

A: Clear browser cache, or use force refresh (Ctrl+F5) to reload content. Can also use incognito mode to avoid cache issues.

By properly managing cache, you can improve playback speed, save bandwidth, and to some extent achieve offline playback functionality.

← Back to Articles