diff --git a/BPTCEncoder/src/ParallelStage.cpp b/BPTCEncoder/src/ParallelStage.cpp
index 345a56a..a3ef7b9 100644
--- a/BPTCEncoder/src/ParallelStage.cpp
+++ b/BPTCEncoder/src/ParallelStage.cpp
@@ -64,13 +64,22 @@
  // This is the total number of blocks in this particular stage.
  uint32 m_NumBlocks;
  */    
-ParallelStage::ParallelStage(BC7ParallelStage stage, const unsigned char *inbuf, unsigned char *outbuf, uint32 numBlocks)
+ParallelStage::ParallelStage(
+  BC7ParallelStage stage,
+  const unsigned char *inbuf,
+  unsigned char *outbuf,
+  uint32 numBlocks,
+  uint32 outBlockSz,
+  uint32 inBlockSz
+)
   : m_Stage(stage)
   , m_InBuf(inbuf)
   , m_OutBuf(outbuf)
   , m_Blocks(new uint32[numBlocks])
   , m_TotalNumBlocks(numBlocks)
   , m_NumBlocks(0)
+  , m_OutBlockSz(outBlockSz)
+  , m_InBlockSz(inBlockSz)
 {
   assert(numBlocks > 0);
 }
@@ -82,6 +91,8 @@ ParallelStage::ParallelStage(const ParallelStage &other)
   , m_Blocks(new uint32[other.m_NumBlocks])
   , m_TotalNumBlocks(other.m_TotalNumBlocks)
   , m_NumBlocks(other.m_NumBlocks)
+  , m_OutBlockSz(other.m_OutBlockSz)
+  , m_InBlockSz(other.m_InBlockSz)
 {
   memcpy(m_Blocks, other.m_Blocks, m_NumBlocks * sizeof(m_Blocks[0]));
 }
@@ -92,14 +103,51 @@ ParallelStage &ParallelStage::operator=(const ParallelStage &other) {
   assert(m_OutBuf == other.m_OutBuf);
   assert(m_TotalNumBlocks == other.m_TotalNumBlocks);
   assert(m_NumBlocks == other.m_NumBlocks);
+  assert(m_OutBlockSz == other.m_OutBlockSz);
+  assert(m_InBlockSz == other.m_InBlockSz);
   
   memcpy(m_Blocks, other.m_Blocks, m_NumBlocks * sizeof(m_Blocks[0]));
   return *this;
 }
-  
 
-void ParallelStage::AddBlock(int blockNum) {
+void ParallelStage::AddBlock(uint32 blockNum) {
   assert(m_NumBlocks < m_TotalNumBlocks);
   
   m_Blocks[m_NumBlocks++] = blockNum;
-}
\ No newline at end of file
+}
+
+uint32 ParallelStage::LoadBlocks(uint32 blockOffset, uint32 numBlocks, unsigned char *dst) {
+
+  if(!dst)
+    return 0;
+
+  if(blockOffset + numBlocks > m_NumBlocks)
+    return 0;
+
+  int lastBlock = blockOffset + numBlocks;
+  for(int i = blockOffset; i < lastBlock; i++)
+  {
+    uint32 block = m_Blocks[i];
+    uint32 bOffset = block * m_InBlockSz;
+    memcpy(dst + ((i - blockOffset) * m_InBlockSz), m_InBuf + bOffset, m_InBlockSz);
+  }
+
+  return 0;
+}
+
+bool ParallelStage::WriteBlocks(uint32 blockOffset, uint32 numBlocks, const unsigned char *src) {
+  if(!src)
+    return false;
+
+  if(blockOffset + numBlocks > m_NumBlocks)
+    return false;
+
+  int lastBlock = blockOffset + numBlocks;
+  for(int i = blockOffset; i < lastBlock; i++) {
+    uint32 block = m_Blocks[i];
+    uint32 bOffset = block * m_OutBlockSz;
+    memcpy(m_OutBuf + bOffset, src + ((i-blockOffset) * m_OutBlockSz), m_OutBlockSz);
+  }
+
+  return true;
+}
diff --git a/BPTCEncoder/src/ParallelStage.h b/BPTCEncoder/src/ParallelStage.h
index 44e049e..54c7393 100644
--- a/BPTCEncoder/src/ParallelStage.h
+++ b/BPTCEncoder/src/ParallelStage.h
@@ -53,28 +53,47 @@ enum BC7ParallelStage {
 
 class ParallelStage {
  public:
-  ParallelStage(BC7ParallelStage stage, const unsigned char *inbuf, unsigned char *outbuf, uint32 numBlocks);
+  ParallelStage(
+    BC7ParallelStage stage,
+    const unsigned char *inbuf,
+    unsigned char *outbuf,
+    uint32 numBlocks,
+    uint32 outBlockSz = 16,
+    uint32 inBlockSz = 64
+  );
   ParallelStage(const ParallelStage &);
   ParallelStage &operator=(const ParallelStage &);
-  
+
   const BC7ParallelStage m_Stage;
-  
-  void AddBlock(int blockNum);
-  
+
+  // Adds the block number to the list of blocks for this parallel stage
+  void AddBlock(uint32 blockNum);
+
+  // Loads the desired number of blocks into the destination buffer. Returns
+  // the number of blocks loaded.
+  uint32 LoadBlocks(uint32 blockOffset, uint32 numBlocks, unsigned char *dst);
+
+  // Writes the block data from src into numBlocks blocks starting from
+  // the block given by blockOffset.
+  bool WriteBlocks(uint32 blockOffset, uint32 numBlocks, const unsigned char *src);
+
  private:
-  
+
   // This is the stream of data that will be used to read the block data.
   const unsigned char *const m_InBuf;
-  
+
   // This is the destination buffer to which the block data will be written to.
   unsigned char *const m_OutBuf;
-  
+
   // This is the array of block offsets that belong to this stage.
   uint32 *m_Blocks;
-  
+
   // This is the total number of blocks in the given image.
   const uint32 m_TotalNumBlocks;
-  
+
   // This is the total number of blocks in this particular stage.
   uint32 m_NumBlocks;
+
+  const uint32 m_OutBlockSz;
+  const uint32 m_InBlockSz;
 };
\ No newline at end of file