[英]Loop audio for certain duration on iOS
我想知道在iOS上定義的持續時間內循環播放音頻的最佳解決方案是什么。 我目前正在和
AVAudioPlayer
(我可以在其中定義重復計數,但不能定義結束時間) AVPlayer
(我可以在其中定義forwardPlaybackEndTime
機器人,而不是循環計數) AVPlayerLooper
(我尚未完全理解) 因此,我需要定義一個重復某些聲音文件的持續時間。 Fe我有一個8秒的mp3,想播放一分鍾。
如果我能再次淡入淡出,suuuuper也將很棒。
您使用AVPlayerLooper處於正確的軌道。
這是設置AVPlayerLooper
var playerLooper: AVPlayerLooper!
var player: AVQueuePlayer!
func play(_ url: URL) {
let asset = AVAsset(url: url)
let playerItem = AVPlayerItem(asset: asset)
player = AVQueuePlayer(playerItem: playerItem)
playerLooper = AVPlayerLooper(player: player, templateItem: playerItem)
player.play()
}
要在設置的時間后停止循環,可以使用addBoundaryTimeObserver(forTimes:queue:using :)例如:
let assetDuration = CMTimeGetSeconds(asset.duration)
let maxDuration = 60.0 // Define max duration
let maxLoops = floor(maxDuration / assetDuration)
let lastLoopDuration = maxDuration - (assetDuration * maxLoops)
let boundaryTime = CMTimeMakeWithSeconds(lastLoopDuration, preferredTimescale: 1)
let boundaryTimeValue = NSValue(time: boundaryTime)
player.addBoundaryTimeObserver(forTimes: [boundaryTimeValue], queue: DispatchQueue.main) { [weak self] in
if self?.playerLooper.loopCount == Int(maxLoops) {
self?.player.pause()
}
}
為了淡入/淡出,必須在使用前將audioMix
屬性設置為AVPlayerItem
實例。
let introRange = CMTimeRangeMake(start: CMTimeMakeWithSeconds(0, preferredTimescale: 1), duration: CMTimeMakeWithSeconds(1, preferredTimescale: 1))
let endingSecond = CMTimeRangeMake(start: CMTimeMakeWithSeconds(assetDuration - 1, preferredTimescale: 1), duration: CMTimeMakeWithSeconds(1, preferredTimescale: 1))
let inputParams = AVMutableAudioMixInputParameters(track: asset.tracks.first! as AVAssetTrack)
inputParams.setVolumeRamp(fromStartVolume: 0, toEndVolume: 1, timeRange: introRange)
inputParams.setVolumeRamp(fromStartVolume: 1, toEndVolume: 0, timeRange: endingSecond)
let audioMix = AVMutableAudioMix()
audioMix.inputParameters = [inputParams]
playerItem.audioMix = audioMix
完整功能:
func play(_ url: URL) {
let asset = AVAsset(url: url)
let playerItem = AVPlayerItem(asset: asset)
let assetDuration = CMTimeGetSeconds(asset.duration)
let introRange = CMTimeRangeMake(start: CMTimeMakeWithSeconds(0, preferredTimescale: 1), duration: CMTimeMakeWithSeconds(1, preferredTimescale: 1))
let endingSecond = CMTimeRangeMake(start: CMTimeMakeWithSeconds(assetDuration - 1, preferredTimescale: 1), duration: CMTimeMakeWithSeconds(1, preferredTimescale: 1))
let inputParams = AVMutableAudioMixInputParameters(track: asset.tracks.first! as AVAssetTrack)
inputParams.setVolumeRamp(fromStartVolume: 0, toEndVolume: 1, timeRange: introRange)
inputParams.setVolumeRamp(fromStartVolume: 1, toEndVolume: 0, timeRange: endingSecond)
let audioMix = AVMutableAudioMix()
audioMix.inputParameters = [inputParams]
playerItem.audioMix = audioMix
player = AVQueuePlayer(playerItem: playerItem)
playerLooper = AVPlayerLooper(player: player, templateItem: playerItem)
player.play()
let maxDuration = 60.0 // Define max duration
let maxLoops = floor(maxDuration / assetDuration)
let lastLoopDuration = maxDuration - (assetDuration * maxLoops)
let boundaryTime = CMTimeMakeWithSeconds(lastLoopDuration, preferredTimescale: 1)
let boundaryTimeValue = NSValue(time: boundaryTime)
player.addBoundaryTimeObserver(forTimes: [boundaryTimeValue], queue: DispatchQueue.main) { [weak self] in
if self?.playerLooper.loopCount == Int(maxLoops) {
self?.player.pause()
}
}
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.