How do I export UIImage array as a movie?

Question

I have a serious problem: I have an NSArray with several UIImage objects. What I now want to do, is create movie from those UIImages.

Answer 1

Here's the swift3 version how to convert Images array to the Video

import Foundation
import AVFoundation
import UIKit

typealias CXEMovieMakerCompletion = (URL) -> Void
typealias CXEMovieMakerUIImageExtractor = (AnyObject) -> UIImage?


public class ImagesToVideoUtils: NSObject {

    static let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
    static let tempPath = paths[0] + "/exprotvideo.mp4"
    static let fileURL = URL(fileURLWithPath: tempPath)
//    static let tempPath = NSTemporaryDirectory() + "/exprotvideo.mp4"
//    static let fileURL = URL(fileURLWithPath: tempPath)


    var assetWriter:AVAssetWriter!
    var writeInput:AVAssetWriterInput!
    var bufferAdapter:AVAssetWriterInputPixelBufferAdaptor!
    var videoSettings:[String : Any]!
    var frameTime:CMTime!
    //var fileURL:URL!

    var completionBlock: CXEMovieMakerCompletion?
    var movieMakerUIImageExtractor:CXEMovieMakerUIImageExtractor?


    public class func videoSettings(codec:String, width:Int, height:Int) -> [String: Any]{
        if(Int(width) % 16 != 0){
            print("warning: video settings width must be divisible by 16")
        }

        let videoSettings:[String: Any] = [AVVideoCodecKey: AVVideoCodecJPEG, //AVVideoCodecH264,
                                           AVVideoWidthKey: width,
                                           AVVideoHeightKey: height]

        return videoSettings
    }

    public init(videoSettings: [String: Any]) {
        super.init()


        if(FileManager.default.fileExists(atPath: ImagesToVideoUtils.tempPath)){
            guard (try? FileManager.default.removeItem(atPath: ImagesToVideoUtils.tempPath)) != nil else {
                print("remove path failed")
                return
            }
        }


        self.assetWriter = try! AVAssetWriter(url: ImagesToVideoUtils.fileURL, fileType: AVFileTypeQuickTimeMovie)

        self.videoSettings = videoSettings
        self.writeInput = AVAssetWriterInput(mediaType: AVMediaTypeVideo, outputSettings: videoSettings)
        assert(self.assetWriter.canAdd(self.writeInput), "add failed")

        self.assetWriter.add(self.writeInput)
        let bufferAttributes:[String: Any] = [kCVPixelBufferPixelFormatTypeKey as String: Int(kCVPixelFormatType_32ARGB)]
        self.bufferAdapter = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: self.writeInput, sourcePixelBufferAttributes: bufferAttributes)
        self.frameTime = CMTimeMake(1, 5)
    }

    func createMovieFrom(urls: [URL], withCompletion: @escaping CXEMovieMakerCompletion){
        self.createMovieFromSource(images: urls as [AnyObject], extractor:{(inputObject:AnyObject) ->UIImage? in
            return UIImage(data: try! Data(contentsOf: inputObject as! URL))}, withCompletion: withCompletion)
    }

    func createMovieFrom(images: [UIImage], withCompletion: @escaping CXEMovieMakerCompletion){
        self.createMovieFromSource(images: images, extractor: {(inputObject:AnyObject) -> UIImage? in
            return inputObject as? UIImage}, withCompletion: withCompletion)
    }

    func createMovieFromSource(images: [AnyObject], extractor: @escaping CXEMovieMakerUIImageExtractor, withCompletion: @escaping CXEMovieMakerCompletion){
        self.completionBlock = withCompletion

        self.assetWriter.startWriting()
        self.assetWriter.startSession(atSourceTime: kCMTimeZero)

        let mediaInputQueue = DispatchQueue(label: "mediaInputQueue")
        var i = 0
        let frameNumber = images.count

        self.writeInput.requestMediaDataWhenReady(on: mediaInputQueue){
            while(true){
                if(i >= frameNumber){
                    break
                }

                if (self.writeInput.isReadyForMoreMediaData){
                    var sampleBuffer:CVPixelBuffer?
                    autoreleasepool{
                        let img = extractor(images[i])
                        if img == nil{
                            i += 1
                            print("Warning: counld not extract one of the frames")
                            //continue
                        }
                        sampleBuffer = self.newPixelBufferFrom(cgImage: img!.cgImage!)
                    }
                    if (sampleBuffer != nil){
                        if(i == 0){
                            self.bufferAdapter.append(sampleBuffer!, withPresentationTime: kCMTimeZero)
                        }else{
                            let value = i - 1
                            let lastTime = CMTimeMake(Int64(value), self.frameTime.timescale)
                            let presentTime = CMTimeAdd(lastTime, self.frameTime)
                            self.bufferAdapter.append(sampleBuffer!, withPresentationTime: presentTime)
                        }
                        i = i + 1
                    }
                }
            }
            self.writeInput.markAsFinished()
            self.assetWriter.finishWriting {
                DispatchQueue.main.sync {
                    self.completionBlock!(ImagesToVideoUtils.fileURL)
                }
            }
        }
    }

    func newPixelBufferFrom(cgImage:CGImage) -> CVPixelBuffer?{
        let options:[String: Any] = [kCVPixelBufferCGImageCompatibilityKey as String: true, kCVPixelBufferCGBitmapContextCompatibilityKey as String: true]
        var pxbuffer:CVPixelBuffer?
        let frameWidth = self.videoSettings[AVVideoWidthKey] as! Int
        let frameHeight = self.videoSettings[AVVideoHeightKey] as! Int

        let status = CVPixelBufferCreate(kCFAllocatorDefault, frameWidth, frameHeight, kCVPixelFormatType_32ARGB, options as CFDictionary?, &pxbuffer)
        assert(status == kCVReturnSuccess && pxbuffer != nil, "newPixelBuffer failed")

        CVPixelBufferLockBaseAddress(pxbuffer!, CVPixelBufferLockFlags(rawValue: 0))
        let pxdata = CVPixelBufferGetBaseAddress(pxbuffer!)
        let rgbColorSpace = CGColorSpaceCreateDeviceRGB()
        let context = CGContext(data: pxdata, width: frameWidth, height: frameHeight, bitsPerComponent: 8, bytesPerRow: CVPixelBufferGetBytesPerRow(pxbuffer!), space: rgbColorSpace, bitmapInfo: CGImageAlphaInfo.noneSkipFirst.rawValue)
        assert(context != nil, "context is nil")

        context!.concatenate(CGAffineTransform.identity)
        context!.draw(cgImage, in: CGRect(x: 0, y: 0, width: cgImage.width, height: cgImage.height))
        CVPixelBufferUnlockBaseAddress(pxbuffer!, CVPixelBufferLockFlags(rawValue: 0))
        return pxbuffer
    }
}

I use it together with screen capturing, to basically create a video of screen capturing, here's the full story/complete example.