/// <summary>Add an existing wave audio stream to the file</summary>
        /// <param name="waveData">The new stream's data</param>
        /// <param name="streamInfo">Header info for the new stream</param>
        /// <param name="streamFormat">The new stream' format info</param>
        /// <param name="streamLength">Length of the new stream</param>
        public void AddAudioStream(IntPtr waveData, Avi.AVISTREAMINFO streamInfo, Avi.PCMWAVEFORMAT streamFormat, int streamLength)
        {
            IntPtr aviStream;
            int    result = Avi.AVIFileCreateStream(aviFile, out aviStream, ref streamInfo);

            if (result != 0)
            {
                throw new Exception("Exception in AVIFileCreateStream: " + result.ToString());
            }

            result = Avi.AVIStreamSetFormat(aviStream, 0, ref streamFormat, Marshal.SizeOf(streamFormat));
            if (result != 0)
            {
                throw new Exception("Exception in AVIStreamSetFormat: " + result.ToString());
            }

            result = Avi.AVIStreamWrite(aviStream, 0, streamLength, waveData, streamLength, Avi.AVIIF_KEYFRAME, 0, 0);
            if (result != 0)
            {
                throw new Exception("Exception in AVIStreamWrite: " + result.ToString());
            }

            result = Avi.AVIStreamRelease(aviStream);
            if (result != 0)
            {
                throw new Exception("Exception in AVIStreamRelease: " + result.ToString());
            }
        }
        /// <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>Add an existing wave audio stream to the file</summary>
        /// <param name="newStream">The stream to add</param>
        /// <param name="startAtFrameIndex">
        /// The index of the video frame at which the sound is going to start.
        /// '0' inserts the sound at the beginning of the video.
        /// </param>
        public void AddAudioStream(AudioStream newStream, int startAtFrameIndex)
        {
            Avi.AVISTREAMINFO streamInfo   = new Avi.AVISTREAMINFO();
            Avi.PCMWAVEFORMAT streamFormat = new Avi.PCMWAVEFORMAT();
            int streamLength = 0;

            IntPtr rawData  = newStream.GetStreamData(ref streamInfo, ref streamFormat, ref streamLength);
            IntPtr waveData = rawData;

            if (startAtFrameIndex > 0)
            {
                //not supported
                //streamInfo.dwStart = startAtFrameIndex;

                double framesPerSecond  = GetVideoStream().FrameRate;
                double samplesPerSecond = newStream.CountSamplesPerSecond;
                double startAtSecond    = startAtFrameIndex / framesPerSecond;
                int    startAtSample    = (int)(samplesPerSecond * startAtSecond);

                waveData = InsertSilence(startAtSample - 1, waveData, streamLength, ref streamInfo);
            }

            IntPtr aviStream;
            int    result = Avi.AVIFileCreateStream(aviFile, out aviStream, ref streamInfo);

            if (result != 0)
            {
                throw new Exception("Exception in AVIFileCreateStream: " + result.ToString());
            }

            result = Avi.AVIStreamSetFormat(aviStream, 0, ref streamFormat, Marshal.SizeOf(streamFormat));
            if (result != 0)
            {
                throw new Exception("Exception in AVIStreamSetFormat: " + result.ToString());
            }

            result = Avi.AVIStreamWrite(aviStream, 0, streamLength, waveData, streamLength, Avi.AVIIF_KEYFRAME, 0, 0);
            if (result != 0)
            {
                throw new Exception("Exception in AVIStreamWrite: " + result.ToString());
            }

            result = Avi.AVIStreamRelease(aviStream);
            if (result != 0)
            {
                throw new Exception("Exception in AVIStreamRelease: " + result.ToString());
            }

            Marshal.FreeHGlobal(waveData);
        }