录制视频时的音频音量

Question

经过大量的搜索，我终于找到了允许背景音频在录制视频时播放的代码块，以下是该代码块。

fileprivate func setBackgroundAudioPreference() {
    guard allowBackgroundAudio == true else {
        return
    }

    guard audioEnabled == true else {
        return
    }

    do{
        if #available(iOS 10.0, *) {
            try AVAudioSession.sharedInstance().setCategory(.playAndRecord, mode: .default, options: [.mixWithOthers, .allowBluetooth, .allowAirPlay, .allowBluetoothA2DP])
        } else {
            let options: [AVAudioSession.CategoryOptions] = [.mixWithOthers, .allowBluetooth]
            let category = AVAudioSession.Category.playAndRecord
            let selector = NSSelectorFromString("setCategory:withOptions:error:")
            AVAudioSession.sharedInstance().perform(selector, with: category, with: options)
        }
        try AVAudioSession.sharedInstance().setActive(true)
        session.automaticallyConfiguresApplicationAudioSession = false
    }
    catch {
        print("[SwiftyCam]: Failed to set background audio preference")

    }
}

然而，我有一个小问题。某种原因导致相机加载时背景音频音量降低。当我使用 Instagram 录制视频时，音频不会被降低，并且仍然录制。有没有办法更改我的当前代码块，使其在录制视频时不降低音量？

我阅读了文档，显然 .duckOthers 选项应该是唯一降低音量的选项。但这个选项也会降低音量。

- Bo Jackson

Answer 1

好的，我在深入查阅一些文档后找到了答案。

下面是更新后的代码。您只需要设置 .defaultToSpeaker 选项即可。

fileprivate func setBackgroundAudioPreference() {
    guard allowBackgroundAudio == true else {
        return
    }

    guard audioEnabled == true else {
        return
    }

    do{
        if #available(iOS 10.0, *) {
            try AVAudioSession.sharedInstance().setCategory(.playAndRecord, mode: .default, options: [.mixWithOthers, .allowBluetooth, .allowAirPlay, .allowBluetoothA2DP,.defaultToSpeaker])
        } else {
            let options: [AVAudioSession.CategoryOptions] = [.mixWithOthers, .allowBluetooth]
            let category = AVAudioSession.Category.playAndRecord
            let selector = NSSelectorFromString("setCategory:withOptions:error:")
            AVAudioSession.sharedInstance().perform(selector, with: category, with: options)
        }
        try AVAudioSession.sharedInstance().setActive(true)
        session.automaticallyConfiguresApplicationAudioSession = false
    }
    catch {
        print("[SwiftyCam]: Failed to set background audio preference")

    }
}

- Bo Jackson