Swift如何将视频和音频合并为一个mp4文件

Question

我想将AVCaptureSession（）捕获的视频和AVAudioRecorder（）录制的音频合并为一个mp4文件。

我试过这个解决方案 Swift Merge audio and video files into one video

和Merging audio and video Swift

但他们两个都没有用。他们都给了我同样的错误：Thread1：Signal SIGABRT

那么合并音频和视频的正确方法是什么？

更新： -

我发现每次应用崩溃的地方。它在试图从 AVAsset

获取 AVAssetTrack 的代码行崩溃

func merge(audio:URL, withVideo video : URL){

    // create composition
    let mutableComposition = AVMutableComposition()

    // Create the video composition track.
    let mutableCompositionVideoTrack : AVMutableCompositionTrack = mutableComposition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: kCMPersistentTrackID_Invalid)

    // Create the audio composition track.
    let mutableCompositionAudioTrack : AVMutableCompositionTrack = mutableComposition.addMutableTrack(withMediaType: AVMediaTypeAudio, preferredTrackID: kCMPersistentTrackID_Invalid)

    // create media assets and tracks
    let videoAsset = AVAsset(url: video)  
    let videoAssetTrack = videoAsset.tracks(withMediaType: AVMediaTypeVideo)[0] // ** always crashes here ** //

    let audioAsset = AVAsset(url: audio) 
    let audioAssetTrack = audioAsset.tracks(withMediaType: AVMediaTypeAudio)[0] // ** always crashes here ** //

....

}