A Tip for Filtering by File Dates

[DetlevD]

@Doug Mackie

To make a playlist of "recent additions", I wanted a filter to return all files under my Music folder created after a specified date ... The information field %_file_create_datetime_raw% is available, but there is no way within Mp3tag to get a user-specified timestamp to filter on. The best you can do is to copy an existing timestamp from a file in a custom column. This is awkward and imprecise because you cannot choose the exact date(s) that you want. ...

That is not quite right. Mp3tag provides precise datetime_raw values per file.
Copy and paste the raw value from one place to another place within Mp3tag user interface needs not more time than using an external webservice.
Read there ...
Filter by date?
Filter if "modified date" is greater than "create date"

@Doug Mackie

... Raw timestamps use epoch time (sometimes called Unix time). That is the total number of seconds that have elapsed since January 1, 1970 at midnight GMT, and is the format displayed by both %_file_create_datetime_raw% and %_file_mod_datetime_raw%.
I found a site that makes the conversion easy: www.epochconverter.com You simply enter a normal date in one of their "human date to timestamp" sections, and one click later you have a timestamp value in epoch format. Just paste that number into your filter expression. No need to customize Mp3tag columns. ...

... there is just the need to have a running internet connection.

DD.20120613.0500.CEST