Preface ：

Recently, the work content uses voice playback , from AVPlayer To AVPlayerItem, I encountered a lot of problems , A lot bug, Also summarized some experience . Yes AVPlayer Learn more , Because there are many points involved , So I'm going to make a series and write this part in detail . I hope you can support me more , If you have any problems, please correct me .

AVPlayer Is a full-featured video player that can play any format
Support video format : WMV,AVI,MKV,RMVB,RM,XVID,MP4,3GP,MPG etc. .
Support audio format ：MP3,WMA,RM,ACC,OGG,APE,FLAC,FLV etc. .
So I have to say that Apple's son is still very powerful , Is the first choice for video development .

How to use

AVPlayer Exist in AVFoundation frame , We need to import :

import AVFoundation

Several playback related parameters ( For the time being, I'll just talk about what I use )

Before creating a player, we need to know some player related classes

AVPlayer: Control the playback of the player , Pause , Broadcasting speed
AVPlayerItem: Manage resource objects , Provide playback data source

1. establish AVPlayer

Because I play , Need to play 、 Pause 、 Replay 、 Drag the progress bar to play , So I used AVPlayerItem

if let url = URL(string: "http://img.youluwx.com/qa/20200917/video/c94869f4-0ddc-4e45-be7e-b0620acc544d.mp3") {
     
    let playerItem = AVPlayerItem(url: url) 
    let play = AVPlayer(playerItem: playerItem)
}

1.2 Video playback 、 Pause

/// Play 
player.play()
/// Pause 
player.pause()

1.3 Replay

Replay is , First adjust the progress to the beginning , And then play

let seekTime = CMTime(value: CMTimeValue(0), timescale: 1)
player.seek(to: seekTime, completionHandler: {
     _ in
                        
})
player.play()

1.3 Drag the progress bar to play

Use here UISlider Slide bar to drag and use Swift Use UISlider

let playTime = slider.value * duration
let seekTime = CMTime(value: CMTimeValue(playTime), timescale: 1)
player.seek(to: seekTime, completionHandler: {
     _ in
                        
})

1.4 Playback progress monitoring

let playerItem = AVPlayerItem(url: url)
let player = AVPlayer(playerItem: playerItem)
player.addPeriodicTimeObserver(forInterval: CMTime(value: 1, timescale: 1), queue: DispatchQueue.main) {
     time in
	if let duration = self.playerItem?.duration {
    
    	let nowDuration = CMTimeGetSeconds(duration)
    	let currentTime = Int(time.seconds)
    	
    	let text = "\(currentTime)/\(nowDuration)\""
    	let progress = Float(currentTime) / Float(nowDuration)
     	print("text:\(text) progress:\(progress)") 
    } 
}

2. Problems encountered

2.1 Get the total time of network audio

Use AVPlayer Play network streaming media , Found a pit ：
Namely playerItem.duration It is possible not to return the total playing time of the network multimedia resources , Instead, it returns a strange data :nan,
Because I passed CMTimeGetSeconds (playerItem.duration) What you get has always been nan, Only monitor the playback progress , You can't get the data until you start playing

let playerItem = AVPlayerItem(url: url)
if let duration = playerItem?.duration {
    
       print(CMTimeGetSeconds(duration))
}

After many twists and turns , Find out CMTimeGetSeconds (playerItem.asset.duration) What is returned is the correct total playing time of the network multimedia resource .

let playerItem = AVPlayerItem(url: url)
if let duration = playerItem?.asset.duration {
     
     print(CMTimeGetSeconds(duration))
}

Last , The total time may be a little less than the playback time , This has never been understood , If you know something, please leave a message

The biggest problem

During the final test , Encountered more serious problems , I found that part of our voice can play , The other part cannot be played ,
Playable voice

http://img.youluwx.com/qa/20200917/video/c94869f4-0ddc-4e45-be7e-b0620acc544d.mp3

Do not play voice

http://img.youluwx.com/qa/20201110/video/47e36af4-8fc2-432f-b7c6-ccd982140694.mp3

I downloaded the audio files separately and compared them ：

Can't play in Safari Open in the browser and display as follows , What can be played will not be displayed for the time being

The specific reason should be AVPlayer Don't support it , As for more specific questions ： Maybe it's because I'm too delicious , Can't find the problem , No concrete solution has been found , Can only borrow other video players for temporary use
Um. , Last , If you want to use it AVPlayer, Better be careful