在iOS上使用AVAudioPlayer播放静音的最佳方法

由 发布于 iosswiftavaudioplayeravkit
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I found myself in a situation where I need to simulate audio playback to trick OS controls and MPNowPlayingInfoCenter into thinking that an audio is being played. This is because I am building a player that plays multiple audio tracks, with pauses in-between creating one, continuous "audio" track. I have already everything setup inside the app itself, and the lock screen controls are working correctly but the only problem I am facing is while the actual audio stops and a pause is being "played", the lock screen info center stops the timer, and it only continues with showing correct time and overall state once another audio track starts playing.

这是根据音频文件和暂停项目构建的音频轨道的示例：

let items: [AudioItem] = [
    .audio("part-1.mp3"),
    .pause(duration: 5), // value of type: TimeInterval
    .audio("part-2.mp3"),
    .pause(duration: 3),
    ... // the list goes on
]

then in my custom player, once AVAudioPlayer finishes its job with current item, I get the next one from the array and play either a .pause with a scheduled Timer or another .audio with AVAudioPlayer.

extension Player: AVAudioPlayerDelegate {
    func audioPlayerDidFinishPlaying(_ player: AVAudioPlayer, successfully flag: Bool) {
        playNextItem()
    }
}

And here lies the problem, once the AVAudioPlayer stops, the Now Playing info center automatically stops too, even tho I keep feeding it fresh nowPlayingInfo. Then when it hits another .audio item, it resumes correctly and shows current time, etc.

问题就在这里

how do I trick the MPNowPlayingInfoCenter into thinking that audio is being played while I "play" my .pause item?

我意识到可能尚不清楚我要实现的目标，但很高兴在需要时分享更多见解。谢谢！

我目前正在考虑的一些解决方案：

A.保持1s较长的空音频轨道，只要需要播放暂停，它就会循环播放。

B. Creating programatically empty audio track with appropriate lenght and playing it instead of using Timer for keeping track of pause duration/progress and relying completely on AVAudioPlayer for both .audio and .pause items. Not sure this is possible though.

C. Maybe there is a way to tell the MPNowPlayingInfoCenter that the audio keeps playing without the need of using AVAudioPlayer but some API I am not familiar with?

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