private AVIStreamGetFrame ( int pGetFrameObj, int lPos ) : int | ||
pGetFrameObj | int | |
lPos | int | |
return | int |
/// <summary>Export a frame into a bitmap</summary> /// <param name="position">Position of the frame</param> public Bitmap GetBitmap(int position) { if (position > countFrames) { throw new Exception("Invalid frame position: " + position); } Avi.AVISTREAMINFO streamInfo = GetStreamInfo(StreamPointer); //Decompress the frame and return a pointer to the DIB int dib = Avi.AVIStreamGetFrame(getFrameObject, firstFrame + position); //Copy the bitmap header into a managed struct Avi.BITMAPINFOHEADER bih = new Avi.BITMAPINFOHEADER(); bih = (Avi.BITMAPINFOHEADER)Marshal.PtrToStructure(new IntPtr(dib), bih.GetType()); if (bih.biSizeImage < 1) { throw new Exception("Exception in VideoStreamGetFrame"); } //copy the image byte[] bitmapData; int address = dib + Marshal.SizeOf(bih); if (bih.biBitCount < 16) { //copy palette and pixels bitmapData = new byte[bih.biSizeImage + Avi.PALETTE_SIZE]; } else { //copy only pixels bitmapData = new byte[bih.biSizeImage]; } Marshal.Copy(new IntPtr(address), bitmapData, 0, bitmapData.Length); //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(); Marshal.Copy(new IntPtr(address), bitmapInfo, 0, bitmapInfo.Length); Marshal.FreeHGlobal(ptr); //create file header Avi.BITMAPFILEHEADER bfh = new Avi.BITMAPFILEHEADER(); bfh.bfType = Avi.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); if (bih.biBitCount < 16) { //There is a palette between header and pixel data bfh.bfOffBits += Avi.PALETTE_SIZE; } //write a bitmap stream BinaryWriter bw = new BinaryWriter(new MemoryStream()); //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); Bitmap bmp = (Bitmap)Image.FromStream(bw.BaseStream); Bitmap saveableBitmap = new Bitmap(bmp.Width, bmp.Height); Graphics g = Graphics.FromImage(saveableBitmap); g.DrawImage(bmp, 0, 0); g.Dispose(); bmp.Dispose(); bw.Close(); return(saveableBitmap); }