Re: [GM-help] Problem with MingW in Image::read

[Vishakh T. <vis...@gm...>]

Hi Bob
Actually I am reading from a PNG file at the moment. The thing is that when
I use VC++ with ImageMagick the same code works perfectly, but it fails
completely when we try with GraphicsMagick compiled with MingW.
It is the same test code.
I have also tried using ffmpeg. But it has a memory corruption when we use
it under windows, It crashes. at random.


On 5/2/06, Bob Friesenhahn <bfr...@si...> wrote:
>
> On Tue, 2 May 2006, Vishakh Thomas wrote:
> >     printf(".%d", i);
> >     Blob blob1(picture, 480*336*8);
> >     printf("..%d", i);
> >
> >     img1.read(blob1, geo);
> >     printf("...%d", i);
> >     imgList.push_back(img1);
> >     printf("....%d", i);
> >     imgList.push_back(img1);
> >   }
> >   writeImages(imgList.begin(), imgList.end(), "c:/flom-test.mpeg");
> >
> > It crashes at the line: img1.read(blob1, geo);
> >
> > I have also tried img1.read(filename); But that also crashes.
>
> I suspect that "crashes" in this case really means that read() threw a
> C++ exception and you did not include any try/catch block so the C++
> run-time invoked unhandled() which in turn invokes abort().  The
> exception is likely occuring since the format auto-detect code did not
> recognize the data.
>
> The approach you are using is intended for formatted data (like a
> file) rather than raw raster data.  You will likely encounter more
> success if you use a different read() method.  For example
>
>   img1.read(480,336,"RGB",CharPixel,(const void *)picture);
>
> This example assumes that the data occurs in "RGB" format but maybe
> the data is in some other order (e.g. "BGR").
>
> With this approach, you don't need to use the Blob class at all.  You
> should definitely add C++ exception handling so that if an exception
> is thrown, you can catch it and print its what() string.
>
> > The main problem is that I have an OpenGL project that loads a series o=
f
> > images stored in a proprietary file using a QT class. This class QImage
> can
> > return the raw RGB format of each image which i need to convert into an
> MPEG
> > file. Any inputs on how I can do it?
>
> GraphicsMagick is not the best tool for creating MPEG since it buffers
> all the frames in memory and then needs to write a huge number of
> temporary files as input to 'mpeg2encode'.  Using ffmpeg (or a library
> for ffmpeg) would be much more effective.
>
> Bob
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> Bob Friesenhahn
> bfr...@si..., http://www.simplesystems.org/users/bfriesen=
/
> GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
>



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VPT