/// <summary>Exports a frame into a bitmap file</summary>
/// <param name="position">Position of the frame</param>
/// <param name="dstFileName">Name ofthe file to store the bitmap</param>
public void ExportBitmap(int position, String dstFileName)
{
if (position > countFrames)
{
throw new Exception("Invalid frame position");
}
//Decompress the frame and return a pointer to the DIB
int pDib = VFW.AVIStreamGetFrame(getFrameObject, firstFrame + position);
//Copy the bitmap header into a managed struct
BITMAPINFOHEADER bih = new BITMAPINFOHEADER();
bih = (BITMAPINFOHEADER)Marshal.PtrToStructure(new IntPtr(pDib), bih.GetType());
/*if(bih.biBitCount < 24){
* throw new Exception("Not enough colors! DIB color depth is less than 24 bit.");
* }else */
if (bih.biSizeImage < 1)
{
throw new Exception("Exception in AVIStreamGetFrame: Not bitmap decompressed.");
}
//Copy the image
byte[] bitmapData = new byte[bih.biSizeImage];
int address = pDib + Marshal.SizeOf(bih);
for (int offset = 0; offset < bitmapData.Length; offset++)
{
bitmapData[offset] = Marshal.ReadByte(new IntPtr(address));
address++;
}
//Copy bitmap info
byte[] bitmapInfo = new byte[Marshal.SizeOf(bih)];
IntPtr ptr;
ptr = Marshal.AllocHGlobal(bitmapInfo.Length);
Marshal.StructureToPtr(bih, ptr, false);
address = ptr.ToInt32();
for (int offset = 0; offset < bitmapInfo.Length; offset++)
{
bitmapInfo[offset] = Marshal.ReadByte(new IntPtr(address));
address++;
}
//Create file header
BITMAPFILEHEADER bfh = new BITMAPFILEHEADER();
bfh.bfType = Util.BMP_MAGIC_COOKIE;
bfh.bfSize = (Int32)(55 + bih.biSizeImage); //size of file as written to disk
bfh.bfReserved1 = 0;
bfh.bfReserved2 = 0;
bfh.bfOffBits = Marshal.SizeOf(bih) + Marshal.SizeOf(bfh);
//Create or overwrite the destination file
FileStream fs = new FileStream(dstFileName, System.IO.FileMode.Create);
BinaryWriter bw = new BinaryWriter(fs);
//Write header
bw.Write(bfh.bfType);
bw.Write(bfh.bfSize);
bw.Write(bfh.bfReserved1);
bw.Write(bfh.bfReserved2);
bw.Write(bfh.bfOffBits);
//Write bitmap info
bw.Write(bitmapInfo);
//Write bitmap data
bw.Write(bitmapData);
bw.Close();
fs.Close();
}
/// <summary>Exports a frame into a bitmap file</summary>
/// <param name="position">Position of the frame</param>
/// <param name="dstFileName">Name ofthe file to store the bitmap</param>
public void ExportBitmap( int position, String dstFileName ) {
if ( position > countFrames ) {
throw new Exception( "Invalid frame position" );
}
//Decompress the frame and return a pointer to the DIB
int pDib = VFW.AVIStreamGetFrame( getFrameObject, firstFrame + position );
//Copy the bitmap header into a managed struct
BITMAPINFOHEADER bih = new BITMAPINFOHEADER();
bih = (BITMAPINFOHEADER)Marshal.PtrToStructure( new IntPtr( pDib ), bih.GetType() );
/*if(bih.biBitCount < 24){
throw new Exception("Not enough colors! DIB color depth is less than 24 bit.");
}else */
if ( bih.biSizeImage < 1 ) {
throw new Exception( "Exception in AVIStreamGetFrame: Not bitmap decompressed." );
}
//Copy the image
byte[] bitmapData = new byte[bih.biSizeImage];
int address = pDib + Marshal.SizeOf( bih );
for ( int offset = 0; offset < bitmapData.Length; offset++ ) {
bitmapData[offset] = Marshal.ReadByte( new IntPtr( address ) );
address++;
}
//Copy bitmap info
byte[] bitmapInfo = new byte[Marshal.SizeOf( bih )];
IntPtr ptr;
ptr = Marshal.AllocHGlobal( bitmapInfo.Length );
Marshal.StructureToPtr( bih, ptr, false );
address = ptr.ToInt32();
for ( int offset = 0; offset < bitmapInfo.Length; offset++ ) {
bitmapInfo[offset] = Marshal.ReadByte( new IntPtr( address ) );
address++;
}
//Create file header
BITMAPFILEHEADER bfh = new BITMAPFILEHEADER();
bfh.bfType = Util.BMP_MAGIC_COOKIE;
bfh.bfSize = (Int32)(55 + bih.biSizeImage); //size of file as written to disk
bfh.bfReserved1 = 0;
bfh.bfReserved2 = 0;
bfh.bfOffBits = Marshal.SizeOf( bih ) + Marshal.SizeOf( bfh );
//Create or overwrite the destination file
FileStream fs = new FileStream( dstFileName, System.IO.FileMode.Create );
BinaryWriter bw = new BinaryWriter( fs );
//Write header
bw.Write( bfh.bfType );
bw.Write( bfh.bfSize );
bw.Write( bfh.bfReserved1 );
bw.Write( bfh.bfReserved2 );
bw.Write( bfh.bfOffBits );
//Write bitmap info
bw.Write( bitmapInfo );
//Write bitmap data
bw.Write( bitmapData );
bw.Close();
fs.Close();
}
