diff --git a/src/ImageSharp/Formats/WebP/VP8BandProbas.cs b/src/ImageSharp/Formats/WebP/VP8BandProbas.cs
new file mode 100644
index 0000000000..6a48eef55b
--- /dev/null
+++ b/src/ImageSharp/Formats/WebP/VP8BandProbas.cs
@@ -0,0 +1,18 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.WebP
+{
+    /// <summary>
+    /// All the probabilities associated to one band.
+    /// </summary>
+    internal class Vp8BandProbas
+    {
+        public Vp8BandProbas()
+        {
+            this.Probabilities = new Vp8ProbaArray[WebPConstants.NumCtx];
+        }
+
+        public Vp8ProbaArray[] Probabilities { get; }
+    }
+}
diff --git a/src/ImageSharp/Formats/WebP/Vp8BitReader.cs b/src/ImageSharp/Formats/WebP/Vp8BitReader.cs
index 5264f5bc1e..4fee28d39b 100644
--- a/src/ImageSharp/Formats/WebP/Vp8BitReader.cs
+++ b/src/ImageSharp/Formats/WebP/Vp8BitReader.cs
@@ -46,23 +46,19 @@ namespace SixLabors.ImageSharp.Formats.WebP
         /// </summary>
         private long pos;
 
+        public int Pos { get { return (int)pos; } }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="Vp8BitReader"/> class.
         /// </summary>
         /// <param name="inputStream">The input stream to read from.</param>
         /// <param name="imageDataSize">The raw image data size in bytes.</param>
         /// <param name="memoryAllocator">Used for allocating memory during reading data from the stream.</param>
-        public Vp8BitReader(Stream inputStream, uint imageDataSize, MemoryAllocator memoryAllocator)
+        /// <param name="startPos">Start index in the data array. Defaults to 0.</param>
+        public Vp8BitReader(Stream inputStream, uint imageDataSize, MemoryAllocator memoryAllocator, int startPos = 0)
         {
             this.ReadImageDataFromStream(inputStream, (int)imageDataSize, memoryAllocator);
-
-            this.range = 255 - 1;
-            this.value = 0;
-            this.bits = -8; // to load the very first 8bits.
-            this.eof = false;
-            this.pos = 0;
-
-            this.LoadNewBytes();
+            this.InitBitreader(startPos);
         }
 
         public int GetBit(int prob)
@@ -124,6 +120,17 @@ namespace SixLabors.ImageSharp.Formats.WebP
             return this.ReadValue(1) != 0 ? -value : value;
         }
 
+        private void InitBitreader(int pos = 0)
+        {
+            this.range = 255 - 1;
+            this.value = 0;
+            this.bits = -8; // to load the very first 8bits.
+            this.eof = false;
+            this.pos = 0;
+
+            this.LoadNewBytes();
+        }
+
         private void LoadNewBytes()
         {
             if (this.pos < this.Data.Length)
diff --git a/src/ImageSharp/Formats/WebP/Vp8Proba.cs b/src/ImageSharp/Formats/WebP/Vp8Proba.cs
new file mode 100644
index 0000000000..ac635cf48d
--- /dev/null
+++ b/src/ImageSharp/Formats/WebP/Vp8Proba.cs
@@ -0,0 +1,23 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.WebP
+{
+    /// <summary>
+    /// Data for all frame-persistent probabilities.
+    /// </summary>
+    internal class Vp8Proba
+    {
+        private const int MbFeatureTreeProbs = 3;
+
+        public Vp8Proba()
+        {
+            this.Segments = new uint[MbFeatureTreeProbs];
+            this.Bands = new Vp8BandProbas[WebPConstants.NumTypes, WebPConstants.NumBands];
+        }
+
+        public uint[] Segments { get; }
+
+        public Vp8BandProbas[,] Bands { get; }
+    }
+}
diff --git a/src/ImageSharp/Formats/WebP/Vp8ProbaArray.cs b/src/ImageSharp/Formats/WebP/Vp8ProbaArray.cs
new file mode 100644
index 0000000000..0e7defd4a8
--- /dev/null
+++ b/src/ImageSharp/Formats/WebP/Vp8ProbaArray.cs
@@ -0,0 +1,18 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.WebP
+{
+    /// <summary>
+    /// Probabilities associated to one of the contexts.
+    /// </summary>
+    internal class Vp8ProbaArray
+    {
+        public Vp8ProbaArray()
+        {
+            this.Probabilities = new uint[WebPConstants.NumProbas];
+        }
+
+        public uint[] Probabilities { get; }
+    }
+}
diff --git a/src/ImageSharp/Formats/WebP/WebPConstants.cs b/src/ImageSharp/Formats/WebP/WebPConstants.cs
index fe9d93308a..dfef15260e 100644
--- a/src/ImageSharp/Formats/WebP/WebPConstants.cs
+++ b/src/ImageSharp/Formats/WebP/WebPConstants.cs
@@ -5,6 +5,9 @@ using System.Collections.Generic;
 
