If rendering crashes while initializing, an Error Screen telling the user to install ffmpeg is displayed | https://trello.com/c/EDDIqP0V/

src/main/java/eu/crushedpixel/replaymod/replay/ReplayProcess.java

@@ -14,6 +14,8 @@ import eu.crushedpixel.replaymod.timer.EnchantmentTimer;
 import eu.crushedpixel.replaymod.timer.ReplayTimer;
 import eu.crushedpixel.replaymod.video.VideoRenderer;
 import net.minecraft.client.Minecraft;
+import net.minecraft.client.gui.GuiErrorScreen;
+import net.minecraft.client.resources.I18n;
 
 import java.io.IOException;
 
@@ -98,13 +100,20 @@ public class ReplayProcess {
             ReplayMod.chatMessageHandler.addLocalizedChatMessage("replaymod.chat.pathstarted", ChatMessageType.INFORMATION);
             mc.timer.timerSpeed = 1;
         } else {
+            boolean success = false;
             try {
                 isVideoRecording = true;
-                boolean success = new VideoRenderer(renderOptions).renderVideo();
-                isVideoRecording = false;
-                stopReplayProcess(success);
+                VideoRenderer videoRenderer = new VideoRenderer(renderOptions);
+                success = videoRenderer.renderVideo();
             } catch (IOException e) {
                 e.printStackTrace();
+
+                GuiErrorScreen errorScreen = new GuiErrorScreen(I18n.format("replaymod.gui.rendering.error.title"),
+                        I18n.format("replaymod.gui.rendering.error.message"));
+                mc.displayGuiScreen(errorScreen);
+            } finally {
+                isVideoRecording = false;
+                stopReplayProcess(success);
             }
         }
     }

src/main/resources/assets/replaymod/lang/en_US.lang

@@ -303,6 +303,10 @@ replaymod.gui.rendering.progress=Frames rendered: %1$d / %2$d
 replaymod.gui.rendering.timetaken=Render Time
 replaymod.gui.rendering.timeleft=Time Left
 
+#Render Errors
+replaymod.gui.rendering.error.title=Rendering Failed
+replaymod.gui.rendering.error.message=To render a video, you need to have ffmpeg installed. http://ffmpeg.org
+
 #Ingame Menu
 replaymod.gui.ingame.menu.addposkeyframe=Add Position Keyframe
 replaymod.gui.ingame.menu.removeposkeyframe=Remove Position Keyframe