How to convert TIFF to JPEG?

Question

I am trying to convert a TIFF file to JPEG using FreeImage.

The problem is that FreeIamge.SaveToStream doesn't actually do anything. Even after the call, stream has a Length, Capacity and Position of 0.

This is my code:

using (var stream = new MemoryStream())
{
    var image = FreeImage.LoadEx(fileName);
    FreeImage.SaveToStream(image, stream, FREE_IMAGE_FORMAT.FIF_JPEG,
                           FREE_IMAGE_SAVE_FLAGS.JPEG_QUALITYSUPERB);

    // stream.Length, stream.Capacity & stream.Position are all 0 here
}

What am I doing wrong?

Out of curiosity, why using the `MemoryStream` at all? Why not just call `SaveToStream` directly on the `FileStream`? — vcsjones, Sep 22 '14 at 12:34
@TheodorosChatzigiannakis: That doesn't help. [`MemoryStream.WriteTo`](http://msdn.microsoft.com/en-us/library/system.io.memorystream.writeto(v=vs.110).aspx) writes the *entire* contents of the `MemoryStream` to the other stream. This is documented. Furthermore, I checked: The `MemoryStream` has a length, capacity and position of 0. — Daniel Hilgarth, Sep 22 '14 at 12:46
@vcsjones: Because this is a boiled down example code from my real code in which I need this step in between. — Daniel Hilgarth, Sep 22 '14 at 12:47
So the question is why `FreeImage.SaveToStream` does not actually do that. — Lasse V. Karlsen, Sep 22 '14 at 12:47
And whoever downvoted that question should leave a comment, so I can improve it. — Daniel Hilgarth, Sep 22 '14 at 12:47
@LasseV.Karlsen: Simplified the question, thanks for the hint. — Daniel Hilgarth, Sep 22 '14 at 12:51

score 1 · Accepted Answer · answered Sep 29 '14 at 08:05

1

The problem was the input - a 16 bit image created by another image library. It looks like FreeImage has some problems with 16 bit images as GDI+ could read it without problems. I switched the input to a 24 bit image and the code in my question started working.

answered Sep 29 '14 at 08:05

Daniel Hilgarth

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Sigh... the joys of libraries that are not using exception handling. [Seems that `SaveToStream` returns a `bool` for success/failure](http://freeimage.sourceforge.net/fnet/html/4A01CFCD.htm). – Uwe Keim Sep 29 '14 at 08:16
"GDI+ could read it without problems" -- GDI+ could read a 16-bit TIFF? My experience with PNG files (I just ran into this) is that System.Drawing.Image (.NET wrapper for GDI+) downconverts 16-bit to 8-bit and multiplies single-channel to RGBA, but I haven't tried TIFF yet. – Mike C Apr 17 '15 at 01:23

How to convert TIFF to JPEG?

1 Answers1