How to Playback an M3U8 Video from Cache in iOS?

Are you tired of buffering and lagging while playing M3U8 videos in your iOS app? Do you want to provide a seamless video playback experience to your users? Then, you’re in the right place! In this article, we’ll dive into the world of M3U8 video caching and explore the steps to playback an M3U8 video from cache in iOS.

What is M3U8?

M3U8 is a format used for describing playlists for multimedia files, such as videos. It’s a Unicode version of the M3U format and is widely used in streaming media applications. M3U8 files contain a list of URLs that point to the actual video files, along with additional metadata like video title, description, and thumbnail.

Why Cache M3U8 Videos?

Caching M3U8 videos can significantly improve the playback experience in iOS apps. Here are some reasons why:

• Faster Playback**: Caching reduces the latency and buffering time, allowing users to start playing the video quickly.
• Reduced Data Consumption**: By storing the video in the cache, you can reduce the amount of data consumed by the user, making it more cost-effective.
• Offline Playback**: Caching enables offline playback, allowing users to watch videos even when they don’t have an internet connection.

Setting Up the Project

Before we dive into the caching part, let’s set up an iOS project that can play M3U8 videos. Create a new iOS project in Xcode, and add the following frameworks:

  
import UIKit
import AVFoundation
  

Next, create a new Swift file and add the following code to create a basic AVPlayer instance:

  
import Foundation
import AVFoundation

class VideoPlayer {
  let player = AVPlayer()

  func play(url: URL) {
    let playerItem = AVPlayerItem(url: url)
    player.replaceCurrentItem(with: playerItem)
    player.play()
  }
}
  

Caching M3U8 Videos

To cache M3U8 videos, we’ll use a combination of URL caching and manual caching using the `FileManager`. We’ll also use a third-party library called `SwiftCache` to simplify the caching process.

Step 1: Install SwiftCache

Open your project in Xcode, and add SwiftCache using the following command in the terminal:

  
pod 'SwiftCache'
  

Install the pod by running `pod install`.

Step 2: Configure URL Caching

In your `VideoPlayer` class, add the following code to configure URL caching:

  
import SwiftCache

let cache = Cache(diskConfig: DiskConfig(name: "VideoCache"))

func cacheConfiguration() {
  let cachePolicy = URLCache.CachePolicy.returnCacheDataElseLoad
  URLCache.shared.cachePolicy = cachePolicy
}
  

Here, we’re creating a `Cache` instance with a disk config named “VideoCache”. We’re also setting the cache policy to `returnCacheDataElseLoad`, which means the cache will return cached data if available, and load from the network if not.

Step 3: Cache M3U8 Playlist

When the user requests an M3U8 video, we’ll cache the playlist and its associated video segments. Add the following code to your `VideoPlayer` class:

  
func cacheM3U8Playlist(url: URL) {
  let task = URLSession.shared.dataTask(with: url) { [weak self] data, response, error in
    if let error = error {
      print("Error caching M3U8 playlist: \(error)")
      return
    }

    guard let data = data else { return }
    let m3u8String = String(data: data, encoding: .utf8) ?? ""

    // Parse the M3U8 playlist and extract the video segments
    let parser = M3U8Parser()
    let playlist = parser.parse(m3u8String)

    // Cache the video segments
    playlist.segments.forEach { segment in
      let segmentURL = url.appendingPathComponent(segment.uri)
      self?.cacheVideoSegment(url: segmentURL)
    }
  }
  task.resume()
}
  

Here, we’re creating a `URLSession` task to download the M3U8 playlist. Once downloaded, we parse the playlist using an `M3U8Parser` instance, and extract the video segments. We then cache each video segment using the `cacheVideoSegment` method.

Step 4: Cache Video Segments

Add the following code to your `VideoPlayer` class to cache video segments:

  
func cacheVideoSegment(url: URL) {
  let task = URLSession.shared.dataTask(with: url) { [weak self] data, response, error in
    if let error = error {
      print("Error caching video segment: \(error)")
      return
    }

    guard let data = data else { return }
    self?.cache.set(value: data, forKey: url)
  }
  task.resume()
}
  

Here, we’re creating a `URLSession` task to download the video segment. Once downloaded, we cache the segment using the `Cache` instance.

Playback from Cache

Now that we’ve cached the M3U8 playlist and video segments, let’s modify the `play` method to playback from cache:

  
func play(url: URL) {
  if let cachedData = cache.get(forKey: url) {
    // Create an AVAsset from the cached data
    let asset = AVAsset(url: url)
    let playerItem = AVPlayerItem(asset: asset)
    player.replaceCurrentItem(with: playerItem)
    player.play()
  } else {
    // Download and play from the network
    cacheM3U8Playlist(url: url)
  }
}
  

Here, we’re checking if the video segment is cached by calling `cache.get(forKey: url)`. If it’s cached, we create an `AVAsset` from the cached data and play it using the `AVPlayer` instance. If not, we download the video segment from the network using the `cacheM3U8Playlist` method.

Conclusion

That’s it! You’ve now successfully implemented M3U8 video caching in your iOS app. By following these steps, you can provide a seamless video playback experience to your users, reduce data consumption, and enable offline playback.

Troubleshooting Tips

If you encounter any issues during implementation, here are some troubleshooting tips:

• Check the cache directory**: Verify that the cache directory is created and the video segments are being stored correctly.
• Verify the M3U8 playlist**: Ensure that the M3U8 playlist is being parsed correctly and the video segments are being extracted correctly.
• Check the network requests**: Verify that the network requests are being made correctly and the video segments are being downloaded successfully.

Question	Answer
How do I cache M3U8 videos in iOS?	Use a combination of URL caching and manual caching using the `FileManager` and a third-party library like SwiftCache.
What is the benefit of caching M3U8 videos?	Caching reduces latency, data consumption, and enables offline playback, providing a seamless video playback experience to users.
How do I playback an M3U8 video from cache?	Check if the video segment is cached, and if so, create an `AVAsset` from the cached data and play it using the `AVPlayer` instance.

By following these steps and troubleshooting tips, you’ll be able to playback M3U8 videos from cache in your iOS app, providing an exceptional user experience.

Frequently Asked Question

Get ready to dive into the world of iOS video playback from cache!