Search for ffmpeg executable in common locations to simplify setup

docs/content.md

@@ -32,6 +32,10 @@ Next, download this **Batch Script** to quickly install FFmpeg: <https://replaym
 Put the downloaded script into the folder where you extracted FFmpeg and run itt by double-clicking it.
 If you see a success message in the console, you've sucessfully installed **FFmpeg**!
 
+Alternatively, starting with ReplayMod 2.0.0-b5, you can also extract the downloaded `.7z` file into a `ffmpeg` folder
+(you have to create it, it doesn't exist by default) in your `.minecraft` folder. No need to run any **Batch Script**.
+The FFmpeg executable should end up at `.minecraft/ffmpeg/bin/ffmpeg.exe`.
+
 ### Mac OSX [mac]
 On OSX, you can install **FFmpeg** with **[Homebrew](http://brew.sh/)** using `brew install ffmpeg`.
 

src/main/java/com/replaymod/render/VideoWriter.java

@@ -7,17 +7,27 @@ import com.replaymod.render.utils.StreamPipe;
 import net.minecraft.client.Minecraft;
 import net.minecraft.crash.CrashReport;
 import net.minecraft.crash.CrashReportCategory;
+import net.minecraft.util.Util;
+import net.minecraftforge.fml.common.versioning.ComparableVersion;
 import org.apache.commons.exec.CommandLine;
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.io.output.TeeOutputStream;
 import org.lwjgl.util.ReadableDimension;
 
-import java.io.*;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
 import java.nio.channels.Channels;
 import java.nio.channels.WritableByteChannel;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 
+import static com.replaymod.render.ReplayModRender.LOGGER;
 import static org.apache.commons.lang3.Validate.isTrue;
 
 public class VideoWriter implements FrameConsumer<RGBFrame> {
@@ -46,8 +56,8 @@ public class VideoWriter implements FrameConsumer<RGBFrame> {
                     .replace("%BITRATE%", String.valueOf(settings.getBitRate()))
                     .replace("%FILTERS%", settings.getVideoFilters());
 
-        String executable = settings.getExportCommand().isEmpty() ? "ffmpeg" : settings.getExportCommand();
+        String executable = settings.getExportCommand().isEmpty() ? findFFmpeg() : settings.getExportCommand();
-        System.out.println("Starting " + settings.getExportCommand() + " with args: " + commandArgs);
+        System.out.println("Starting " + executable + " with args: " + commandArgs);
         String[] cmdline = new CommandLine(executable).addArguments(commandArgs).toStrings();
         process = new ProcessBuilder(cmdline).directory(outputFolder).start();
         File exportLogFile = new File(Minecraft.getMinecraft().mcDataDir, "export.log");
@@ -58,6 +68,54 @@ public class VideoWriter implements FrameConsumer<RGBFrame> {
         channel = Channels.newChannel(outputStream);
     }
 
+    private String findFFmpeg() {
+        switch (Util.getOSType()) {
+            case WINDOWS:
+                // Allow windows users to unpack the ffmpeg archive into a sub-folder of their .minecraft folder
+                File inDotMinecraft = new File(Minecraft.getMinecraft().mcDataDir, "ffmpeg/bin/ffmpeg.exe");
+                if (inDotMinecraft.exists()) {
+                    LOGGER.debug("FFmpeg found in .minecraft/ffmpeg");
+                    return inDotMinecraft.getAbsolutePath();
+                }
+                break;
+            case OSX:
+                // The PATH doesn't seem to be set as expected on OSX, therefore we check some common locations ourselves
+                for (String path : new String[]{"/usr/local/bin/ffmpeg", "/usr/bin/ffmpeg"}) {
+                    File file = new File(path);
+                    if (file.exists()) {
+                        LOGGER.debug("Found FFmpeg at {}", path);
+                        return path;
+                    } else {
+                        LOGGER.debug("FFmpeg not located at {}", path);
+                    }
+                }
+                // Homebrew doesn't seem to reliably symlink its installed binaries either
+                File homebrewFolder = new File("/usr/local/Cellar/ffmpeg");
+                String[] homebrewVersions = homebrewFolder.list();
+                if (homebrewVersions != null) {
+                    Optional<File> latestOpt = Arrays.stream(homebrewVersions)
+                            .map(ComparableVersion::new) // Convert file name to comparable version
+                            .sorted(Comparator.reverseOrder()) // Sort for latest version
+                            .map(ComparableVersion::toString) // Convert back to file name
+                            .map(v -> new File(new File(homebrewFolder, v), "bin/ffmpeg")) // Convert to binary files
+                            .filter(File::exists) // Filter invalid installations (missing executable)
+                            .findFirst(); // Take first one
+                    if (latestOpt.isPresent()) {
+                        File latest = latestOpt.get();
+                        LOGGER.debug("Found {} versions of FFmpeg installed with homebrew, chose {}",
+                                homebrewVersions.length, latest);
+                        return latest.getAbsolutePath();
+                    }
+                }
+                break;
+            case LINUX: // Linux users are entrusted to have their PATH configured correctly (most package manager do this)
+            case SOLARIS: // Never heard of anyone running this mod on Solaris having any problems
+            case UNKNOWN: // Unknown OS, just try to use "ffmpeg"
+        }
+        LOGGER.debug("Using default FFmpeg executable");
+        return "ffmpeg";
+    }
+
     @Override
     public void close() throws IOException {
         IOUtils.closeQuietly(outputStream);