Image/Text overlay in video swift

Question

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.

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!)
            })
        }
    })    

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

Questions:

• Is there any missing thing in this code? Or any problem with this code?
• Is this code only worked with recorded video or all videos including videos from gallery?

Answer 1

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

    assetExport.videoComposition = layercomposition

You can add this right after the instantiation of the AVAssetExportSession

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)
    }