问如何在m3u8视频流中切换音轨？

EN

let mediaSelectionGroup = self.player!.currentItem!.asset.mediaSelectionGroup(forMediaCharacteristic: AVMediaCharacteristicAudible)!
        print("ASSET AUDIO TRACKS: \(mediaSelectionGroup)")

self.mediaSelectionOptions = Dictionary<String, AVMediaSelectionOption>()

    for mediaSelectionOption in self.mediaSelectionGroup!.options {
        if let locale = mediaSelectionOption.locale, let languageCode = locale.languageCode {
            if languageCode == "en" {
                self.mediaSelectionOptions!["Inglés"] = mediaSelectionOption
            } else if languageCode == "es" {
                self.mediaSelectionOptions!["Español"] = mediaSelectionOption
            }
        }
    }

// Set Spanish audio
self.player!.currentItem!.select(
                self.audioManager!.mediaSelectionOptions!["Español"],
                in: mediaSelectionGroup
            )

// Set English audio
self.player!.currentItem!.select(
                self.audioManager!.mediaSelectionOptions!["Inglés"],
                in: mediaSelectionGroup
            )