diff --git a/SilicaViewer/AppDelegate.swift b/SilicaViewer/AppDelegate.swift
index 65d742c..3f83f15 100644
--- a/SilicaViewer/AppDelegate.swift
+++ b/SilicaViewer/AppDelegate.swift
@@ -60,7 +60,11 @@ class AppDelegate: NSObject, NSApplicationDelegate, NSUserInterfaceValidations {
     }
     
     @IBAction func exportTimelapseAction(_ sender: Any) {
-        let document = NSApplication.shared.keyWindow?.windowController?.document as? Document;
+        guard let originalWindow = NSApplication.shared.keyWindow else {
+            return
+        }
+        
+        let document = originalWindow.windowController?.document as? Document;
 
         let savePanel = NSSavePanel()
         savePanel.title = "Save Timelapse"
@@ -74,10 +78,8 @@ class AppDelegate: NSObject, NSApplicationDelegate, NSUserInterfaceValidations {
                 let directory = NSTemporaryDirectory()
                 
                 let mixComposition = AVMutableComposition()
-                
-                var duration = CMTime.zero
-                
                 var instructions: [AVMutableVideoCompositionLayerInstruction] = []
+                var duration = CMTime.zero
                 
                 for entry in archive.makeIterator() {
                     if entry.path.contains(VideoPath) {
@@ -90,60 +92,52 @@ class AppDelegate: NSObject, NSApplicationDelegate, NSUserInterfaceValidations {
                         
                         let asset = AVAsset(url: fullURL)
                         
-                        guard
-                          let firstTrack = mixComposition.addMutableTrack(
-                            withMediaType: .video,
-                            preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
-                          else { return }
-                            
-                        // 3
-                        do {
-                          try firstTrack.insertTimeRange(
-                            CMTimeRangeMake(start: .zero, duration: asset.duration),
-                            of: asset.tracks(withMediaType: .video)[0],
-                            at: duration)
-                        } catch {
-                          print("Failed to load first track")
-                          return
+                        guard let track = mixComposition.addMutableTrack(withMediaType: .video, preferredTrackID: Int32(kCMPersistentTrackID_Invalid)) else {
+                            return
                         }
+                            
+                        try? track.insertTimeRange(CMTimeRangeMake(start: .zero, duration: asset.duration),
+                                                        of: asset.tracks(withMediaType: .video)[0],
+                                                        at: duration)
                         
                         duration = CMTimeAdd(duration, asset.duration)
                         
-                        let firstInstruction = AVMutableVideoCompositionLayerInstruction(
-                          assetTrack: firstTrack)
-                        firstInstruction.setOpacity(0.0, at: duration + asset.duration)
+                        let opacityInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: track)
+                        opacityInstruction.setOpacity(0.0, at: duration + asset.duration)
                         
-                        instructions.append(firstInstruction)
+                        instructions.append(opacityInstruction)
                     }
                 }
                 
                 let mainInstruction = AVMutableVideoCompositionInstruction()
-                mainInstruction.timeRange = CMTimeRangeMake(
-                  start: .zero,
-                  duration: duration)
+                mainInstruction.timeRange = CMTimeRangeMake(start: .zero, duration: duration)
                 mainInstruction.layerInstructions = instructions
                 
                 let mainComposition = AVMutableVideoComposition()
                 mainComposition.instructions = [mainInstruction]
                 mainComposition.frameDuration = CMTimeMake(value: 1, timescale: 30)
-                mainComposition.renderSize = CGSize(
-                    width: document!.info.videoFrameWidth,
-                    height: document!.info.videoFrameHeight)
+                mainComposition.renderSize = CGSize(width: document!.info.videoFrame.0, height: document!.info.videoFrame.1)
                 
-                self.exporter = AVAssetExportSession(
-                  asset: mixComposition,
-                  presetName: AVAssetExportPresetHighestQuality)
-                  
+                self.exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)
                 self.exporter?.outputURL = savePanel.url!
                 self.exporter?.outputFileType = AVFileType.mp4
-                self.exporter?.shouldOptimizeForNetworkUse = true
                 self.exporter?.videoComposition = mainComposition
                 
-                self.exporter?.exportAsynchronously {
-                    
-                    dump(self.exporter?.error?.localizedDescription);
+                let alert = NSAlert()
+                alert.messageText = "Exporting timelapse..."
+                alert.addButton(withTitle: "Cancel")
+                alert.beginSheetModal(for: originalWindow) { (resonse) in
+                    self.exporter?.cancelExport()
+                    alert.window.close()
+                }
+                
+                self.exporter?.exportAsynchronously {
+                    if self.exporter?.status != .cancelled {
+                        DispatchQueue.main.sync {
+                            alert.window.close()
+                        }
+                    }
                 }
-
             }
         }
     }
diff --git a/SilicaViewer/Document.swift b/SilicaViewer/Document.swift
index a2d2c04..6bb4778 100644
--- a/SilicaViewer/Document.swift
+++ b/SilicaViewer/Document.swift
@@ -42,8 +42,7 @@ struct SilicaDocument {
     
     var layers: [SilicaLayer] = []
     
-    var videoFrameWidth: Int = 0
-    var videoFrameHeight: Int = 0
+    var videoFrame: (Int, Int) = (0, 0)
     
     lazy var nsSize = {
         return NSSize(width: width, height: height)
@@ -375,19 +374,8 @@ class Document: NSDocument {
             let frameSizeClassKey = videoResolution["frameSize"]
             let frameSizeClassID = getClassID(id: frameSizeClassKey)
             let frameSize = objectsArray[frameSizeClassID] as! String
-            
-            // frameSize
-                        //SilicaDocumentVideoSegmentInfoKey
-            // videoQualityKey
-            
-            dump(frameSize, indent: 5)
-            
-            guard let (frameWidth, frameHeight) = parsePairString(frameSize) else {
-                return
-            }
-            
-            info.videoFrameWidth = frameWidth
-            info.videoFrameHeight = frameHeight
+                        
+            info.videoFrame = parsePairString(frameSize)!
                         
             let colorProfileClassKey = dict["colorProfile"]
             let colorProfileClassID = getClassID(id: colorProfileClassKey)
@@ -437,12 +425,9 @@ class Document: NSDocument {
             let sizeClassID = getClassID(id: sizeClassKey)
             let sizeString = objectsArray[sizeClassID] as! String
     
-            let sizeComponents = sizeString.replacingOccurrences(of: "{", with: "").replacingOccurrences(of: "}", with: "").components(separatedBy: ", ")
-            let width = Int(sizeComponents[0])
-            let height = Int(sizeComponents[1])
-            
-            info.width = width!
-            info.height = height!
+            let (width, height) = parsePairString(sizeString)!
+            info.width = width
+            info.height = height
             
             columns = Int(ceil(Float(info.width) / Float(info.tileSize)))
             rows = Int(ceil(Float(info.height) / Float(info.tileSize))) + 1 // TODO: lol why