ios - 如何在 iOS 上捕获的视频中添加水印 - Swift 编程

Question

有人可以帮助我使用 Swift 编程语言为录制的视频添加水印吗？作为引用，我正在研究 AVFoundation 框架。

下面是两个要求，

1. 使用 UILabel 作为文本的水印
2. 使用 UIImage 的水印

提前致谢。

Answer 1

我已经找到解决方案并更新@m177312 给出的答案检查link

import UIKit
import AssetsLibrary
import AVFoundation

enum QUWatermarkPosition {
    case TopLeft
    case TopRight
    case BottomLeft
    case BottomRight
    case Default
}

class QUWatermarkManager: NSObject {

    func watermark(video videoAsset:AVAsset, watermarkText text : String, saveToLibrary flag : Bool, watermarkPosition position : QUWatermarkPosition, completion : ((status : AVAssetExportSessionStatus!, session: AVAssetExportSession!, outputURL : NSURL!) -> ())?) {
        self.watermark(video: videoAsset, watermarkText: text, imageName: nil, saveToLibrary: flag, watermarkPosition: position) { (status, session, outputURL) -> () in
            completion!(status: status, session: session, outputURL: outputURL)
        }
    }

    func watermark(video videoAsset:AVAsset, imageName name : String, saveToLibrary flag : Bool, watermarkPosition position : QUWatermarkPosition, completion : ((status : AVAssetExportSessionStatus!, session: AVAssetExportSession!, outputURL : NSURL!) -> ())?) {
        self.watermark(video: videoAsset, watermarkText: nil, imageName: name, saveToLibrary: flag, watermarkPosition: position) { (status, session, outputURL) -> () in
            completion!(status: status, session: session, outputURL: outputURL)
        }
    }

    private func watermark(video videoAsset:AVAsset, watermarkText text : String!, imageName name : String!, saveToLibrary flag : Bool, watermarkPosition position : QUWatermarkPosition, completion : ((status : AVAssetExportSessionStatus!, session: AVAssetExportSession!, outputURL : NSURL!) -> ())?) {

        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), { () -> Void in
            // 1 - Create AVMutableComposition object. This object will hold your AVMutableCompositionTrack instances.
            var mixComposition = AVMutableComposition()

            // 2 - Create video tracks
            var compositionVideoTrack = mixComposition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
            var clipVideoTrack = videoAsset.tracksWithMediaType(AVMediaTypeVideo)[0] as! AVAssetTrack
            compositionVideoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration), ofTrack: clipVideoTrack, atTime: kCMTimeZero, error: nil)
            clipVideoTrack.preferredTransform

            // Video size
            let videoSize = clipVideoTrack.naturalSize

            // sorts the layer in proper order and add title layer
            var parentLayer = CALayer()
            var videoLayer = CALayer()
            parentLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height)
            videoLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height)
            parentLayer.addSublayer(videoLayer)

            if text != nil {
                // Adding watermark text
                var titleLayer = CATextLayer()
                titleLayer.backgroundColor = UIColor.redColor().CGColor
                titleLayer.string = text
                titleLayer.font = "Helvetica"
                titleLayer.fontSize = 15
                titleLayer.alignmentMode = kCAAlignmentCenter
                titleLayer.bounds = CGRectMake(0, 0, videoSize.width, videoSize.height)
                parentLayer.addSublayer(titleLayer)

                println("\(videoSize.width)")
                println("\(videoSize.height)")
            } else if name != nil {
                // Adding image 
                var watermarkImage = UIImage(named: name)
                var imageLayer = CALayer()
                imageLayer.contents = watermarkImage?.CGImage

                var xPosition : CGFloat = 0.0
                var yPosition : CGFloat = 0.0
                let imageSize : CGFloat = 57.0

                switch (position) {
                case .TopLeft:
                    xPosition = 0
                    yPosition = 0
                    break
                case .TopRight:
                    xPosition = videoSize.width - imageSize
                    yPosition = 0
                    break
                case .BottomLeft:
                    xPosition = 0
                    yPosition = videoSize.height - imageSize
                    break
                case .BottomRight, .Default:
                    xPosition = videoSize.width - imageSize
                    yPosition = videoSize.height - imageSize
                    break
                default:
                    break
                }

                println("\(xPosition)")
                println("\(yPosition)")

                imageLayer.frame = CGRectMake(xPosition, yPosition, imageSize, imageSize)
                imageLayer.opacity = 0.65
                parentLayer.addSublayer(imageLayer)
            }

            var videoComp = AVMutableVideoComposition()
            videoComp.renderSize = videoSize
            videoComp.frameDuration = CMTimeMake(1, 30)
            videoComp.animationTool = AVVideoCompositionCoreAnimationTool(postProcessingAsVideoLayer: videoLayer, inLayer: parentLayer)

            /// instruction
            var instruction = AVMutableVideoCompositionInstruction()
            instruction.timeRange = CMTimeRangeMake(kCMTimeZero, mixComposition.duration)
            var videoTrack = mixComposition.tracksWithMediaType(AVMediaTypeVideo)[0] as! AVAssetTrack

            let layerInstruction = self.videoCompositionInstructionForTrack(compositionVideoTrack, asset: videoAsset)

