diff --git a/source/InputStream.cpp b/source/InputStream.cpp
index e67064c..be2f955 100755
--- a/source/InputStream.cpp
+++ b/source/InputStream.cpp
@@ -39,7 +39,7 @@ InputStream::InputStream()
   m_uiWidth = 0;
   m_uiHeight = 0;
   m_uiTotalFrameNum = 0;
-  m_uiCurrFrameNum = 0;
+  m_iCurrFrameNum = -1;
   m_iErrorStatus = 0;
   m_iPixelFormat = -1;
 
@@ -137,9 +137,12 @@ Void InputStream::init( QString filename, UInt width, UInt height, Int input_for
   m_cStreamInformationString = QString( "[" );
 
 #ifdef USE_FFMPEG
-  avStatus = m_cLibAvContext.initAvFormat( m_cFilename.toLocal8Bit().data(), m_uiWidth, m_uiHeight, m_iPixelFormat, m_uiFrameRate );
-  m_cStreamInformationString.append( QString::fromUtf8( m_cLibAvContext.getStreamInformation() ) );
-  m_uiTotalFrameNum = 100;
+  if( QFileInfo( filename ).completeSuffix().compare( QString( "yuv" ) ) )
+  {
+    avStatus = m_cLibAvContext.initAvFormat( m_cFilename.toLocal8Bit().data(), m_uiWidth, m_uiHeight, m_iPixelFormat, m_uiFrameRate );
+    m_cStreamInformationString.append( QString::fromUtf8( m_cLibAvContext.getStreamInformation() ) );
+    m_uiTotalFrameNum = 100;
+  }
 #endif
 
   if( m_uiWidth <= 0 || m_uiHeight <= 0 )
@@ -181,7 +184,7 @@ Void InputStream::init( QString filename, UInt width, UInt height, Int input_for
 
   m_cStreamInformationString.append( QFileInfo( m_cFilename ).fileName() );
 
-  m_uiCurrFrameNum = 0;
+  m_iCurrFrameNum = -1;
   m_iStatus = 1;
 
   return;
@@ -208,15 +211,12 @@ Void InputStream::readFrame()
     return;
   }
 
-  if( m_uiCurrFrameNum < m_uiTotalFrameNum )
-  {
-    m_uiCurrFrameNum++;
-  }
-  else
+  m_iCurrFrameNum++;
+  if( m_iCurrFrameNum >= m_uiTotalFrameNum )
   {
     m_iErrorStatus = END_OF_SEQ;
-    m_uiCurrFrameNum = 0;
-    seekInput( m_uiCurrFrameNum );
+    m_iCurrFrameNum = 0;
+    seekInput( m_iCurrFrameNum );
   }
 
 #ifdef USE_FFMPEG
@@ -292,7 +292,7 @@ Void InputStream::seekInput( Int new_frame_num )
     UInt64 frame_bytes_input = m_uiWidth * m_uiHeight * 1.5;
     UInt64 nbytes_seek = frame_bytes_input * new_frame_num;
     fseek( m_pFile, nbytes_seek, SEEK_SET );
-    m_uiCurrFrameNum = new_frame_num;
+    m_iCurrFrameNum = new_frame_num;
   }
 }
 
diff --git a/source/InputStream.h b/source/InputStream.h
index 9560171..544dc8d 100755
--- a/source/InputStream.h
+++ b/source/InputStream.h
@@ -78,7 +78,7 @@ private:
   UInt m_uiHeight;
   UInt m_uiFrameRate;
   UInt m_uiTotalFrameNum;
-  UInt m_uiCurrFrameNum;
+  Int m_iCurrFrameNum;
 
 public:
   InputStream();
@@ -136,9 +136,9 @@ public:
   {
     return m_uiHeight;
   }
-  UInt getCurrFrameNum()
+  Int getCurrFrameNum()
   {
-    return m_uiCurrFrameNum;
+    return m_iCurrFrameNum;
   }
   UInt getFrameRate()
   {
diff --git a/source/lib/ffmpeg/LibAvContextHandle.h b/source/lib/ffmpeg/LibAvContextHandle.h
index 96e7460..4a35751 100755
--- a/source/lib/ffmpeg/LibAvContextHandle.h
+++ b/source/lib/ffmpeg/LibAvContextHandle.h
@@ -43,8 +43,6 @@ extern "C"
 #include <libavformat/avformat.h>
 }
 
-
-
 #include "TypeDef.h"
 
 namespace plaYUVer
@@ -53,6 +51,10 @@ namespace plaYUVer
 class LibAvContextHandle
 {
 public:
+  LibAvContextHandle() :
+      m_bHasStream( false )
+  {
+  }
   Bool initAvFormat( char* filename, UInt& width, UInt& height, Int& pixel_format, UInt& frame_rate );
   Void closeAvFormat();
   Bool decodeAvFormat();