User Defined Text Information items (UDTIs) are used by many encoders and audio applications as a convenient place to store additional information.
In FLAC files, Yate uses this field type, along with UDURLs, to store unmapped FLAC items. Similarly in m4a files these fields are used to store non standard items.
As well as the actual text field, there is a Description field which is a short description used to differentiate multiple items in the same file. This field is intended to be unique among all the items in a single file.
The table displays the UDTIs found in the currently selected files.
All editing and manipulation is done via the context menu and is described here.
Important Note: metadata items in FLAC files are case insensitive. Items in MPEG-4 and ID3 based files are case sensitive. While FLAC items are case insensitive they are almost always written in upper case alphabetic characters. In fact various applications do not properly handle FLAC items which are not uppercased. For this reason, if you are defining your own metadata items you must be aware that they will be made valid when stored and read back from FLAC files. If you create an item called Test and you store it to FLAC and non FLAC files, you may end up with UDTIs named Test and TEST, depending on which files are open at any one time. All FLAC items which are not explicitly mapped are either automatically mapped to UDTIs or UDURLs. If you wish to preserve the alphabetic case of a UDTI which will get stored to a FLAC file, you must explicitly map it to be a User Defined Text item in Preference - FLAC Mappings.
Note that the formatting of these items is very loose. A single item can consist of text with newline characters or of multiple values separated by the multi-value delimiter. When editing these items make sure you set the Separate multiple values option according to your usage.