 namespace SixLabors.ImageSharp.Formats.WebP
 {
+    /// <summary>
+    /// Constants used for decoding VP8 and VP8L bitstreams.
+    /// </summary>
     internal static class WebPConstants
     {
         /// <summary>
@@ -105,11 +108,25 @@ namespace SixLabors.ImageSharp.Formats.WebP
                                                          NumDistanceCodes
         };
 
-        // VP8 constants
+        // VP8 constants from here on
         public const int NumMbSegments = 4;
 
         public const int MaxNumPartitions = 8;
 
+        public const int NumTypes = 4;
+
+        public const int NumBands = 8;
+
+        public const int NumProbas = 11;
+
+        public const int NumCtx = 3;
+
+        // Paragraph 9.9
+        public static readonly int[] Bands =
+        {
+            0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 0
+        };
+
         // Paragraph 14.1
         public static readonly int[] DcTable =
         {
@@ -152,10 +169,281 @@ namespace SixLabors.ImageSharp.Formats.WebP
             249, 254, 259, 264, 269, 274, 279, 284
         };
 
-        // Paragraph 9.9
-        public static readonly int[] Bands =
+        // Paragraph 13
+        public static readonly byte[,,,] CoeffsUpdateProba =
         {
-            0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 0
+          { { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 176, 246, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 223, 241, 252, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 249, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 244, 252, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 234, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 246, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 239, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 251, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 251, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 254, 253, 255, 254, 255, 255, 255, 255, 255, 255 },
+              { 250, 255, 254, 255, 254, 255, 255, 255, 255, 255, 255 },
+              { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            }
+          },
+          { { { 217, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 225, 252, 241, 253, 255, 255, 254, 255, 255, 255, 255 },
+              { 234, 250, 241, 250, 253, 255, 253, 254, 255, 255, 255 }
+            },
+            { { 255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 223, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 238, 253, 254, 254, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 249, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 253, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 247, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 252, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            }
+          },
+          { { { 186, 251, 250, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 234, 251, 244, 254, 255, 255, 255, 255, 255, 255, 255 },
+              { 251, 251, 243, 253, 254, 255, 254, 255, 255, 255, 255 }
+            },
+            { { 255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 236, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 251, 253, 253, 254, 254, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 254, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 254, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            }
+          },
+          { { { 248, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 250, 254, 252, 254, 255, 255, 255, 255, 255, 255, 255 },
+              { 248, 254, 249, 253, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 246, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 252, 254, 251, 254, 254, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 254, 252, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 248, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 253, 255, 254, 254, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 245, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 253, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 251, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 252, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 252, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 249, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 255, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            },
