如何在运行时将 CIFilters 添加到视频

Question

我使用 avfoundation 录制了一个视频，点击视频后，它开始在新的视图控制器上播放。问题是，我无法为正在播放的视频添加滤镜效果。以下是我所实现的代码。

import UIKit
import AVFoundation

class VideoPlayback: UIViewController {

    let avPlayer = AVPlayer()
    var avPlayerLayer: AVPlayerLayer!

    var videoURL: URL!

    @IBOutlet weak var videoView: UIView!

    override func viewDidLoad() {
        super.viewDidLoad()

        NotificationCenter.default.addObserver(self, selector: #selector(finishVideo), name: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: nil)

        avPlayerLayer = AVPlayerLayer(player: avPlayer)
        avPlayerLayer.frame = view.bounds
        avPlayerLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
        videoView.layer.insertSublayer(avPlayerLayer, at: 0)

        view.layoutIfNeeded()

        let playerItem = AVPlayerItem(url: videoURL as URL)
        avPlayer.replaceCurrentItem(with: playerItem)

        avPlayer.play()

    }

    @objc func finishVideo()
        {
            print("Video Finished")
            self.performSegue(withIdentifier: "unwindToFifteenSeconds", sender: self)
        }

// Remove Observer
    deinit {
        NotificationCenter.default.removeObserver(self)
    }

}

上面的代码只是播放一段用AVfoundation 被摄像头拍到的视频。我只需要在这个播放的视频中添加 CIfilters。

Answer 1

您可以对视频应用过滤器

let filter = CIFilter(name: "CIGaussianBlur")!
let asset = AVAsset(url: streamURL)
let item = AVPlayerItem(asset: asset)
item.videoComposition = AVVideoComposition(asset: asset,  applyingCIFiltersWithHandler: { request in

    // Clamp to avoid blurring transparent pixels at the image edges
    let source = request.sourceImage.clampingToExtent()
    filter.setValue(source, forKey: kCIInputImageKey)

    // Vary filter parameters based on video timing
    let seconds = CMTimeGetSeconds(request.compositionTime)
    filter.setValue(seconds * 10.0, forKey: kCIInputRadiusKey)

    // Crop the blurred output to the bounds of the original image
    let output = filter.outputImage!.cropping(to: request.sourceImage.extent)

    // Provide the filter output to the composition
    request.finish(with: output, context: nil)
})