Questions about QuickTime tags

[Fulco]

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]

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.

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.

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

[Fulco]

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.

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

Thanks for clarification.

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]

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

[Fulco]

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]

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

[Fulco]

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]

if only ContentCreateDate is written, only ItemList:ContentCreateDate is added.

Yes.

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