Swift:尝试使用UISlider控制AVAudioPlayerNode中的时间 [英] Swift: Trying to control time in AVAudioPlayerNode using UISlider

问题描述

我正在使用连接到 AVAudioEngine 的 AVAudioPlayerNode 播放声音.

I'm using an AVAudioPlayerNode attached to an AVAudioEngine to play a sound.

要获取我正在执行的播放器的当前时间:

to get the current time of the player I'm doing this:

extension AVAudioPlayerNode {
var currentTime: TimeInterval {
    get {
        if let nodeTime: AVAudioTime = self.lastRenderTime, let playerTime: AVAudioTime = self.playerTime(forNodeTime: nodeTime) {
            return Double(playerTime.sampleTime) / playerTime.sampleRate
        }
        return 0
    }
 }

}

我有一个指示音频当前时间的滑块.当用户更改滑块值时，在 .ended 事件上，我必须将播放器的当前时间更改为滑块中指示的时间.为此:

I have a slider that indicates the current time of the audio. When the user changes the slider value, on .ended event I have to change the current time of the player to that indicated in the slider. To do so:

extension AVAudioPlayerNode {

func seekTo(value: Float, audioFile: AVAudioFile, duration: Float) {
    if let nodetime = self.lastRenderTime{
        let playerTime: AVAudioTime = self.playerTime(forNodeTime: nodetime)!
        let sampleRate = self.outputFormat(forBus: 0).sampleRate
        let newsampletime = AVAudioFramePosition(Int(sampleRate * Double(value)))
        let length = duration - value
        let framestoplay = AVAudioFrameCount(Float(playerTime.sampleRate) * length)
        self.stop()

        if framestoplay > 1000 {
            self.scheduleSegment(audioFile, startingFrame: newsampletime, frameCount: framestoplay, at: nil,completionHandler: nil)
        }
    }
    self.play()
}

但是，我的函数 seekTo 无法正常工作(我在函数前后打印currentTime，并且始终显示负值〜= -0.02).我在做什么错了，我可以找到一种更简单的方法来更改播放器的currentTime吗?

However, my function seekTo is not working correctly(I'm printing currentTime before and after the function and it shows always a negative value ~= -0.02). What is the wrong thing I'm doing and can I find a simpler way to change the currentTime of the player?

推荐答案

我遇到了同样的问题.显然， framestoplay 始终为0，这是由于 sampleRate 导致的.在我的情况下， playerTime.sampleRate 的值始终为0.

I ran into same issue. Apparently the framestoplay was always 0, which happened because of sampleRate. The value for playerTime.sampleRate was always 0 in my case.

所以

let framestoplay = AVAudioFrameCount(Float(playerTime.sampleRate) * length)

必须替换为

let framestoplay = AVAudioFrameCount(Float(sampleRate) * length)

这篇关于Swift:尝试使用UISlider控制AVAudioPlayerNode中的时间的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！