/// <summary>Apply a format to a new stream</summary> /// <param name="aviStream">The IAVISTREAM</param> /// <remarks> /// The format must be set before the first frame can be written, /// and it cannot be changed later. /// </remarks> private void SetFormat(IntPtr aviStream, int writePosition) { Avi.BITMAPINFO bi = new Avi.BITMAPINFO(); bi.bmiHeader.biWidth = width; bi.bmiHeader.biHeight = height; bi.bmiHeader.biPlanes = 1; bi.bmiHeader.biBitCount = countBitsPerPixel; bi.bmiHeader.biSizeImage = frameSize; bi.bmiHeader.biSize = Marshal.SizeOf(bi.bmiHeader); if (countBitsPerPixel < 24) { bi.bmiHeader.biClrUsed = this.palette.Length; bi.bmiHeader.biClrImportant = this.palette.Length; bi.bmiColors = new Avi.RGBQUAD[this.palette.Length]; this.palette.CopyTo(bi.bmiColors, 0); bi.bmiHeader.biSize += bi.bmiColors.Length * Avi.RGBQUAD_SIZE; } int result = Avi.AVIStreamSetFormat(aviStream, writePosition, ref bi, bi.bmiHeader.biSize); if (result != 0) { throw new Exception("Error in VideoStreamSetFormat: " + result.ToString("X")); } }
/// <summary>Initialize a VideoStream for an existing stream</summary> /// <param name="aviFile">The file that contains the stream</param> /// <param name="aviStream">An IAVISTREAM from [aviFile]</param> public VideoStream(int aviFile, IntPtr aviStream) { this.aviFile = aviFile; this.aviStream = aviStream; Avi.AVISTREAMINFO streamInfo = GetStreamInfo(aviStream); //Avi.BITMAPINFOHEADER bih = new Avi.BITMAPINFOHEADER(); //int size = Marshal.SizeOf(bih); Avi.BITMAPINFO bih = new Avi.BITMAPINFO(); int size = Marshal.SizeOf(bih.bmiHeader); Avi.AVIStreamReadFormat(aviStream, 0, ref bih, ref size); if (bih.bmiHeader.biBitCount < 24) { size = Marshal.SizeOf(bih.bmiHeader) + Avi.PALETTE_SIZE; Avi.AVIStreamReadFormat(aviStream, 0, ref bih, ref size); CopyPalette(bih.bmiColors); } this.frameRate = (float)streamInfo.dwRate / (float)streamInfo.dwScale; this.width = (int)streamInfo.rcFrame.right; this.height = (int)streamInfo.rcFrame.bottom; this.frameSize = bih.bmiHeader.biSizeImage; this.countBitsPerPixel = bih.bmiHeader.biBitCount; this.firstFrame = Avi.AVIStreamStart(aviStream.ToInt32()); this.countFrames = Avi.AVIStreamLength(aviStream.ToInt32()); }
/// <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); Avi.BITMAPINFO bih = new Avi.BITMAPINFO(); int headerSize = Marshal.SizeOf(bih.bmiHeader); //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 bih.bmiColors = this.palette; bih.bmiHeader = (Avi.BITMAPINFOHEADER)Marshal.PtrToStructure(new IntPtr(dib), bih.bmiHeader.GetType()); if (bih.bmiHeader.biSizeImage < 1) { throw new Exception("Exception in VideoStreamGetFrame"); } //copy the image int framePaletteSize = bih.bmiHeader.biClrUsed * Avi.RGBQUAD_SIZE; byte[] bitmapData = new byte[bih.bmiHeader.biSizeImage]; IntPtr dibPointer = new IntPtr(dib + Marshal.SizeOf(bih.bmiHeader) + framePaletteSize); Marshal.Copy(dibPointer, bitmapData, 0, bih.bmiHeader.biSizeImage); //copy bitmap info byte[] bitmapInfo = new byte[Marshal.SizeOf(bih)]; IntPtr ptr = Marshal.AllocHGlobal(bitmapInfo.Length); Marshal.StructureToPtr(bih, ptr, false); Marshal.Copy(ptr, 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.bmiHeader.biSizeImage); //size of file as written to disk bfh.bfReserved1 = 0; bfh.bfReserved2 = 0; bfh.bfOffBits = Marshal.SizeOf(bih) + Marshal.SizeOf(bfh); if (bih.bmiHeader.biBitCount < 8) { //There is a palette between header and pixel data bfh.bfOffBits += bih.bmiHeader.biClrUsed * Avi.RGBQUAD_SIZE; //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); }