/// <summary>
    /// AVC1 formatted H264 bitstream
    /// </summary>
    /// <param name="streamInfo"></param>
    /// <returns></returns>
    public static AMMediaType H264_AVC1(InputstreamInfo streamInfo)
    {
      H264CodecData codecData = null;
      Mpeg2VideoInfo vi = new Mpeg2VideoInfo();
      byte[] extraData = new byte[0];
      int width = (int)streamInfo.Width;
      int height = (int)streamInfo.Height;

      if (streamInfo.ExtraData.Length > 0)
      {
        codecData = new H264CodecData(streamInfo.ExtraData);

        SPSUnit spsUnit = new SPSUnit(codecData.SPS);
        width = spsUnit.Width();
        height = spsUnit.Height();
      }

      vi.hdr.SrcRect.right = width;
      vi.hdr.SrcRect.bottom = height;
      vi.hdr.TargetRect.right = width;
      vi.hdr.TargetRect.bottom = height;

      int hcf = HCF(width, height);
      vi.hdr.PictAspectRatioX = width / hcf;
      vi.hdr.PictAspectRatioY = height / hcf;

      vi.hdr.BmiHeader.Width = width;
      vi.hdr.BmiHeader.Height = height;

      vi.hdr.BmiHeader.Planes = 1;
      vi.hdr.BmiHeader.Compression = FOURCC_AVC1;
      vi.hdr.BmiHeader.BitCount = 24;

      if (codecData != null)
      {
        vi.dwProfile = (uint)codecData.Profile;
        vi.dwLevel = (uint)codecData.Level;
        vi.dwFlags = (uint)codecData.NALSizeMinusOne + 1;

        extraData = NaluParser.CreateAVC1ParameterSet(codecData.SPS, codecData.PPS, 2);
      }
      else
      {
        // Example: avc1.4D401F -> Main Level 3.1
        // Profile     Value
        // Baseline    42E0
        // Main        4D40
        // High        6400
        // Extended    58A0

        // Level       Hex Value
        // 3.0         1E
        // 3.1         1F
        // 4.1         29
        // 5.1         33
        string codecInfo = streamInfo.CodecInternalName.Split('.').Last();
        if (codecInfo.Length == 6)
        {
          int codecNum;
          if (int.TryParse(codecInfo.Substring(0, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out codecNum))
            vi.dwProfile = (uint)codecNum;
          if (int.TryParse(codecInfo.Substring(4, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out codecNum))
            vi.dwLevel = (uint)codecNum;
        }
      }

      vi.cbSequenceHeader = (uint)extraData.Length;

      AMMediaType amt = new AMMediaType();
      amt.majorType = MediaType.Video;
      amt.subType = MEDIASUBTYPE_AVC1;
      amt.temporalCompression = true;
      amt.fixedSizeSamples = false;
      amt.sampleSize = 1;
      SetFormat(vi, extraData, amt);
      return amt;
    }
 /// <summary>
 /// Sets AMMediaType format data with Mpeg2VideoInfo and optional extra data.
 /// </summary>
 /// <param name="vi"></param>
 /// <param name="extraData"></param>
 /// <param name="amt"></param>
 static void SetFormat(Mpeg2VideoInfo vi, byte[] extraData, AMMediaType amt)
 {
   int cb = Marshal.SizeOf(vi);
   int add = extraData == null || extraData.Length < 4 ? 0 : extraData.Length - 4;
   IntPtr ptr = Marshal.AllocCoTaskMem(cb + add);
   try
   {
     Marshal.StructureToPtr(vi, ptr, false);
     if (extraData != null)
       Marshal.Copy(extraData, 0, ptr + cb - 4, extraData.Length);
     amt.SetFormat(ptr, cb + add);
     amt.formatType = FormatType.Mpeg2Video;
   }
   finally
   {
     Marshal.FreeCoTaskMem(ptr);
   }
 }