+            { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
+              { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
+            }
+          }
+        };
+
+        // Paragraph 13.5: Default Token Probability Table.
+        public static readonly byte[,,,] DefaultCoeffsProba =
+        {
+          {
+            { { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
+              { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
+              { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 }
+            },
+            { { 253, 136, 254, 255, 228, 219, 128, 128, 128, 128, 128 },
+              { 189, 129, 242, 255, 227, 213, 255, 219, 128, 128, 128 },
+              { 106, 126, 227, 252, 214, 209, 255, 255, 128, 128, 128 }
+            },
+            { { 1, 98, 248, 255, 236, 226, 255, 255, 128, 128, 128 },
+              { 181, 133, 238, 254, 221, 234, 255, 154, 128, 128, 128 },
+              { 78, 134, 202, 247, 198, 180, 255, 219, 128, 128, 128 },
+            },
+            { { 1, 185, 249, 255, 243, 255, 128, 128, 128, 128, 128 },
+              { 184, 150, 247, 255, 236, 224, 128, 128, 128, 128, 128 },
+              { 77, 110, 216, 255, 236, 230, 128, 128, 128, 128, 128 },
+            },
+            { { 1, 101, 251, 255, 241, 255, 128, 128, 128, 128, 128 },
+              { 170, 139, 241, 252, 236, 209, 255, 255, 128, 128, 128 },
+              { 37, 116, 196, 243, 228, 255, 255, 255, 128, 128, 128 }
+            },
+            { { 1, 204, 254, 255, 245, 255, 128, 128, 128, 128, 128 },
+              { 207, 160, 250, 255, 238, 128, 128, 128, 128, 128, 128 },
+              { 102, 103, 231, 255, 211, 171, 128, 128, 128, 128, 128 }
+            },
+            { { 1, 152, 252, 255, 240, 255, 128, 128, 128, 128, 128 },
+              { 177, 135, 243, 255, 234, 225, 128, 128, 128, 128, 128 },
+              { 80, 129, 211, 255, 194, 224, 128, 128, 128, 128, 128 }
+            },
+            { { 1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
+              { 246, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
+              { 255, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 }
+            }
+          },
+          {
+            { { 198, 35, 237, 223, 193, 187, 162, 160, 145, 155, 62 },
+              { 131, 45, 198, 221, 172, 176, 220, 157, 252, 221, 1 },
+              { 68, 47, 146, 208, 149, 167, 221, 162, 255, 223, 128 }
+            },
+            { { 1, 149, 241, 255, 221, 224, 255, 255, 128, 128, 128 },
+              { 184, 141, 234, 253, 222, 220, 255, 199, 128, 128, 128 },
+              { 81, 99, 181, 242, 176, 190, 249, 202, 255, 255, 128 }
+            },
+            { { 1, 129, 232, 253, 214, 197, 242, 196, 255, 255, 128 },
+              { 99, 121, 210, 250, 201, 198, 255, 202, 128, 128, 128 },
+              { 23, 91, 163, 242, 170, 187, 247, 210, 255, 255, 128 }
+            },
+            { { 1, 200, 246, 255, 234, 255, 128, 128, 128, 128, 128 },
+              { 109, 178, 241, 255, 231, 245, 255, 255, 128, 128, 128 },
+              { 44, 130, 201, 253, 205, 192, 255, 255, 128, 128, 128 }
+            },
+            { { 1, 132, 239, 251, 219, 209, 255, 165, 128, 128, 128 },
+              { 94, 136, 225, 251, 218, 190, 255, 255, 128, 128, 128 },
+              { 22, 100, 174, 245, 186, 161, 255, 199, 128, 128, 128 }
+            },
+            { { 1, 182, 249, 255, 232, 235, 128, 128, 128, 128, 128 },
+              { 124, 143, 241, 255, 227, 234, 128, 128, 128, 128, 128 },
+              { 35, 77, 181, 251, 193, 211, 255, 205, 128, 128, 128 }
+            },
+            { { 1, 157, 247, 255, 236, 231, 255, 255, 128, 128, 128 },
+              { 121, 141, 235, 255, 225, 227, 255, 255, 128, 128, 128 },
+              { 45, 99, 188, 251, 195, 217, 255, 224, 128, 128, 128 }
+            },
+            { { 1, 1, 251, 255, 213, 255, 128, 128, 128, 128, 128 },
+              { 203, 1, 248, 255, 255, 128, 128, 128, 128, 128, 128 },
