iOS开发 视频去水印

iOS开发 视频去水印

在现代社交媒体的普及下，越来越多的人开始使用视频去水印应用来去除视频中的水印。本文将介绍一种在iOS开发中实现视频去水印的方法，并提供相应的代码示例。

AVFoundation框架

在iOS开发中，可以使用AVFoundation框架来处理音视频媒体。AVFoundation提供了一系列的类和方法，用于处理视频的录制、编辑、播放等操作。我们将使用AVFoundation来实现视频去水印功能。

获取视频

首先，我们需要获取待去水印的视频文件。可以通过UIImagePickerController类从相册或相机中选择视频。以下是一个示例代码，用于选择视频并将其保存到本地文件中。

import UIKit
import MobileCoreServices

class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    
    // 选择视频按钮点击事件
    @IBAction func selectVideoButtonTapped(_ sender: UIButton) {
        let imagePicker = UIImagePickerController()
        imagePicker.delegate = self
        imagePicker.sourceType = .photoLibrary
        imagePicker.mediaTypes = [kUTTypeMovie as String]
        present(imagePicker, animated: true, completion: nil)
    }
    
    // UIImagePickerControllerDelegate方法，选择视频完成后调用
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        if let url = info[.mediaURL] as? URL {
            saveVideoToDocuments(videoURL: url)
        }
        
        picker.dismiss(animated: true, completion: nil)
    }
    
    // 将选中的视频保存到本地文件中
    func saveVideoToDocuments(videoURL: URL) {
        guard let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else {
            return
        }
        
        let fileName = "video.mp4"
        let destinationURL = documentsDirectory.appendingPathComponent(fileName)
        
        do {
            try FileManager.default.copyItem(at: videoURL, to: destinationURL)
            print("Video saved to: \(destinationURL.absoluteString)")
        } catch {
            print("Failed to save video: \(error.localizedDescription)")
        }
    }
}

上述代码中，首先实现了一个ViewController类，并继承了UIImagePickerControllerDelegate和UINavigationControllerDelegate协议。在selectVideoButtonTapped方法中，创建了一个UIImagePickerController实例，并设置其代理为当前ViewController，然后打开相册，限制用户只能选择视频。在imagePickerController(_:didFinishPickingMediaWithInfo:)方法中，获取用户选择的视频URL，并调用saveVideoToDocuments方法将视频保存到本地文件中。

去除水印

接下来，我们需要使用AVFoundation框架来去除视频中的水印。以下是一个示例代码，用于去除视频中的水印。

import AVFoundation

func removeWatermarkFromVideo(videoURL: URL, completion: @escaping (URL?) -> Void) {
    let asset = AVURLAsset(url: videoURL)
    
    guard let exportSession = AVAssetExportSession(asset: asset, presetName: AVAssetExportPresetPassthrough) else {
        completion(nil)
        return
    }
    
    let fileName = "video_no_watermark.mp4"
    guard let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else {
        completion(nil)
        return
    }
    let destinationURL = documentsDirectory.appendingPathComponent(fileName)
    
    exportSession.outputURL = destinationURL
    exportSession.outputFileType = .mp4
    
    let videoComposition = AVMutableVideoComposition()
    videoComposition.frameDuration = CMTimeMake(value: 1, timescale: 30)
    videoComposition.renderSize = CGSize(width: 640, height: 480)
    
    let instruction = AVMutableVideoCompositionInstruction()
    instruction.timeRange = CMTimeRangeMake(start: .zero, duration: asset.duration)
    
    let videoTrack = asset.tracks(withMediaType: .video).first
    let layerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: videoTrack!)
    
    instruction.layerInstructions = [layerInstruction]
    videoComposition.instructions = [instruction]
    
    exportSession.videoComposition = videoComposition
    
    exportSession.exportAsynchronously {
        switch exportSession.status {
        case .completed:
            completion(exportSession.outputURL)
        case .failed, .cancelled:
            completion(nil)
        default:
            break
        }
    }
}

上述代码中，我们首先创建了一个AVURLAsset对象，用于表示待处理的视频。然后，我们创建了一个AVAssetExportSession