Separate rendering into its own module

src/main/java/com/replaymod/render/metadata/MetadataInjector.java

@@ -0,0 +1,106 @@
+package com.replaymod.render.metadata;
+
+import com.coremedia.iso.IsoFile;
+import com.coremedia.iso.boxes.*;
+import com.google.common.primitives.Bytes;
+import com.googlecode.mp4parser.BasicContainer;
+import net.minecraftforge.fml.common.FMLLog;
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.IOUtils;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+public class MetadataInjector {
+
+    private static final String STITCHING_SOFTWARE = "Minecraft ReplayMod";
+
+    /*
+     * The Spherical XML is a modified version of https://github.com/google/spatial-media/tree/master/360-Videos-Metadata
+     */
+    private static final String SPHERICAL_XML_HEADER =
+            "<?xml version=\"1.0\"?> " +
+            "<rdf:SphericalVideo xmlns:rdf=" +
+            "\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" xmlns:GSpherical=\"http://ns.google.com/videos/1.0/spherical/\"> ";
+    private static final String SPHERICAL_XML_CONTENTS =
+            "<GSpherical:Spherical>true</GSpherical:Spherical> " +
+            "<GSpherical:Stitched>true</GSpherical:Stitched> " +
+            "<GSpherical:StitchingSoftware>"+STITCHING_SOFTWARE+"</GSpherical:StitchingSoftware> " +
+            "<GSpherical:ProjectionType>equirectangular</GSpherical:ProjectionType> ";
+    private static final String SPHERICAL_XML_FOOTER = "</rdf:SphericalVideo>";
+
+    private static final String XML_360_METADATA = SPHERICAL_XML_HEADER + SPHERICAL_XML_CONTENTS + SPHERICAL_XML_FOOTER;
+
+    /**
+     * These bytes are taken from the variable 'spherical_uuid_id'
+     * in https://github.com/google/spatial-media/tree/master/360-Videos-Metadata
+     */
+    private static final byte[] UUID_BYTES = new byte[] {
+            (byte)0xff, (byte)0xcc, (byte)0x82, (byte)0x63,
+            (byte)0xf8, (byte)0x55, (byte)0x4a, (byte)0x93,
+            (byte)0x88, (byte)0x14, (byte)0x58, (byte)0x7a,
+            (byte)0x02, (byte)0x52, (byte)0x1f, (byte)0xdd
+    };
+
+    private static final byte[] BYTES_360_METADATA = Bytes.concat(UUID_BYTES, XML_360_METADATA.getBytes());
+
+    public static void inject360Metadata(File videoFile) {
+        writeMetadata(videoFile, BYTES_360_METADATA);
+    }
+
+    private static void writeMetadata(File videoFile, byte[] metadata) {
+        File tempFile = null;
+        FileOutputStream videoFileOutputStream = null;
+        IsoFile tempIsoFile = null;
+
+        try {
+            tempFile = File.createTempFile("videoCopy", "mp4");
+            FileUtils.copyFile(videoFile, tempFile);
+
+            tempIsoFile = new IsoFile(tempFile.getAbsolutePath());
+
+            //first, get the "moov" box from the mp4
+            MovieBox moovBox = (MovieBox)getBoxByName(tempIsoFile, "moov");
+            if(moovBox == null) throw new IOException("Could not find moov box inside IsoFile");
+
+            //get the Movie Track to which we will add the Metadata
+            TrackBox trackBox = (TrackBox)getBoxByName(moovBox, "trak");
+            if(trackBox == null) throw new IOException("Could not find trak box inside moov box");
+
+            //create a new UserBox, which actually contains the Metadata bytes
+            UserBox metadataBox = new UserBox(new byte[0]);
+            metadataBox.setData(metadata);
+
+            //add the Metadata UserBox to the Movie Track
+            trackBox.addBox(metadataBox);
+
+            //finally, reduce the Video's FreeBox, whose size we will need
+            //to reduce by the Metadata Box's size to preserve the Video's File size
+            FreeBox freeBox = (FreeBox)getBoxByName(tempIsoFile, "free");
+            if(freeBox == null) throw new IOException("Could not find free box inside IsoFile");
+
+            int freeSize = Math.max(0, freeBox.getData().capacity() - (int)metadataBox.getSize());
+            freeBox.setData(ByteBuffer.allocate(freeSize));
+
+            //save the ISO file to disk
+            videoFileOutputStream = new FileOutputStream(videoFile);
+            tempIsoFile.getBox(videoFileOutputStream.getChannel());
+        } catch(Exception e) {
+            FMLLog.getLogger().error("360 Degree Metadata couldn't be injected", e);
+        } finally {
+            IOUtils.closeQuietly(tempIsoFile);
+            IOUtils.closeQuietly(videoFileOutputStream);
+            FileUtils.deleteQuietly(tempFile);
+        }
+    }
+
+    private static Box getBoxByName(BasicContainer container, String boxName) {
+        for (Box box : container.getBoxes()) {
+            if(box.getType().equals(boxName)) return box;
+        }
+        return null;
+    }
+
+}