视频中的图像/文本叠加 [英] Image/Text overlay in video swift

问题描述

我正在使用swift使用图像叠加来实现视频中的水印效果.为此我正在使用AVFoundation，但是以某种方式我没有成功.

I am work with image overlay for watermark effect in video using swift.I am using AVFoundation for this but somehow I am not succeed.

以下是我的叠加图像/文字代码

Following is my code for overlay image/text

    let path = NSBundle.mainBundle().pathForResource("sample_movie", ofType:"mp4")
    let fileURL = NSURL(fileURLWithPath: path!)

    let composition = AVMutableComposition()
    var vidAsset = AVURLAsset(URL: fileURL, options: nil)

    // get video track
    let vtrack =  vidAsset.tracksWithMediaType(AVMediaTypeVideo)
    let videoTrack:AVAssetTrack = vtrack[0] as! AVAssetTrack
    let vid_duration = videoTrack.timeRange.duration
    let vid_timerange = CMTimeRangeMake(kCMTimeZero, vidAsset.duration)

    var error: NSError?
    let compositionvideoTrack:AVMutableCompositionTrack = composition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID())
    compositionvideoTrack.insertTimeRange(vid_timerange, ofTrack: videoTrack, atTime: kCMTimeZero, error: &error)

    compositionvideoTrack.preferredTransform = videoTrack.preferredTransform

    // Watermark Effect
    let size = videoTrack.naturalSize

    let imglogo = UIImage(named: "image.png")
    let imglayer = CALayer()
    imglayer.contents = imglogo?.CGImage
    imglayer.frame = CGRectMake(5, 5, 100, 100)
    imglayer.opacity = 0.6

    // create text Layer
    let titleLayer = CATextLayer()
    titleLayer.backgroundColor = UIColor.whiteColor().CGColor
    titleLayer.string = "Dummy text"
    titleLayer.font = UIFont(name: "Helvetica", size: 28)
    titleLayer.shadowOpacity = 0.5
    titleLayer.alignmentMode = kCAAlignmentCenter
    titleLayer.frame = CGRectMake(0, 50, size.width, size.height / 6)

    let videolayer = CALayer()
    videolayer.frame = CGRectMake(0, 0, size.width, size.height)

    let parentlayer = CALayer()
    parentlayer.frame = CGRectMake(0, 0, size.width, size.height)
    parentlayer.addSublayer(videolayer)
    parentlayer.addSublayer(imglayer)
    parentlayer.addSublayer(titleLayer)

    let layercomposition = AVMutableVideoComposition()
    layercomposition.frameDuration = CMTimeMake(1, 30)
    layercomposition.renderSize = size
    layercomposition.animationTool = AVVideoCompositionCoreAnimationTool(postProcessingAsVideoLayer: videolayer, inLayer: parentlayer)

    // instruction for watermark
    let instruction = AVMutableVideoCompositionInstruction()
    instruction.timeRange = CMTimeRangeMake(kCMTimeZero, composition.duration)
    let videotrack = composition.tracksWithMediaType(AVMediaTypeVideo)[0] as! AVAssetTrack
    let layerinstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: videotrack)
    instruction.layerInstructions = NSArray(object: layerinstruction) as [AnyObject]
    layercomposition.instructions = NSArray(object: instruction) as [AnyObject]

    //  create new file to receive data
    let dirPaths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let docsDir: AnyObject = dirPaths[0]
    let movieFilePath = docsDir.stringByAppendingPathComponent("result.mov")
    let movieDestinationUrl = NSURL(fileURLWithPath: movieFilePath)       

    // use AVAssetExportSession to export video
    let assetExport = AVAssetExportSession(asset: composition, presetName:AVAssetExportPresetHighestQuality)
    assetExport.outputFileType = AVFileTypeQuickTimeMovie 
    assetExport.outputURL = movieDestinationUrl
    assetExport.exportAsynchronouslyWithCompletionHandler({
        switch assetExport.status{
        case  AVAssetExportSessionStatus.Failed:
            println("failed \(assetExport.error)")
        case AVAssetExportSessionStatus.Cancelled:
            println("cancelled \(assetExport.error)")
        default:
            println("Movie complete")


            // play video
            NSOperationQueue.mainQueue().addOperationWithBlock({ () -> Void in
                self.playVideo(movieDestinationUrl!)
            })
        }
    })    

通过此代码，我无法实现叠加....我不知道自己在做什么错事...

By this code, I am not achieve overlay....I don't know what I am doing wrong...

问题:

• 此代码中是否缺少任何内容?还是这个代码有问题?
• 此代码仅适用于录制的视频还是包括图库中的视频在内的所有视频?

推荐答案

@El Captain提供的代码可以使用.它只是缺少了:

The code provided by @El Captain would work. It's only missing:

    assetExport.videoComposition = layercomposition

您可以在实例化 AVAssetExportSession

注意::最初提供的代码只会导出视频轨道，而不会导出音频轨道.如果您需要音轨，则可以在配置 compositionvideoTrack 后添加类似以下内容:

NOTE: The code originally provided would only export the video track but not the audio track. If you need the audio track you could add something like this after you configure the compositionvideoTrack:

let compositionAudioTrack:AVMutableCompositionTrack = composition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID())
    for audioTrack in audioTracks {
        try! compositionAudioTrack.insertTimeRange(audioTrack.timeRange, ofTrack: audioTrack, atTime: kCMTimeZero)
    }

这篇关于视频中的图像/文本叠加的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！