如果您使用AVMutableComposition创建视频并遇到间歇性静音问题，则很可能是由于您的AVAssetTrack中的音频配置不正确而引起的。

以下是一个可能的解决方案，可以检查您的音频配置是否正确：

let composition = AVMutableComposition()
let videoTrack = composition.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)
let audioTrack = composition.addMutableTrack(withMediaType: .audio, preferredTrackID: kCMPersistentTrackID_Invalid)

// Add your video and audio assets to each track

if let audioAssetTrack = audioAsset.tracks(withMediaType: .audio).first {
    do {
        let audioInputParams = AVMutableAudioMixInputParameters(track: audioTrack)
        let audioTimeRange = CMTimeRangeMake(start: .zero, duration: audioAssetTrack.timeRange.duration)
        try audioInputParams.setVolume(1.0, at: .zero)
        try audioInputParams.setAudioTimePitchAlgorithm(AVAudioTimePitchAlgorithm.timeDomain)
        audioInputParams.audioTimePitchAlgorithm = .varispeed
        try audioInputParams.setAudioMix(myAudioMixes, at: .zero)
        audioInputParams.trackID = audioTrack.trackID
        if let audioMix = AVMutableAudioMix() {
            audioMix.inputParameters = [audioInputParams]
            let exportSession = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetHighestQuality)
            exportSession?.audioMix = audioMix
            exportSession?.timeRange = videoTrack.timeRange
            exportSession?.outputFileType = .mov
            ...
        }
    } catch {
        print("Error setting up audio input params: \(error)")
    }
}

这里我们使用AVMutableAudioMixInputParameters配置音频轨道，设置音量、时间和音高算法，并将其应用于AVMutableComposition。请注意，您需要确保设置的音频参数与您的音频资源匹配，以避免静音问题。