This code writes series of pixel buffer to files

WritePixelBufferToFiles.swift

        //generate a file url to store the video. some_image.jpg becomes some_image.mov
        guard let outputMovieURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first?.appendingPathComponent("output.mov") else {
            fatalError("somehting went wrong") //an error i made up
        }
        //delete any old file
        do {
            try FileManager.default.removeItem(at: outputMovieURL)
        } catch {
            print("Could not remove file \(error.localizedDescription)")
        }
        //create an assetwriter instance
        guard let assetwriter = try? AVAssetWriter(outputURL: outputMovieURL, fileType: .mov) else {
            abort()
        }
        //generate 1080p settings
        let settingsAssistant = AVOutputSettingsAssistant(preset: .preset1920x1080)?.videoSettings
        //create a single video input
        let assetWriterInput = AVAssetWriterInput(mediaType: .video, outputSettings: settingsAssistant)
        //create an adaptor for the pixel buffer
        let assetWriterAdaptor = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: assetWriterInput, sourcePixelBufferAttributes: nil)
        //add the input to the asset writer
        assetwriter.add(assetWriterInput)
        //begin the session
        assetwriter.startWriting()
        assetwriter.startSession(atSourceTime: CMTime.zero)
        //determine how many frames we need to generate
        let framesPerSecond = 30
        //duration is the number of seconds for the final video
        let totalFrames = 1 * framesPerSecond
        var frameCount = 0

//replace the while true condition to loop through the pixelbuffers
      while true{
        if assetWriterInput.isReadyForMoreMediaData {
                    let frameTime = CMTimeMake(value: Int64(frameCount), timescale: Int32(framesPerSecond))
                    //append the contents of the pixelBuffer at the correct time
                    assetWriterAdaptor.append(pixelBuffer, withPresentationTime: frameTime)
                    frameCount+=1
                    print(frameCount)
                }
            }
        //close everything
        assetWriterInput.markAsFinished()
        assetwriter.finishWriting {
            print("writing complete ✅")
            //              pixelBuffer = nil
            //outputMovieURL now has the video
        }