Hi all.

I'm trying to create a directshow graph to playback a video composed of 8bit grayscale bitmaps. (using directshow.net.)

I'm using a source filter and the vmr9 renderer.

The source filter's output pin is defined using the following code :

            bmi.Size = Marshal.SizeOf(typeof(BitmapInfoHeader));
            bmi.Width = width;
            bmi.Height = height;;
            bmi.Planes = 1;
            bmi.BitCount = (short)bitcount;
            bmi.Compression = 0;
            bmi.ImageSize = Math.Abs(bmi.Height) * bmi.Width * bmi.BitCount / 8;
            bmi.ClrUsed = bmi.BitCount <= 8 ? 256 : 0;
            bmi.ClrImportant = 0;

            //bmi.XPelsPerMeter = 0;
            //bmi.YPelsPerMeter = 0;
            bool isGrayScale = bmi.BitCount <= 8 ? true : false;
            int formatSize = Marshal.SizeOf(typeof(BitmapInfoHeader));
            if (isGrayScale == true)
            {
                MessageWriter.Log.WriteTrace("Playback is grayscale.");
                /// Color table holds an array of 256 RGBQAD values
                /// Those are relevant only for grayscale bitmaps
                formatSize += Marshal.SizeOf(typeof(RGBQUAD)) * bmi.ClrUsed;
            }
            IntPtr ptr = Marshal.AllocHGlobal(formatSize);
            Marshal.StructureToPtr(bmi, ptr, false);
            if (isGrayScale == true)
            {
                /// Adjust the pointer to the beginning of the 
                /// ColorTable address and create the grayscale color table
                IntPtr ptrNext = (IntPtr)((int)ptr + Marshal.SizeOf(typeof(BitmapInfoHeader)));

                for (int i = 0; i < bmi.ClrUsed; i++)
                {
                    RGBQUAD rgbCell = new RGBQUAD();
                    rgbCell.rgbBlue = rgbCell.rgbGreen = rgbCell.rgbRed = (byte)i;
                    rgbCell.rgbReserved = 0;
                    Marshal.StructureToPtr(rgbCell, ptrNext, false);
                    ptrNext = (IntPtr)((int)ptrNext + Marshal.SizeOf(typeof(RGBQUAD)));
                }
            }

This causes Renderstream to return "No combination of intermediate filters could be found to make the connection."

Please help!

Thanks.