+              { 137, 1, 177, 255, 224, 255, 128, 128, 128, 128, 128 }
+            }
+          },
+          { { { 253, 9, 248, 251, 207, 208, 255, 192, 128, 128, 128 },
+              { 175, 13, 224, 243, 193, 185, 249, 198, 255, 255, 128 },
+              { 73, 17, 171, 221, 161, 179, 236, 167, 255, 234, 128 }
+            },
+            { { 1, 95, 247, 253, 212, 183, 255, 255, 128, 128, 128 },
+              { 239, 90, 244, 250, 211, 209, 255, 255, 128, 128, 128 },
+              { 155, 77, 195, 248, 188, 195, 255, 255, 128, 128, 128 }
+            },
+            { { 1, 24, 239, 251, 218, 219, 255, 205, 128, 128, 128 },
+              { 201, 51, 219, 255, 196, 186, 128, 128, 128, 128, 128 },
+              { 69, 46, 190, 239, 201, 218, 255, 228, 128, 128, 128 }
+            },
+            { { 1, 191, 251, 255, 255, 128, 128, 128, 128, 128, 128 },
+              { 223, 165, 249, 255, 213, 255, 128, 128, 128, 128, 128 },
+              { 141, 124, 248, 255, 255, 128, 128, 128, 128, 128, 128 }
+            },
+            { { 1, 16, 248, 255, 255, 128, 128, 128, 128, 128, 128 },
+              { 190, 36, 230, 255, 236, 255, 128, 128, 128, 128, 128 },
+              { 149, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
+            },
+            { { 1, 226, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
+              { 247, 192, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
+              { 240, 128, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
+            },
+            { { 1, 134, 252, 255, 255, 128, 128, 128, 128, 128, 128 },
+              { 213, 62, 250, 255, 255, 128, 128, 128, 128, 128, 128 },
+              { 55, 93, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
+            },
+            { { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
+              { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
+              { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 }
+            }
+          },
+          {
+            { { 202, 24, 213, 235, 186, 191, 220, 160, 240, 175, 255 },
+              { 126, 38, 182, 232, 169, 184, 228, 174, 255, 187, 128 },
+              { 61, 46, 138, 219, 151, 178, 240, 170, 255, 216, 128 }
+            },
+            { { 1, 112, 230, 250, 199, 191, 247, 159, 255, 255, 128 },
+              { 166, 109, 228, 252, 211, 215, 255, 174, 128, 128, 128 },
+              { 39, 77, 162, 232, 172, 180, 245, 178, 255, 255, 128 }
+            },
+            { { 1, 52, 220, 246, 198, 199, 249, 220, 255, 255, 128 },
+              { 124, 74, 191, 243, 183, 193, 250, 221, 255, 255, 128 },
+              { 24, 71, 130, 219, 154, 170, 243, 182, 255, 255, 128 }
+            },
+            { { 1, 182, 225, 249, 219, 240, 255, 224, 128, 128, 128 },
+              { 149, 150, 226, 252, 216, 205, 255, 171, 128, 128, 128 },
+              { 28, 108, 170, 242, 183, 194, 254, 223, 255, 255, 128 }
+            },
+            { { 1, 81, 230, 252, 204, 203, 255, 192, 128, 128, 128 },
+              { 123, 102, 209, 247, 188, 196, 255, 233, 128, 128, 128 },
+              { 20, 95, 153, 243, 164, 173, 255, 203, 128, 128, 128 }
+            },
+            { { 1, 222, 248, 255, 216, 213, 128, 128, 128, 128, 128 },
+              { 168, 175, 246, 252, 235, 205, 255, 255, 128, 128, 128 },
+              { 47, 116, 215, 255, 211, 212, 255, 255, 128, 128, 128 }
+            },
+            { { 1, 121, 236, 253, 212, 214, 255, 255, 128, 128, 128 },
+              { 141, 84, 213, 252, 201, 202, 255, 219, 128, 128, 128 },
+              { 42, 80, 160, 240, 162, 185, 255, 205, 128, 128, 128 }
+            },
+            { { 1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
+              { 244, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
+              { 238, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
+            }
+          }
         };
     }
 }
diff --git a/src/ImageSharp/Formats/WebP/WebPDecoderCore.cs b/src/ImageSharp/Formats/WebP/WebPDecoderCore.cs
index 35eed2ed72..89f54dec6b 100644
--- a/src/ImageSharp/Formats/WebP/WebPDecoderCore.cs
+++ b/src/ImageSharp/Formats/WebP/WebPDecoderCore.cs
@@ -373,8 +373,9 @@ namespace SixLabors.ImageSharp.Formats.WebP
 
