diff --git a/mkvparser.cpp b/mkvparser.cpp
index 5043454..e79343c 100644
--- a/mkvparser.cpp
+++ b/mkvparser.cpp
@@ -4853,9 +4853,11 @@ Block::Block(long long start, long long size_, IMkvReader* pReader) :
     long status = pReader->Read(pos, 1, &m_flags);
     assert(status == 0);
 
+#if 0
     const int invisible = int(m_flags & 0x08) >> 3;
     invisible;
     assert(!invisible);  //TODO
+#endif
 
     const int lacing = int(m_flags & 0x06) >> 1;
 
@@ -5135,28 +5137,12 @@ void Block::SetKey(bool bKey)
 }
 
 
-#if 0
-long long Block::GetOffset() const
+bool Block::IsInvisible() const
 {
-  return m_frameOff;
+    return bool(int(m_flags & 0x08) != 0);
 }
 
 
-long Block::GetSize() const
-{
-    return m_frameSize;
-}
-
-long Block::Read(IMkvReader* pReader, unsigned char* buf) const
-{
-    assert(pReader);
-    assert(buf);
-
-    const long hr = pReader->Read(m_frameOff, m_frameSize, buf);
-
-    return hr;
-}
-#else
 int Block::GetFrameCount() const
 {
     return m_frame_count;
@@ -5184,7 +5170,6 @@ long Block::Frame::Read(IMkvReader* pReader, unsigned char* buf) const
     const long status = pReader->Read(pos, len, buf);
     return status;
 }
-#endif
 
 
 }  //end namespace mkvparser
diff --git a/mkvparser.hpp b/mkvparser.hpp
index d0d3ad4..11da814 100644
--- a/mkvparser.hpp
+++ b/mkvparser.hpp
@@ -80,6 +80,7 @@ public:
     long long GetTime(const Cluster*) const;      //absolute, and scaled (ns)
     bool IsKey() const;
     void SetKey(bool);
+    bool IsInvisible() const;
 
     int GetFrameCount() const;  //to index frames: [0, count)
 
@@ -91,26 +92,15 @@ public:
         long Read(IMkvReader*, unsigned char*) const;
     };
 
-#if 0
-    long long GetOffset() const;
-    long GetSize() const;
-    long Read(IMkvReader*, unsigned char*) const;
-#else
     const Frame& GetFrame(int frame_index) const;
-#endif
 
 private:
     long long m_track;   //Track::Number()
     short m_timecode;  //relative to cluster
     unsigned char m_flags;
 
-#if 0
-    long long m_frameOff;
-    long m_frameSize;
-#else
     Frame* m_frames;
     int m_frame_count;
-#endif
 
 };