File dates come in two varieties:
If this is news to you, you probably want to read the “File Date Primer” before you go on, as this will avoid a lot of confusion & frustration.
Let’s now turn our attention to embedded dates for image & movie file formats:
First, you need to realize that pretty much every image & movie file format has its own way of embedding date information and not all the dates mean the same thing. Then you need to realize than in practice, many programs do not handle those dates correctly or uniformly.
For image file formats, the Japanese EXIF standard, which exists in several versions is the commonly used standard. Almost all JPEG files that come straight off a digital camera will have this meta-data information embedded in them. Some scanners will also include EXIF information in scanned files, but many do not. The same dates are also embedded in a variety of “RAW” file formats by all major camera manufacturers.
The EXIF
standard has two dates, called “timestamps” that are of interest to us: DateTimeOriginal
&
DateTimeDigitized
.
DateTimeOriginal
is the date & time that a photo was taken. DateTimeDigitized
is the date & time that a picture
was scanned or otherwise digitized. In theory, scanners should only set the DateTimeDigitized
and cameras only
DateTimeOriginal
, but in practice many cameras and image scanning programs set both or neither.
If you want to import your image files into Apple’s Photos application or other image management programs, you need to
set the DateTimeOriginal
and/or the DateTimeDigitized
timestamps.
Please note as well that most cameras do not include time zone information in these fields, so the date & time are in
“camera time”: whatever the camera’s clock was set to when the photo was taken. You can use A Better Finder Attributes’
Adjust Content Creation Date
action to batch adjust this time in your photos.
Some digital photos also contain TIFF
meta-data, such as the TIFF Create Date
. A Better Finder Attributes can
manipulate this date or remove it altogether. Some applications confusingly present this as the DateTimeDigitized
,
so if A Better Finder Attributes shows that there is no DateTimeDigitized
in a file but another application disagrees
this might be the reason.
Movie file formats are even more heterogeneous and often contain more than one content creation date. Different
tracks
for instance may have been created at different moments of times. A single scene from a feature movie will have
been assembled from different takes, filmed on different days, etc.. A Better Finder Attributes is not a fully
featured movie editing suite, so it ignores all this complexity in favour of solving a much easier question, namely:
“Where should the movie be put in relation to the photos I’ve taken in my photo management app or in the Finder”?
Only a subset of movie formats are supported and there are four timestamps that can be set:
DateTimeOriginal
& DateTimeDigitized
Content Creation Date
Media Create Date
Many movie formats, especially when taking by digital cameras, support the DateTimeOriginal
& DateTimeDigitized
timestamps that originate in the EXIF
standard. Use them in the same way as for images.
The Content Creation Date
simply designates the appropriate meta-data field of the specific movie format of your file.
It maps to different actual field names in the various supported formats.
Video formats such as QuickTime make a difference between the Content Creation Date
and the Media Create Date
. The
former is when the content was first recorded, while the second is when the media file itself was first created:
say you’ve recorded the opening ceremony of the 2000 Summer Olympics on a video tape, and you have transferred your VHS
tape to DVD in 2012. The content would be created in 2000, the media in 2012. In reality, these tags like many others
are rarely used in a consistent manner, so you are usually best off looking at which ones exist and which one has the
date you’re after.
By default, A Better Finder Attributes will use the DateTimeOriginal
field for image files & the Content Creation
Date
for movie files, but you can override these settings in the popup buttons.
For movie files, you should normally only use the file format specific field (designated by Content Creation Date
) and
you should rarely have occasion for using the others.