Click on in the main window to open this window.

In addition to tags stored inside an MP3 file, song information can also be obtained using patterns. In the Tag Editor's context there are 2 kinds of patterns: "file name - based" and "text line - based"; they are used to extract track information from a file's name or from pasted text, respectively. Information retrieved from patterns is displayed alongside that from MP3 tags, in the "current file" table. A pattern is a sequence of characters, the main idea being that a '%' followed by some letters is a placeholder, corresponding to a field, while the other characters are used to separate placeholders from one another. These are the supported placeholders:

Besides these sequences, there are usually "static text" sequences in a pattern. An example: consider the file named

Note that the matching is done from the end of the file name, so the beginning of the name (/music/mp3) doesn't matter. The pattern would get the same fields for a file named /pop/artist1/album1 (2008)/02 second track.mp3 or /home/user/media/music/mp3/pop/artist1/album1 (2008)/02 second track.mp3.

If a pattern contains the path-separator character (\ on Windows and / on UNIX), it is "file name - based", otherwise it is "text line - based". Besides the source of the text (file name vs. clipboard), another difference is that the latter must match perfectly the text, while the former may have errors in any of the strings between consecutive / characters and still extract some fields from other parts of the file name. In the example above the pattern %g/%a/%b {%y}/%n %t would return no album or year, because album1 (2008) doesn't contain { or }, but would still find the genre, the artist, the track number, and the title.

Both kinds of patterns are edited in the "Patterns" dialog. Only valid patterns can be saved. Besides the rather obvious % followed by a character that is not part of the placeholder list above, there's another condition that causes a pattern to be invalid, namely 2 consecutive "unbound placeholders": %n, %y and %r have a fixed format, but the rest are unbound, meaning that they would take any characters as long as there's nothing to tell them where to stop. With 2 unbound placeholders there's no way to tell where one should end and the other should begin. So %a%t is invalid (as is any pattern containing it), while %a-%t is valid, because - is used to identify where the artist name ends and the track title begins. However, %y%t is valid, because %y is a 4-digit number.

Patterns may have optional parts, which are delimited by "[" and "]". One optional part may be embedded in another. (See the predefined patterns for examples.)