Picard is the next generation MusicBrainz tagging application. This new tagging concept is album oriented, as opposed to track/file oriented like the ClassicTagger was. Picard is written in Python, which is a cross-platform language, and makes use of cross-platform libraries - this allows the same code to run both on Windows, Linux and Mac OS X.
This tagger takes an album approach to tagging, whereas the old tagger required the user to work with one track at a time and check to see if the tagger correctly identified the track. The amount of time spent reviewing the old tagger's suggestions will probably equal the amount of work the user has to do to find the right albums in the new tagger. More details on this thought later -- first let's explain the basic new operations.
Start with opening individual music files or directories by dragging them into the left-hand pane. The tagger will read the metadata from each of the files and unless they have been tagged before, the files will be deposited into the "Unmatched files" folder. Files that have been tagged before and contain the MusicBrainz track identifier will be opened up as releases in the right-hand pane.
Once the tagger finishes processing the files, press the "Cluster" button (white square with 'clusters' on them). This will cause the tagger to attempt to group the files into album clusters by examining the metadata read from the files and clustering files that appear to belong to the same album. Files that are not matched into album clusters will remain in the "Unmatched files" folder. In future the tagger will automatically cluster the files when it has finished reading the metadata from the files.
This is where the magic currently ends -- from now on you will need to look up album clusters or individual files by selecting the cluster or file and clicking on the "Lookup" button. This will open a web browser window where you can browse/search for the appropriate album using the MusicBrainz web-site. Once you've found the right album, click on the 'tagger' icon in the album title: mblookup-tagger . Once you click on this link, the tagger pops up and loads that album into the tagger.
Now you can drag tracks from the "Unmatched files" folder or from the clusters onto tracks in albums. Dragging a file to an album 'tags' it to that album and you should see an icon in front of the track:
*a green check mark indicates the track is up to date and saved.
*a small rectangle ranging from red to green indicates the quality of the match. red -> bad match, green -> good match
*a blue ? indicates an unmatched file.
*a red error triangle means the file has an error. See the status bar in the bottom of the picard window to see the error.
*a red-and-white "No entry" sign means that Picard doesn't have permission to write to that file, so that it can't save any changes (to correct this, look into the permissions on the file system and directory holding the file)
*a musical note icon, or no icon, means that no file is associated with that track
You can also drag whole directories, multiple files or album clusters onto albums and the tagger will attempt to match the dragged files to the album. Any track that doesn't match up well enough, will be added to an "unmatched files" sub-folder specific to that album. You can drag files out of this folder and into the right slots in the album to fix up the files the tagger couldn't get right.
Once you've matched up your tracks to albums you can select a track or an album and click on the save button to save that track/album. Depending on your settings this may move the track to a new directory and/or rename the track according to its metadata. Take a look at the options dialog to fine tune your settings.
Once you've saved a file, or otherwise want to get rid of a track or album, select the track and click on the delete button in the toolbar.