C#利用AVIFIL32.dll实现图片序列化为视频

using System;
using System.Runtime.InteropServices;
using System.Drawing;
using System.Drawing.Imaging;

namespace org.loon.util
{
    /// <summary>
    /// AVIWriter 的摘要说明，chenpeng,Email:ceponline@yahoo.com.cn。
    /// </summary>
    public class AVIWriter
    {
        const string AVIFILE32 = "AVIFIL32";
        private int _pfile = 0;
        private IntPtr _ps = new IntPtr(0);
        private IntPtr _psCompressed = new IntPtr(0);
        private UInt32 _frameRate = 0;
        private int _count = 0;
        private UInt32 _width = 0;
        private UInt32 _stride = 0;
        private UInt32 _height = 0;
        //avi标识
        private UInt32 _fccType = 1935960438; // vids
        private UInt32 _fccHandler = 808810089;// IV50

        private Bitmap _bmp;

        [DllImport(AVIFILE32)]
        private static extern void AVIFileInit();

        [DllImport(AVIFILE32)]
        private static extern int AVIFileOpenW(ref int ptr_pfile, [MarshalAs(UnmanagedType.LPWStr)]string fileName, int flags, int dummy);

        [DllImport(AVIFILE32)]
        private static extern int AVIFileCreateStream(int ptr_pfile, out IntPtr ptr_ptr_avi, ref AVISTREAMINFOW ptr_streaminfo);
        [DllImport(AVIFILE32)]
        private static extern int AVIMakeCompressedStream(out IntPtr ppsCompressed, IntPtr aviStream, ref AVICOMPRESSOPTIONS ao, int dummy);

        [DllImport(AVIFILE32)]
        private static extern int AVIStreamSetFormat(IntPtr aviStream, Int32 lPos, ref BITMAPINFOHEADER lpFormat, Int32 cbFormat);

        [DllImport(AVIFILE32)]
        unsafe private static extern int AVISaveOptions(int hwnd, UInt32 flags,int nStreams, IntPtr* ptr_ptr_avi, AVICOMPRESSOPTIONS** ao);

        [DllImport(AVIFILE32)]
        private static extern int AVIStreamWrite(IntPtr aviStream, Int32 lStart,Int32 lSamples, IntPtr lpBuffer, Int32 cbBuffer, Int32 dwFlags, Int32 dummy1, Int32 dummy2);

        [DllImport(AVIFILE32)]
        private static extern int AVIStreamRelease(IntPtr aviStream);

        [DllImport(AVIFILE32)]
        private static extern int AVIFileRelease(int pfile);

        [DllImport(AVIFILE32)]
        private static extern void AVIFileExit();

        [StructLayout(LayoutKind.Sequential, Pack = 1)]
            private struct AVISTREAMINFOW
        {
            public UInt32 fccType;