/// <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;
}
/// <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());
}
