Upgrade Swift language version to 4.2

Package.swift

@@ -56,5 +56,5 @@ let package = Package(
     products: platformProducts,
     dependencies: platformDependencies,
     targets: platformTargets,
-    swiftLanguageVersions: [.v4]
+    swiftLanguageVersions: [.v4_2]
 )

README.md

@@ -24,8 +24,8 @@ Currently, GPUImage uses Lode Vandevenne's <a href="https://lodev.org/lodepng/">
 
 ## Technical requirements ##
 
-- Swift 3
-- Xcode 8.0 on Mac or iOS
+- Swift 4.2 or higher
+- Xcode 10.1 or higher on Mac or iOS
 - iOS: 8.0 or higher (Swift is supported on 7.0, but not Mac-style frameworks)
 - OSX: 10.9 or higher
 - Linux: Wherever Swift code can be compiled. Currently, that's Ubuntu 14.04 or higher, along with the many other places it has been ported to. I've gotten this running on the latest Raspbian, for example. For camera input, Video4Linux needs to be installed.

framework/Source/Apple/MovieInput.swift

@@ -10,7 +10,7 @@ public class MovieInput: ImageSource {
     let playAtActualSpeed:Bool
     let loop:Bool
     var videoEncodingIsFinished = false
-    var previousFrameTime = kCMTimeZero
+    var previousFrameTime = CMTime.zero
     var previousActualFrameTime = CFAbsoluteTimeGetCurrent()
 
     var numberOfFramesCaptured = 0
@@ -55,7 +55,7 @@ public class MovieInput: ImageSource {
                 var readerVideoTrackOutput:AVAssetReaderOutput? = nil;
 
                 for output in self.assetReader.outputs {
-                    if(output.mediaType == AVMediaType.video.rawValue) {
+                    if(output.mediaType == .video) {
                         readerVideoTrackOutput = output;
                     }
                 }

framework/Source/Apple/MovieOutput.swift

@@ -20,8 +20,8 @@ public class MovieOutput: ImageConsumer, AudioEncodingTarget {
     private var videoEncodingIsFinished = false
     private var audioEncodingIsFinished = false
     private var startTime:CMTime?
-    private var previousFrameTime = kCMTimeNegativeInfinity
-    private var previousAudioTime = kCMTimeNegativeInfinity
+    private var previousFrameTime = CMTime.negativeInfinity
+    private var previousAudioTime = CMTime.negativeInfinity
     private var encodingLiveVideo:Bool
     var pixelBuffer:CVPixelBuffer? = nil
     var renderFramebuffer:Framebuffer!
@@ -45,7 +45,7 @@ public class MovieOutput: ImageConsumer, AudioEncodingTarget {
         self.size = size
         assetWriter = try AVAssetWriter(url:URL, fileType:fileType)
         // Set this to make sure that a functional movie is produced, even if the recording is cut off mid-stream. Only the last second should be lost in that case.
-        assetWriter.movieFragmentInterval = CMTimeMakeWithSeconds(1.0, 1000)
+        assetWriter.movieFragmentInterval = CMTimeMakeWithSeconds(1.0, preferredTimescale: 1000)
 
         var localSettings:[String:AnyObject]
         if let settings = settings {
@@ -56,7 +56,7 @@ public class MovieOutput: ImageConsumer, AudioEncodingTarget {
 
         localSettings[AVVideoWidthKey] = localSettings[AVVideoWidthKey] ?? NSNumber(value:size.width)
         localSettings[AVVideoHeightKey] = localSettings[AVVideoHeightKey] ?? NSNumber(value:size.height)
-        localSettings[AVVideoCodecKey] =  localSettings[AVVideoCodecKey] ?? AVVideoCodecH264 as NSString
+        localSettings[AVVideoCodecKey] =  localSettings[AVVideoCodecKey] ?? AVVideoCodecType.h264 as NSString
 
         assetWriterVideoInput = AVAssetWriterInput(mediaType:AVMediaType.video, outputSettings:localSettings)
         assetWriterVideoInput.expectsMediaDataInRealTime = liveVideo
@@ -266,7 +266,7 @@ public extension Timestamp {
 
     var asCMTime:CMTime {
         get {
-            return CMTimeMakeWithEpoch(value, timescale, epoch)
+            return CMTimeMakeWithEpoch(value: value, timescale: timescale, epoch: epoch)
         }
     }
 }

framework/Source/Apple/PictureOutput.swift

@@ -97,8 +97,8 @@ public class PictureOutput: ImageConsumer {
 #if canImport(UIKit)
             let image = UIImage(cgImage:cgImageFromBytes, scale:1.0, orientation:.up)
             switch encodedImageFormat {
-                case .png: imageData = UIImagePNGRepresentation(image)! // TODO: Better error handling here
-                case .jpeg: imageData = UIImageJPEGRepresentation(image, 0.8)! // TODO: Be able to set image quality
+                case .png: imageData = image.pngData()! // TODO: Better error handling here
+                case .jpeg: imageData = image.jpegData(compressionQuality: 0.8)! // TODO: Be able to set image quality
             }
 #else
             let bitmapRepresentation = NSBitmapImageRep(cgImage:cgImageFromBytes)