DO11: Comments/User Description META in .mp4

Hello all,

I have encountered a problem whilst using the META editor to store information about a .mp4 file.

Using the Dopus META editor I decided to store some descriptive information in the 'comments' field, which can then be displayed by enabling the 'User Description' column in the lister. I did this to quite a number of .mp4 files successfully and my comments are indeed displayed in the User Description column as planned. As a test (so you can see it working) I have taken a screengrab of some information I've added to a test .mp4 file:

As you can see there is Comment META data "Video Test Card" and this is being displayed using the User Description column. There is also some test tags and a rating. This is repeatable for any .mp4 file and initially appears to work without problem.

THE PROBLEM

The problems start if you try to copy a file. When I try this I find that the comment META is not copied across in the new file. The tag and rating META copy across fine. Out of interest I decided to check the properties for the test file above. I then find that the comments field is blank, despite it being populated with data in the Dopus META editor. That's probably why the data doesn't get copied across to a new file.
I also notice that there are many more properties available in the properties dialogue box than are made available for editing in the Dopus META editor. Here is a screen grab of the properties dialogue box:

My questions are:

1: Why is the system properties dialogue box showing blank data for the comments field when the Dopus META editor shows it populated with data? And Is this the reason that the comments field data is not copied across to a new file?

2: Why does the Dopus META editor not display options for editing some of the other available fields that are shown in the properties dialogue box (e.g. title)?

I should also add that I tried a similar task with a .jpg file and the comments META data that I enter via the Dopus META editor is seen by the properties dialogue box and does get copied across to a new file. So the problem I am reporting is certain to specific type(s) of file.

Thanks in advance!

PS: I have just noticed, as I was about to submit my post, that the Dopus META editor is showing the User Description field as "Comments" where as the Properties dialogue box shows a "Comment" field. So they are named very slightly differently!
I checked a .jpg file and the Dopus META editor correctly labels the field "Comment", the same as the Properties dialogue box. I think this is relevant.

Brian

Does that happen only with MP4 files? Just in case, in -> preferences -> file operations you have to have the
"copy metadata" option enabled, & of course an NTSF drive.

Thanks for the response abr

I have just checked my preferences and you were correct about the file operations settings - the option to copy metadata was not enabled. I have enabled it and now the comments data is copied across.

But I still think there is still a problem to be investigated here. Here are my new comments/questions:

1:
Why does the META data copy across fine for other filetypes (such as .jpg) regardless of the copy metadata option? Also, why is the Tags and Rating META data copied across fine for the .mp4 filetype but Comment META is not until I enable the copy metadata option?
2:
The copy META data option does not explain why the properties dialogue box fails to show the information that was entered for comments and I think this is due to a naming error between the data that we enter in the Dopus META editor ("Comment") and the data that the properties dialogue attempts to display ("Comments").
3:
There is also still the issue that the properties dialogue box shows many more information fields that are available but these aren't made available for editing in the Dopus META editor.

Thanks once again!

Brian

Comments are stored differently for different filetypes.

With JPEG files, they can be stored within the JPG itself, inside the EXIF data.

With some file formats, there either isn't any way to store a comment in the main file data itself (e.g. a plain text file), or there is but both Opus and Windows (and any installed shell extensions) are unaware of how to do it. In those cases, the comment will be stored using NTFS streams, which have to be copied explicitly (and will also be lost if you e.g. copy the file to a FAT drive that can't store alternate data streams). (Unless the option to use the old-style descript.ion files is switched on.)

The Properties dialog complicates things further because it will only show things that Windows itself understands how to read.

Thanks Leo - I understand the complications you've described for file types that are not designed to accommodate the data within the file itself. I had not realised this was the case for .mp4 filetypes.

Is it possible that Windows properties would understand the comments field that Dopus has written if the nomenclature was identical between them? Windows properties is expecting to find a field called "Comments" but the Dopus META editor inserts a "Comment" field. It would seem that Windows Properties is the more correct here, since .jpg files, which have support for META data built into the filetype, uses "Comments" fields not "Comment" fields.

Thanks for the support - it sounds like this problem is mostly just an issue with using META data on .mp4 files specifically, rather than being an actual problem with Dopus itself.

Brian

The exact label used for the field shouldn't matter. It'll be a completely different word in other languages and is just part of the user interface, not something like a database key.

I'm not sure about what the details of MP4 and what Explorer supports, sorry.