             // Paragraph 9.3: Parse the segment header.
             var vp8SegmentHeader = new Vp8SegmentHeader();
+            var proba = new Vp8Proba();
             vp8SegmentHeader.UseSegment = bitReader.ReadBool();
-            bool hasValue = false;
+            bool hasValue;
             if (vp8SegmentHeader.UseSegment)
             {
                 vp8SegmentHeader.UpdateMap = bitReader.ReadBool();
@@ -398,10 +399,18 @@ namespace SixLabors.ImageSharp.Formats.WebP
 
                     if (vp8SegmentHeader.UpdateMap)
                     {
-                        // TODO: Read VP8Proba
+                        for (int s = 0; s < proba.Segments.Length; ++s)
+                        {
+                            hasValue = bitReader.ReadBool();
+                            proba.Segments[s] = hasValue ? bitReader.ReadValue(8) : 255;
+                        }
                     }
                 }
             }
+            else
+            {
+                vp8SegmentHeader.UpdateMap = false;
+            }
 
             // Paragraph 9.4: Parse the filter specs.
             var vp8FilterHeader = new Vp8FilterHeader();
@@ -442,8 +451,13 @@ namespace SixLabors.ImageSharp.Formats.WebP
             int numPartsMinusOne = (1 << (int)bitReader.ReadValue(2)) - 1;
             int lastPart = numPartsMinusOne;
             // TODO: check if we have enough data available here, throw exception if not
+            int partStart = bitReader.Pos + (lastPart * 3);
+            for (int p = 0; p < lastPart; ++p)
+            {
+                // int psize = sz[0] | (sz[1] << 8) | (sz[2] << 16);
+            }
 
-            // Paragraph 9.6: Dequantization Indices
+            // Paragraph 9.6: Dequantization Indices.
             int baseQ0 = (int)bitReader.ReadValue(7);
             hasValue = bitReader.ReadBool();
             int dqy1Dc = hasValue ? bitReader.ReadSignedValue(4) : 0;
@@ -499,6 +513,39 @@ namespace SixLabors.ImageSharp.Formats.WebP
                 m.UvQuant = q + dquvAc;
             }
 
+            // Ignore the value of update_proba
+            bitReader.ReadBool();
+
+            // Parse probabilities.
+            for (int t = 0; t < WebPConstants.NumTypes; ++t)
+            {
+                for (int b = 0; b < WebPConstants.NumBands; ++b)
+                {
+                    for (int c = 0; c < WebPConstants.NumCtx; ++c)
+                    {
+                        for (int p = 0; p < WebPConstants.NumProbas; ++p)
+                        {
+                            var prob = WebPConstants.CoeffsUpdateProba[t, b, c, p];
+                            int v = bitReader.GetBit(prob) == 0 ? (int)bitReader.ReadValue(8) : WebPConstants.DefaultCoeffsProba[t, b, c, p];
+                            proba.Bands[t, b].Probabilities[c].Probabilities[p] = (uint)v;
+                        }
+                    }
+                }
+
+                for (int b = 0; b < 16 + 1; ++b)
+                {
+                    // TODO: This needs to be reviewed and fixed.
+                    // proba->bands_ptr_[t][b] = &proba->bands_[t][kBands[b]];
+                }
+            }
+
+            // TODO: those values needs to be stored somewhere
+            bool useSkipProba = bitReader.ReadBool();
+            if (useSkipProba)
+            {
+                var skipP = bitReader.ReadValue(8);
+            }
+
             return new WebPImageInfo()
                    {
                        Width = width,