/// <summary>Opens an AVI file and creates a GetFrame object</summary>
/// <param name="fileName">Name of the AVI file</param>
public void Open(string fileName)
{
//Intitialize AVI library
Avi.AVIFileInit();
//Open the file
int result = Avi.AVIFileOpen(
ref aviFile, fileName,
Avi.OF_SHARE_DENY_WRITE, 0);
if (result != 0)
{
throw new Exception("Exception in AVIFileOpen: " + result.ToString());
}
//Get the video stream
result = Avi.AVIFileGetStream(
aviFile,
out aviStream,
Avi.StreamtypeVIDEO, 0);
if (result != 0)
{
throw new Exception("Exception in AVIFileGetStream: " + result.ToString());
}
firstFrame = Avi.AVIStreamStart(aviStream.ToInt32());
countFrames = Avi.AVIStreamLength(aviStream.ToInt32());
streamInfo = new Avi.AVISTREAMINFO();
result = Avi.AVIStreamInfo(aviStream.ToInt32(), ref streamInfo, Marshal.SizeOf(streamInfo));
if (result != 0)
{
throw new Exception("Exception in AVIStreamInfo: " + result.ToString());
}
//Open frames
Avi.BITMAPINFOHEADER bih = new Avi.BITMAPINFOHEADER();
bih.biBitCount = 24;
bih.biClrImportant = 0;
bih.biClrUsed = 0;
bih.biCompression = 0; //BI_RGB;
bih.biHeight = (Int32)streamInfo.rcFrame.bottom;
bih.biWidth = (Int32)streamInfo.rcFrame.right;
bih.biPlanes = 1;
bih.biSize = (UInt32)Marshal.SizeOf(bih);
bih.biXPelsPerMeter = 0;
bih.biYPelsPerMeter = 0;
getFrameObject = Avi.AVIStreamGetFrameOpen(aviStream, ref bih); //force function to return 24bit DIBS
//getFrameObject = Avi.AVIStreamGetFrameOpen(aviStream, 0); //return any bitmaps
if (getFrameObject == 0)
{
throw new Exception("Exception in AVIStreamGetFrameOpen!");
}
}
/// <summary>Creates a new video stream in the AVI file</summary>
private void CreateStream()
{
Avi.AVISTREAMINFO strhdr = new Avi.AVISTREAMINFO();
strhdr.fccType = fccType;
strhdr.fccHandler = fccHandler;
strhdr.dwScale = 1;
strhdr.dwRate = frameRate;
strhdr.dwSuggestedBufferSize = (UInt32)(height * stride);
strhdr.dwQuality = 10000; //highest quality! Compression destroys the hidden message
strhdr.rcFrame.bottom = (UInt32)height;
strhdr.rcFrame.right = (UInt32)width;
strhdr.szName = new UInt16[64];
int result = Avi.AVIFileCreateStream(aviFile, out aviStream, ref strhdr);
if (result != 0)
{
throw new Exception("Error in AVIFileCreateStream: " + result.ToString());
}
//define the image format
Avi.BITMAPINFOHEADER bi = new Avi.BITMAPINFOHEADER();
bi.biSize = (UInt32)Marshal.SizeOf(bi);
bi.biWidth = (Int32)width;
bi.biHeight = (Int32)height;
bi.biPlanes = 1;
bi.biBitCount = 32;
bi.biSizeImage = (UInt32)(stride * height);
oldStream = aviStream;
aviStream = CreateCompressedStream(aviStream);
result = Avi.AVIStreamSetFormat(aviStream, 0, ref bi, Marshal.SizeOf(bi));
if (result != 0)
{
throw new Exception("Error in AVIStreamSetFormat: " + result.ToString());
}
}
/// <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 = 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(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
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);
//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();
}
