Reading EXIF without loading picture? (GflAX.dll)
Posted: Wed May 06, 2009 7:16 pm
Hello,
First I would like thank you for your work and really good library to manage the images. I mean GflAX DLL. Currently I'm using the version GflAX DLL 2.60- GFL 2.82 in a C# project.
In the feature list of library you wrote: "EXIF reading (with or without loading picture)". That's what I need - reading EXIF without loading picture. But I can't get it done. It seems like the picture will be loaded completely.
What is my goal:
I have a lot of photos in different formats: JPEG, TIFF, NEF, CR2, PNG etc. I need to scan them all very quick and read _only_ EXIF meta data (EXIFDateTaken, ExifDTDigitized and lastly DateTime) from each file, without to load the picture in the memory.
What I do now:
I'm almost happy with the solution. It is fast. When I understand it correctly, with this method the library access only embedded thumbnail of the picture. But I have nevertheless the problems with the pictures without embedded thumbnail. In that case it seems like library create the thumbnail by itself.
When I use the LoadBitmap() instead of LoadThumbnails() it takes much longer. I've been looking for a method like ReadExifTag( String Filename, int Tag ) or bytes[] ReadExifData(String Filename), but such methods doesn't exist in the dll.
Is it the right way to do "reading without loading picture"? How can I access only EXIF metadata?
Can you explain me, how can I to do it right using your library - reading EXIF without loading picture?
I looking forward to get your response.
Thank you in advance.
P.S. What the library really do, when I use LoadThumbnails(SrcFile, 0, 0)?
First I would like thank you for your work and really good library to manage the images. I mean GflAX DLL. Currently I'm using the version GflAX DLL 2.60- GFL 2.82 in a C# project.
In the feature list of library you wrote: "EXIF reading (with or without loading picture)". That's what I need - reading EXIF without loading picture. But I can't get it done. It seems like the picture will be loaded completely.
What is my goal:
I have a lot of photos in different formats: JPEG, TIFF, NEF, CR2, PNG etc. I need to scan them all very quick and read _only_ EXIF meta data (EXIFDateTaken, ExifDTDigitized and lastly DateTime) from each file, without to load the picture in the memory.
What I do now:
Code: Select all
GflAx.GflAxClass gl = new GflAx.GflAxClass();
...
gl.UseEmbeddedThumbnail = 1;
gl.LoadThumbnail(SrcFile, 0, 0);
String tmpDate = gl.EXIFDateTaken;
...
gl.FreeBitmap();
When I use the LoadBitmap() instead of LoadThumbnails() it takes much longer. I've been looking for a method like ReadExifTag( String Filename, int Tag ) or bytes[] ReadExifData(String Filename), but such methods doesn't exist in the dll.
Is it the right way to do "reading without loading picture"? How can I access only EXIF metadata?
Can you explain me, how can I to do it right using your library - reading EXIF without loading picture?
I looking forward to get your response.
Thank you in advance.
P.S. What the library really do, when I use LoadThumbnails(SrcFile, 0, 0)?
