overwriting orientation tag

[alexbigkid]

Hi Phil,

I'm using your exif tool perl API to update orientation tags after rotating the images.
It looks like most of the jpegs I'm rotating contain 2 Orientation tags: 'Orientation' and 'Orientation (1)'
If I out put the tags in XML format I get following
<IFD0:Orientation>Rotate 90 CW</IFD0:Orientation>
<IFD1:Orientation>Rotate 90 CW</IFD1:Orientation>

updating the 'Orientation' works just fine, but updating the 'Orientation (1)' never works. Any ideas?
I used following code:

    my @update = ('ExifImageWidth', 'ExifImageHeight', 'Orientation', 'ImageDescription');
    my $exif_tool;
    my $dst_exif = 0;

    # create the instance of exif tool
    $exif_tool = new Image::ExifTool;

    $exif_tool->Options(PrintConv => 0);
    $dst_exif = $exif_tool->ImageInfo($rot_img, \@update);

    # update width and height if they have to be swapped
    if($org_orientation > 4) # all swapped are 5, 6, 7 and 8
    {
      # update width and height
      $exif_tool->SetNewValue('ExifImageWidth',  ${$dst_exif}{'ExifImageHeight'}) if(defined(${$dst_exif}{'ExifImageWidth'}));
      $exif_tool->SetNewValue('ExifImageHeight', ${$dst_exif}{'ExifImageWidth'}) if(defined(${$dst_exif}{'ExifImageHeight'}));
    }

    $exif_tool->SetNewValue('Orientation' => 1, Type => 'ValueConv') if(defined(${$dst_exif}{'Orientation'}));
    if(defined(${$dst_exif}{'Orientation (1)'}))
    {
      $exif_tool->SetNewValue('Orientation (1)' => 1, Type => 'ValueConv') if(defined(${$dst_exif}{'Orientation (1)'}));
      print STDOUT "abk_test !!!\n";
    }
    ${$dst_exif}{'ImageDescription'} = (defined(${$dst_exif}{'ImageDescription'})) ? ${$dst_exif}{'ImageDescription'} . "\n" : "";
    $exif_tool->SetNewValue('ImageDescription', ${$dst_exif}{'ImageDescription'} . "rotated from orientation $org_orientation");

    # write new values to the rotated image
    $exif_tool->WriteInfo($rot_img);

[Phil Harvey]

Try this:

$exifTool->SetNewValue('IFD1:Orientation' => 1, Type => 'ValueConv');

- Phil

[wildgoose]

Phil, first of all I want to say thank you for creating the EXIF tool. I've been using it in my perl script for a few years now and it's quite nice!

I have the same need as OP, but a slightly different question.

Is there a way to reset the orientation flag while minimizing the binary changes on the file? My perl script essentially does:

Code Select Expand


my $exifTool = new Image::ExifTool;
my $info = $exifTool->ImageInfo($filename);
# do some validation, then   
$exifTool->SetNewValue('Orientation#' => $newval, EditOnly => 1);
$exifTool->WriteInfo($filename, $newname);


However, the output file's size is different from the original file:


11/23/2007  15:04       3,214,560  ______N_______  20071123_140406_6081_sd500.JPG
4/28/2011  10:32       3,211,304  ______N_______  20071123_140406_6081_sd500_x.jpg


My main concern is to make sure I don't corrupt or delete any information from the exif file. I used exiftool to output exif info on old and new file, the only differences that I see are the few attributes relates to ThumbnailImage


20071123_140406_6081_sd500.JPG:           ThumbnailImage: SCALAR(0x6012504)
20071123_140406_6081_sd500.JPG:  ThumbnailImageValidArea: 0 0 0 0
20071123_140406_6081_sd500.JPG:          ThumbnailLength: 5141
20071123_140406_6081_sd500.JPG:          ThumbnailOffset: 5120

20071123_140406_6081_sd500.JPG.new:           ThumbnailImage: SCALAR(0x5e3248c)
20071123_140406_6081_sd500.JPG.new:  ThumbnailImageValidArea: 0 0 0 0
20071123_140406_6081_sd500.JPG.new:          ThumbnailLength: 5141
20071123_140406_6081_sd500.JPG.new:          ThumbnailOffset: 2356


I used picasa and looked at the images, the thumbnails are there for both images and looked the same. So I am not sure what the differences in filesize are..

Ideally, I'd like to see just one or two byte changes when I diff the file. This way I can confidently delete the original file.

If I change the orientation flag on the output file again, then new output is the same size, and differs by only one byte:


>fc /b 20071123_140406_6081_sd500_x.jpg 20071123_140406_6081_sd500_x.jpg.new
Comparing files 20071123_140406_6081_sd500_x.jpg and 20071123_140406_6081_SD500_X.JPG.NEW
00000036: 01 06


Is there a way to get it to change just one byte on the first go around?

Thanks!

[Phil Harvey]

FAQ number 13 explains this.  There is no way to change this when writing with ExifTool.

- Phil