Author Topic: Error: Multiple 'mdat' blocks!  (Read 205 times)


  • Newbie
  • *
  • Posts: 1
Error: Multiple 'mdat' blocks!
« on: January 25, 2019, 06:54:33 PM »

I am adding metadata to a lot of mov files on a Linux server and about 10% of them (ca. 80 files) failed with this error: Error: Multiple 'mdat' blocks! Can only edit existing tags

I installed the newer version 11.26 and I'm still getting the error.

My command is:
eval /opt/Image-ExifTool-11.26/exiftool -overwrite_original -g -title="" -description="Something\ here" -creator="Institution\ Name"

And I get:
Error: Multiple 'mdat' blocks!  Can only edit existing tags -
    0 image files updated
    1 files weren't updated due to errors

I will email you a link to the mov file as it's too large for the forum.

Thank you for any assistance!


Phil Harvey

  • ExifTool Author
  • Administrator
  • ExifTool Freak
  • *****
  • Posts: 14896
    • ExifTool Home Page
Re: Error: Multiple 'mdat' blocks!
« Reply #1 on: January 26, 2019, 07:10:36 AM »
Right.  Currently that's a limitation of ExifTool.  The video writing ability is somewhat limited, and videos written with multiples mdat chunks are an extra complication that needs special programming.  It is on my list of things to do when I get a chance.

- Phil
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).