FreeDB and MusicBrainz Search
FreeDB and MusicBrainz are the Internet services which MuRip uses to obtain artist, album and track information for a CD. Each CD has a [usually] unique Disc ID which is used to look up the CD in the database. The CD's "table of contents" TOC is also used to ensure an exact match if the Disc ID is a duplicate.
FreeDB is one of the original free CD databases, but it still works well. MusicBrainz provides its own database and API using a more sophisticated ID. (MusicBrainz stopped supporting the FreeDB gateway in 2019, see https://wiki.musicbrainz.org/History:FreeDB_Gateway. MuRip now uses the new MusicBrainz API, see https://wiki.musicbrainz.org/Development.)
Press the 'FreeDB Search' or 'MusicBrainz Search' buttons to find the CD. This displays the search results. If the CD is not found, then try the other one, or try the unique Barcode Search feature. If all of these fail, then you have a very rare or a very new CD, and you will have to enter the details manually. You can add unknown CDs to the FreeDB database using FreeDB Submit.
Below is an example search which has found five versions of the same CD in the FreeDB database.
The upper pane shows a list of all the CD entries. The lower pane shows the artist, album, track and other information about the entry.
You can select a CD entry in the upper pane, and view the details in the lower. If you find a suitable definition, press the 'Select' button to fill in all the details on MuRip's main page. If the data is not perfect, you can edit it before starting the rip.
Tip: If access to the FreeDB server fails, you can change the server URLs from the Options page, 'FreeDB Server URL' and 'MusicBrainz Server URL'. Google "freedb" to find out which FreeDB servers are currently available.
Sometimes you may see strange characters or question marks "????" in the Artist, Album and/or Track names. This could be because the information was submitted using the ANSI character set instead of the more recent UTF-8, and the computer had a different "code page" installed for a different language, see Wikipedia Code Page. Unfortunately, the FreeDB database does not contain the code page number, so the text cannot be displayed with the correct character set. (But it will probably look OK when displayed on the computer which submitted it.) MuRip always uses UTF-8 encoding when it submits new CDs, so this problem will not occur.
If an exact match for the CD is not found, FreeDB may show entries which are very close but have different disc IDs. In some cases this may be a different release of the CD.
This opens a window showing the raw data received from the database.
If the 'Matching Items' list shows "[INVALID CDDB DATA]", it means that MuRip noticed serious errors in the received data. This should never happen because the server should have rejected the submission. The "Submitted via" entry might reveal the name of the offending application.
If you want to know more about the FreeDB server protocols, you can read the original documentation: freedb.howto.txt