            //var layerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: videoTrack)

            instruction.layerInstructions = [layerInstruction]
            videoComp.instructions = [instruction]

            // 4 - Get path
            let documentDirectory = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as! String
            var dateFormatter = NSDateFormatter()
            dateFormatter.dateStyle = .LongStyle
            dateFormatter.timeStyle = .ShortStyle
            let date = dateFormatter.stringFromDate(NSDate())
            let savePath = documentDirectory.stringByAppendingPathComponent("watermarkVideo-\(date).mov")
            let url = NSURL(fileURLWithPath: savePath)

            // 5 - Create Exporter
            let exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)
            exporter.outputURL = url
            exporter.outputFileType = AVFileTypeQuickTimeMovie
            exporter.shouldOptimizeForNetworkUse = true
            exporter.videoComposition = videoComp

            // 6 - Perform the Export
            exporter.exportAsynchronouslyWithCompletionHandler() {
                dispatch_async(dispatch_get_main_queue(), { () -> Void in
                    if exporter.status == AVAssetExportSessionStatus.Completed {
                        let outputURL = exporter.outputURL
                        if flag {
                            // Save to library
                            let library = ALAssetsLibrary()
                            if library.videoAtPathIsCompatibleWithSavedPhotosAlbum(outputURL) {
                                library.writeVideoAtPathToSavedPhotosAlbum(outputURL,
                                    completionBlock: { (assetURL:NSURL!, error:NSError!) -> Void in
                                        completion!(status: AVAssetExportSessionStatus.Completed, session: exporter, outputURL: outputURL)
                                })
                            }
                        } else {
                            // Dont svae to library
                            completion!(status: AVAssetExportSessionStatus.Completed, session: exporter, outputURL: outputURL)
                        }

                    } else {
                        // Error
                        completion!(status: exporter.status, session: exporter, outputURL: nil)
                    }
                })
            }
        })
    }


    private func orientationFromTransform(transform: CGAffineTransform) -> (orientation: UIImageOrientation, isPortrait: Bool) {
        var assetOrientation = UIImageOrientation.Up
        var isPortrait = false
        if transform.a == 0 && transform.b == 1.0 && transform.c == -1.0 && transform.d == 0 {
            assetOrientation = .Right
            isPortrait = true
        } else if transform.a == 0 && transform.b == -1.0 && transform.c == 1.0 && transform.d == 0 {
            assetOrientation = .Left
            isPortrait = true
        } else if transform.a == 1.0 && transform.b == 0 && transform.c == 0 && transform.d == 1.0 {
            assetOrientation = .Up
        } else if transform.a == -1.0 && transform.b == 0 && transform.c == 0 && transform.d == -1.0 {
            assetOrientation = .Down
        }
        return (assetOrientation, isPortrait)
    }

    private func videoCompositionInstructionForTrack(track: AVCompositionTrack, asset: AVAsset) -> AVMutableVideoCompositionLayerInstruction {
        let instruction = AVMutableVideoCompositionLayerInstruction(assetTrack: track)
        let assetTrack = asset.tracksWithMediaType(AVMediaTypeVideo)[0] as! AVAssetTrack

        var transform = assetTrack.preferredTransform
        let assetInfo = orientationFromTransform(transform)

        var scaleToFitRatio = UIScreen.mainScreen().bounds.width / assetTrack.naturalSize.width
        if assetInfo.isPortrait {
            scaleToFitRatio = UIScreen.mainScreen().bounds.width / assetTrack.naturalSize.height
            let scaleFactor = CGAffineTransformMakeScale(scaleToFitRatio, scaleToFitRatio)
            instruction.setTransform(CGAffineTransformConcat(assetTrack.preferredTransform, scaleFactor),
                atTime: kCMTimeZero)
        } else {
            let scaleFactor = CGAffineTransformMakeScale(scaleToFitRatio, scaleToFitRatio)
            var concat = CGAffineTransformConcat(CGAffineTransformConcat(assetTrack.preferredTransform, scaleFactor), CGAffineTransformMakeTranslation(0, UIScreen.mainScreen().bounds.width / 2))
            if assetInfo.orientation == .Down {
                let fixUpsideDown = CGAffineTransformMakeRotation(CGFloat(M_PI))
                let windowBounds = UIScreen.mainScreen().bounds
                let yFix = assetTrack.naturalSize.height + windowBounds.height
                let centerFix = CGAffineTransformMakeTranslation(assetTrack.naturalSize.width, yFix)
                concat = CGAffineTransformConcat(CGAffineTransformConcat(fixUpsideDown, centerFix), scaleFactor)
            }
            instruction.setTransform(concat, atTime: kCMTimeZero)
        }

        return instruction
    }
}

感谢许多在 StackOverflow 上帮助过我的人。如果我没有标记答案在这里的任何人，我已经从堆栈溢出中获取了很多引用资料，我向他们道歉。谢谢你帮助我。希望这个回答对大家有所帮助。