Initial work on detecting video and audio files.

src/org/forkalsrud/album/exif/OggIdentifier.java

@@ -0,0 +1,94 @@
+/**
+ * 
+ */
+package org.forkalsrud.album.exif;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+
+/**
+ * @author knut
+ *
+ */
+public class OggIdentifier {
+
+	static Codec getIdentifier(File f) throws IOException {
+
+		return getIdentifier(new FileInputStream(f));
+	}
+
+	static Codec getIdentifier(InputStream is) throws IOException {
+
+		byte[] header = new byte[1024];
+		int len = is.read(header);
+
+		if (len < 100) {
+			return null;
+		}
+
+		// Make sure the OggS magic marker is there
+		for (int i = 0; i < MAGIC.length; i++) {
+			if (header[i] != MAGIC[i]) {
+				return null;
+			}
+		}
+
+		for (Codec c : CODECS) {
+			if (c.matches(header, 28)) {
+				return c;
+			}
+		}
+		return null;
+	}
+
+	static byte[] MAGIC = "OggS".getBytes();
+
+	static class Codec {
+		byte[] magic;
+		String mimeType;
+		
+		public String getMimeType() {
+			return mimeType;
+		}
+
+		public Codec(String mimeType, char... magic) {
+			this.magic = new byte[magic.length];
+			for (int i = 0; i < magic.length; i++) {
+				this.magic[i] = (byte)magic[i];
+			}
+			this.mimeType = mimeType;
+		}
+
+		public boolean matches(byte[] src, int offset) {
+
+			for (int i = 0; i < magic.length; i++) {
+				if (src[offset + i] != magic[i]) {
+					return false;
+				}
+			}
+			return true;
+		}
+	}
+
+
+	static Codec[] CODECS = new Codec[] {
+		new Codec("video/ogg; codecs=dirac", 'B', 'B', 'C', 'D', '\0'),
+		new Codec("video/ogg; codecs=flac", (char)177, 'F', 'L', 'A', 'C'),
+		new Codec("video/ogg; codecs=theora", (char)0x80, 't', 'h', 'e', 'o', 'r', 'a'),
+		new Codec("audio/ogg; codecs=vorbis", (char)0x01, 'v', 'o', 'r', 'b', 'i', 's'),
+		new Codec("application/ogg; codecs=celt", 'C', 'E', 'L', 'T', ' ', ' ', ' ', ' '),
+		new Codec("application/ogg; codecs=cmml", 'C', 'M', 'M', 'L', '\0', '\0', '\0', '\0'),
+		new Codec("application/ogg; codecs=jng", (char)213, 'J', 'N', 'G', '\r', '\n', ' ', '\n'),
+		new Codec("application/ogg; codecs=kate", (char)0x80, 'k', 'a', 't', 'e', '\0', '\0', '\0'),
+		new Codec("application/ogg; codecs=midi", 'O', 'g', 'g', 'm', 'i', 'd', 'i', '\0'),
+		new Codec("application/ogg; codecs=mng", (char)212, 'M', 'N', 'G', '\r', '\n', ' ', '\n'),
+		new Codec("audio/ogg; codecs=pcm", 'P', 'C', 'M', ' ', ' ', ' ', ' ', ' '),
+		new Codec("application/ogg; codecs=png", (char)212, 'P', 'N', 'G', '\r', '\n', ' ', '\n'),
+		new Codec("audio/ogg; codecs=speex", 'S', 'p', 'e', 'e', 'x', ' ', ' ', ' '),
+		new Codec("video/ogg; codecs=yuv4mpeg", 'Y', 'U', 'V', '4', 'M', 'P', 'E', 'G'),
+	};
+
+}

src/org/forkalsrud/album/exif/OggIdentifierTest.java

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+package org.forkalsrud.album.exif;
+
+import org.forkalsrud.album.exif.OggIdentifier.Codec;
+
+import junit.framework.TestCase;
+
+public class OggIdentifierTest extends TestCase {
+
+	public void testVideoIdentifier() throws Exception {
+
+		Codec codec = OggIdentifier.getIdentifier(getClass().getResourceAsStream("videoheader.ogg"));
+		assertNotNull(codec);
+		assertEquals("video/ogg; codecs=theora", codec.getMimeType());
+	}
+
+	
+	public void testAudioIdentifier() throws Exception {
+
+		Codec codec = OggIdentifier.getIdentifier(getClass().getResourceAsStream("musicheader.ogg"));
+		assertNotNull(codec);
+		assertEquals("audio/ogg; codecs=vorbis", codec.getMimeType());
+	}
+
+
+	public void testInvalidIdentifier() throws Exception {
+
+		Codec codec = OggIdentifier.getIdentifier(getClass().getResourceAsStream("OggIdentifierTest.class"));
+		assertNull(codec);
+	}
+}