Author Topic: Questions about QuickTime tags  (Read 671 times)

Fulco

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Questions about QuickTime tags
« on: May 08, 2019, 08:29:13 AM »
I have a few questions about the last two versions of Exiftool:

QuickTime Keys Tags can no longer be changed, but the values ​​are deleted in Exiftool 11.39 and 11.40. In the previous versions this was not yet the case. Is this a bug?

I only can newly create QuickTime User Data Tags and ItemList Tags. Is this not possible for QuickTime Keys Tags?

Tag ID of ContentCreateDate is read in reverse as yad© instead of ©day. I think this value is therefore not recognized for example in the Mac Photos-application. Is that right?

Regards,
Fulco

Phil Harvey

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Re: Questions about QuickTime tags
« Reply #1 on: May 08, 2019, 09:08:17 AM »
Hi Fulco,

Thanks for the feedback.

QuickTime Keys Tags can no longer be changed, but the values ​​are deleted in Exiftool 11.39 and 11.40. In the previous versions this was not yet the case. Is this a bug?

This was a bug in 11.39, but should be fixed in 11.40.

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I only can newly create QuickTime User Data Tags and ItemList Tags. Is this not possible for QuickTime Keys Tags?

Not yet.  Note that Adobe Bridge won't create these either.

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Tag ID of ContentCreateDate is read in reverse as yad© instead of ©day. I think this value is therefore not recognized for example in the Mac Photos-application. Is that right?

I don't understand.  Is this a problem when reading, or writing?  On what platform?  Can you provide a sample and a command so I can reproduce this?  (my email is philharvey66 at gmail.com)

- 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 ($).

Fulco

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Re: Questions about QuickTime tags
« Reply #2 on: May 08, 2019, 12:40:40 PM »
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This was a bug in 11.39, but should be fixed in 11.40.

Stupid me. I should have installed version 11.40 before commenting on this. Exiftool 11.40 solved the problem.

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Not yet.  Note that Adobe Bridge won't create these either.

Thanks for clarification.

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I don't understand.  Is this a problem when reading, or writing?  On what platform?  Can you provide a sample and a command so I can reproduce this?  (my email is philharvey66 at gmail.com)

I mean reading the tag ID and its value. I can read this with "QT Edit" (from Digital Rebellion, see attachment). It displays the ContentCreateDate with the Tag ID ""yad©". In the Exiftool documentation I can't find the ID "yad©" in the tables of Quicktime Tags. EditReady (from Divergent Media) and Photos do not recognize this tag at all, while MediaInfo identifies this tag as "Recorded date".

Regards,
Fulco

Phil Harvey

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Re: Questions about QuickTime tags
« Reply #3 on: May 08, 2019, 12:46:10 PM »
Hi Fulco,

I can read this with "QT Edit" (from Digital Rebellion, see attachment). It displays the ContentCreateDate with the Tag ID ""yad©".

Could it be that QT Edit is showing this in the wrong byte order?  ExifTool reads this as '\xa9day' (ie. '©day') when I run a test here:

Code: [Select]
> exiftool tmp/QuickTime.mov -contentcreatedate=now
    1 image files updated

> exiftool tmp/QuickTime.mov -v3 | grep -A 1 Content
  | | | | ContentCreateDate = 2019-05-08T12:45:03-0400
  | | | | - Tag '\xa9day', Type='data', Flags=0x1 (24 bytes):

- 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 ($).

Fulco

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Re: Questions about QuickTime tags
« Reply #4 on: May 10, 2019, 04:16:14 AM »
Hello Phil,

Could it be that QT Edit is showing this in the wrong byte order? 

I don't know. The tag ID of ContentCreateDate from an original iPhone video is recognized as "©day" in QT Edit and EditReady. With ffprobe as "date". Exiftool can change the value of "©day", but then also add the tag with ID "yad©" according to QT Edit. If the tag "©day" is added with exiftool without it already being present in the video then this date will not be recognized by the applications I mentioned and the Photo app. I don't know where the problem is. I will work around it.

Regards,
Fulco

Phil Harvey

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Re: Questions about QuickTime tags
« Reply #5 on: May 10, 2019, 07:04:24 AM »
Hi Fulco,

What is the output of this command before and after you modify the file?:

exiftool -contentcreatedate -G1 FILE

If, for example, you only have UserData:ContentCreateDate before you write the file, then ExifTool will then add ItemList:ContentCreateDate if you write this tag without specifying a group name.  (See the second paragraph here for an explanation.)  In this case, you could try writing it like this:

exiftool -userdata:contentcreatedate="some value" FILE

- 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 ($).

Fulco

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Re: Questions about QuickTime tags
« Reply #6 on: May 13, 2019, 10:06:14 AM »
If, for example, you only have UserData:ContentCreateDate before you write the file, then ExifTool will then add ItemList:ContentCreateDate if you write this tag without specifying a group name.  (See the second paragraph here for an explanation.)  In this case, you could try writing it like this:

exiftool -userdata:contentcreatedate="some value" FILE

That is very instructive. Indeed, if only ContentCreateDate is written, only ItemList:ContentCreateDate is added. If UserData:ContentCreateDate is written then both tags are added. I was not aware of that. Now the tag ID of UserData:ContentCreateDate in QT Edit and EditReady is displayed as "©day". I think the tag ID of ItemList:ContentCreateDate is read by QT Edit in the wrong byte order as "yad©".

Thank you for the explanation!

Phil Harvey

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Re: Questions about QuickTime tags
« Reply #7 on: May 13, 2019, 10:34:38 AM »
if only ContentCreateDate is written, only ItemList:ContentCreateDate is added.

Yes.

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If UserData:ContentCreateDate is written then both tags are added.

No.  Only UserData:ContentCreateDate is added.

But if you don't specify a location, then ItemList:ContentCreateDate will be written (and created if it didn't already exist), and UserData:ContentCreateDate will be updated if it already existed.

So it seems you need to write the UserData tags to be compatible with your QT Edit software.

- 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 ($).