Add a text overlay with AVMutableVideoComposition to a specific timerange

Question

I have found a few examples that show how to add a text overlay on a video.

Ray\'s Tutorial - http://www.raywenderlich.com/30200/avfoundation-tutorial-adding-overlay

Answer 1

We should add two opacity animations for Video overlay at particular time rang. First animation for show overlay at start duration and second animation for hide overlay at end duration. We should take care to set fill mode of animation.

Sample code of Video overlay for particular time Rang.

            let textLayer = CATextLayer()
            textLayer.opacity = 0.0
            .
            .
            textLayer.frame = CGRect(x: 0.0, y: 0.0, width: 150.0, height:100.0)
            textLayer.string = "Overlay Text"

            let startVisible = CABasicAnimation.init(keyPath:"opacity")
            startVisible.duration = 0.1    // for fade in duration
            startVisible.repeatCount = 1
            startVisible.fromValue = 0.0  
            startVisible.toValue = 1.0
            startVisible.beginTime = overlay.startTime.seconds // overlay time range start duration
            startVisible.isRemovedOnCompletion = false 
            startVisible.fillMode = kCAFillModeForwards 
            textLayer.add(startVisible, forKey: "startAnimation")

            let endVisible = CABasicAnimation.init(keyPath:"opacity")
            endVisible.duration = 0.1
            endVisible.repeatCount = 1
            endVisible.fromValue = 1.0
            endVisible.toValue = 0.0
            endVisible.beginTime = overlay.endTime.seconds
            endVisible.fillMode = kCAFillModeForwards
            endVisible.isRemovedOnCompletion = false
            textLayer.add(endVisible, forKey: "endAnimation")