快速更改帧频后保存avplayer视频

Question

我正在将视频的帧频更改为快进和快退视频，但是在迅速更改帧频后如何将视频保存到照片库中。

Answer 1

所以我通过以下代码解决了这个问题：-

 let videoAsset = AVAsset(url: inputURL as URL) as AVAsset
    let clipVideoTrack = videoAsset.tracks(withMediaType: AVMediaType.video).first! as AVAssetTrack

    let composition = AVMutableComposition()
let videoCompositions = composition.addMutableTrack(withMediaType: AVMediaType.video, preferredTrackID: CMPersistentTrackID())
    do {
        try videoCompositions?.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration), of: (videoAsset.tracks(withMediaType: AVMediaType.video).first)!, at: kCMTimeZero)
    } catch {
        print("handle insert error")
        return
    }
let videoDuration = videoAsset.duration
    let finalTimeScale:Int64 = (Int64(float_t(videoDuration.value) / player.rate))
    print("player rate is",player.rate)
    videoCompositions?.scaleTimeRange(CMTimeRangeMake(kCMTimeZero, videoDuration), toDuration: CMTimeMake(finalTimeScale, videoDuration.timescale))
let fileManager = FileManager.default
    let documentDirectory = fileManager.urls(for: .documentDirectory, in: .userDomainMask)[0]
    var outputURL = documentDirectory.appendingPathComponent("output")
    do {

        try fileManager.createDirectory(at: outputURL, withIntermediateDirectories: true, attributes: nil)
        outputURL = outputURL.appendingPathComponent("\(String(describing: inputURL.lastPathComponent)).mp4")
    }catch let error {
        print(error)
    }
    try? fileManager.removeItem(at: outputURL)

     guard let exporter = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetHighestQuality) else { return }
exporter.outputURL = outputURL
    exporter.outputFileType = .mp4
    exporter.exportAsynchronously {
        switch exporter.status {
        case .completed:
            print("exported at \(outputURL)")
            completion?(outputURL)
            UISaveVideoAtPathToSavedPhotosAlbum(outputURL.path,nil, nil, nil)
        case .failed:
            print("failed \(exporter.error.debugDescription)")
        case .cancelled:
            print("cancelled \(exporter.error.debugDescription)")
        default: break
        }
    }