diff --git a/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/LZWDecoder.java b/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/LZWDecoder.java
index 0d76ab1f..bf573fa9 100644
--- a/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/LZWDecoder.java
+++ b/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/LZWDecoder.java
@@ -35,12 +35,14 @@ import java.io.IOException;
 import java.io.InputStream;
 
 /**
- * Implements Lempel-Ziv & Welch (LZW) decompression.
+ * Lempel–Ziv–Welch (LZW) decompression. LZW is a universal loss-less data compression algorithm
+ * created by Abraham Lempel, Jacob Ziv, and Terry Welch.
  * Inspired by libTiff's LZW decompression.
  *
  * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
  * @author last modified by $Author: haraldk$
  * @version $Id: LZWDecoder.java,v 1.0 08.05.12 21:11 haraldk Exp$
+ * @see <a href="http://en.wikipedia.org/wiki/Lempel%E2%80%93Ziv%E2%80%93Welch">LZW (Wikipedia)</a>
  */
 abstract class LZWDecoder implements Decoder {
     /** Clear: Re-initialize tables. */
@@ -51,6 +53,8 @@ abstract class LZWDecoder implements Decoder {
     private static final int MIN_BITS = 9;
     private static final int MAX_BITS = 12;
 
+    private static final int TABLE_SIZE = 1 << MAX_BITS;
+
     private final boolean compatibilityMode;
 
     private final String[] table;
@@ -68,7 +72,7 @@ abstract class LZWDecoder implements Decoder {
     protected LZWDecoder(final boolean compatibilityMode) {
         this.compatibilityMode = compatibilityMode;
 
-        table = new String[compatibilityMode ? 4096 + 1024 : 4096]; // libTiff adds 1024 "for compatibility"...
+        table = new String[compatibilityMode ? TABLE_SIZE + 1024 : TABLE_SIZE]; // libTiff adds 1024 "for compatibility"...
 
         // First 258 entries of table is always fixed
         for (int i = 0; i < 256; i++) {
diff --git a/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/YCbCrUpsamplerStream.java b/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/YCbCrUpsamplerStream.java
index e18bd152..dc193438 100644
--- a/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/YCbCrUpsamplerStream.java
+++ b/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/YCbCrUpsamplerStream.java
@@ -28,6 +28,8 @@
 
 package com.twelvemonkeys.imageio.plugins.tiff;
 
+import com.twelvemonkeys.lang.Validate;
+
 import java.awt.image.DataBufferByte;
 import java.awt.image.Raster;
 import java.io.EOFException;
@@ -64,8 +66,8 @@ final class YCbCrUpsamplerStream extends FilterInputStream {
     int bufferLength;
     int bufferPos;
 
-    public YCbCrUpsamplerStream(InputStream stream, int[] chromaSub, int yCbCrPos, int columns, double[] coefficients) {
-        super(stream);
+    public YCbCrUpsamplerStream(final InputStream stream, final int[] chromaSub, final int yCbCrPos, final int columns, final double[] coefficients) {
+        super(Validate.notNull(stream, "stream"));
 
         this.horizChromaSub = chromaSub[0];
         this.vertChromaSub = chromaSub[1];
@@ -94,7 +96,7 @@ final class YCbCrUpsamplerStream extends FilterInputStream {
             int read;
 
             // This *SHOULD* read an entire row of units into the buffer, otherwise decodeRows will throw EOFException
-            while (pos < buffer.length && (read = super.read(buffer, pos, buffer.length - pos)) > 0) {
+            while (pos < buffer.length && (read = in.read(buffer, pos, buffer.length - pos)) > 0) {
                 pos += read;
             }
 
@@ -168,7 +170,7 @@ final class YCbCrUpsamplerStream extends FilterInputStream {
             }
         }
 
-        return decodedRows[decodedPos++];
+        return decodedRows[decodedPos++] & 0xff;
     }
 
     @Override