Efficient way to write a very large number of TIFF pages using libtiff.net

Question

I use the following code to write a sequence of 16-bit grayscale images (an empty array for the purpose of this question) for multi-page TIFF:

int numberOfPages = 1000;
int width = 256;
int height = 256;
string fileName = "test.tif";

ushort[] image = new ushort[width * height];
byte[] buffer = new byte[width * height * sizeof(ushort)];

Stopwatch stopWatch = new Stopwatch();

using (Tiff output = Tiff.Open(fileName, "w"))
{
    if (output == null)
    {
        return;
    }
    stopWatch.Start();
    for (int i = 0; i < numberOfPages; i++)
    {
        Buffer.BlockCopy(image, 0, buffer, 0, buffer.Length);

        output.SetField(TiffTag.IMAGEWIDTH, width);
        output.SetField(TiffTag.IMAGELENGTH, height);
        output.SetField(TiffTag.SAMPLESPERPIXEL, 1);
        output.SetField(TiffTag.BITSPERSAMPLE, 16);
        output.SetField(TiffTag.ORIENTATION, Orientation.TOPLEFT);
        output.SetField(TiffTag.XRESOLUTION, 96);
        output.SetField(TiffTag.YRESOLUTION, 96);
        output.SetField(TiffTag.PLANARCONFIG, PlanarConfig.CONTIG);
        output.SetField(TiffTag.PHOTOMETRIC, Photometric.MINISBLACK);
        output.SetField(TiffTag.COMPRESSION, Compression.NONE);
        output.SetField(TiffTag.FILLORDER, FillOrder.MSB2LSB);
        output.SetField(TiffTag.SUBFILETYPE, FileType.PAGE);
        output.SetField(TiffTag.PAGENUMBER, i + 1, numberOfPages);

        output.WriteEncodedStrip(0, buffer, buffer.Length);

        output.WriteDirectory();
    }
    stopWatch.Stop();
}

Debug.WriteLine(stopWatch.ElapsedMilliseconds);

It works fine up to several hundred pages, but it seems that the runtime does not scale linearly with the increase in the number of pages. For instance:

1000 pages --- 3130 ms

2000 pages --- 11778 ms

3000 pages --- 25830 ms

I also tried using add mode in a loop, but got similar results.

Am I doing this wrong or should I expect such an overhead?

Answer 1

Visual Studio (Analyze → Performance Profiler) , :

5000 91% , TIFF. , , . , , WriteDirectory .

WriteDirectory . , . TIFF, .

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