diff --git a/source/InputStream.cpp b/source/InputStream.cpp
index 07f36d4..083dcb5 100755
--- a/source/InputStream.cpp
+++ b/source/InputStream.cpp
@@ -109,7 +109,6 @@ QStringList InputStream::supportedPixelFormatList()
 
 Bool InputStream::needFormatDialog( QString filename )
 {
-  return true;
   QString fileExtension = QFileInfo( filename ).completeSuffix();
   if( !fileExtension.compare( QString( "yuv" ) ) )
   {
@@ -130,7 +129,7 @@ Void InputStream::init( QString filename, UInt width, UInt height, Int input_for
   m_iPixelFormat = input_format;
 
 #ifdef USE_FFMPEG
-  Bool avStatus = m_cLibAvContext.initAvFormat( filename, width, height, input_format );
+  Bool avStatus = m_cLibAvContext.initAvFormat( filename, m_uiWidth, m_uiHeight, m_iPixelFormat );
 #endif
 
   if( m_uiWidth <= 0 || m_uiHeight <= 0 )
diff --git a/source/LibAvContextHandle.cpp b/source/LibAvContextHandle.cpp
index 73e08ed..e926a69 100755
--- a/source/LibAvContextHandle.cpp
+++ b/source/LibAvContextHandle.cpp
@@ -24,7 +24,7 @@
 #include "LibAvContextHandle.h"
 
 #ifdef USE_FFMPEG
-  
+
 #include <cstdio>
 
 #include <QtDebug>
@@ -135,6 +135,19 @@ Bool LibAvContextHandle::initAvFormat( QString filename, UInt& width, UInt& heig
     video_dst_bufsize = ret;
   }
 
+  AVCodecContext *in_codec = fmt_ctx->streams[0]->codec;
+  width = in_codec->width;
+  height = in_codec->height;
+  switch( in_codec->pix_fmt )
+  {
+  case AV_PIX_FMT_YUV420P:
+    pixel_format = PlaYUVerFrame::YUV420;
+    break;
+  case AV_PIX_FMT_GRAY8:
+    pixel_format = PlaYUVerFrame::YUV400;
+    break;
+  }
+
   /* dump input information to stderr */
   av_dump_format( fmt_ctx, 0, src_filename, 0 );
   if( !video_stream )