Sure, thanks. There is a setting in iTunes under the Controls menu, where you can set it to "shuffle" by either Song, Album, or Grouping. Let's say you pick shuffle by "song". Then, let's say you just go to a list of ALL your songs, and start playing a track. It will pick one at random, and then pick the next one at randon, and just keep going. If you started playing a track from the "Albums" list this way, it will play a song from that album at random, and then pick the next one from that album at random, etc., until all tracks from that album have been played. If you hit play on a playlist, it will choose a song from that playlist at random, and choose another track from that same playlist at random, until all the tracks in the playlist have been played.
You can also shuffle by album. This means when you just hit play, and it will choose an album to play at random (with the songs/tracks in order), and then pick another album, etc.
Neither of these were very useful to me. I have a lot of live concert recordings, where certain tracks really need to be played together, like "Not Fade Away" into "Jam" into "Not Fade Away (reprise). More of an issue is classical music. Shuffling by "song" or "album" doesn't work well for this. I have A LOT of Classical albums that are made of more than 20 CDs. Some are over 80! They are all in one "album". Shuffling by "album" doesn't work well for this if what I want is random music, as it will always start the album of 80 CDs at the beginning. Shuffling by "Song" doesn't work - you get the 3rd movement of one symphony and then the first movement of some Concerto!
I had never used the iTunes field "Grouping" before, and didn't know what it was for. But, then I noticed one day that the Shuffle feature has one other option besides Song and Album. You can Shuffle by Grouping! You can populate the Grouping field with ANYTHING you want - it's an organizational field so to speak. I realized I could populate each individual CD (rather than a whole album) with it's own unique Grouping information. For instance, for an album called "Elgar: Collector's Edition", which has 30 CDs all in the ONE album (iTunes gives you a Disc# field to separate albums into discs), I can populate the Grouping field for each CD in the album with "Elgar: Collector's Edition - D1", and "Elgar: Collector's Edition - D2" ... "Elgar: Collector's Edition - D30". I used MP3Tag to easily populate the Grouping field, which until recently was mapped to the ContentGroup tag in mp3 files. It only took a few minutes to give every CD in my iTunes library of over 2,700 albums (far more actual CD's, as many or most of the albums have more than one CD), their own unique Grouping info. Each CD has its OWN Grouping info.
Now, when I use the shuffle feature in iTunes to shuffle by Grouping, I can choose a Playlist, like "Classical Vocal", and it will shuffle by Grouping, meaning it will pick a Grouping in that playlist (which is now one DISC in that playlist), play it through in its entirety in order, and then it will pick another Grouping (from that playlist) at random (another DISC at random) and play it through, etc.
So, I use the Grouping field to be able to play DISCS in their entirety at random, from any playlist, or from my entire library.
The real issue at the heart of this is that iTunes ONLY lets you shuffle by those three categories - song, album, grouping. Since it has fields to populate disc, composer, artist, etc., there's no reason why they don't let it shuffle by ANY of those fields. But, since they only allow those three, I found a PERFECT solution for my "random" issue, which was that neither "song" nor "album" were very useful for when I wanted to listen to "random" music. Grouping gave me a perfect way to do what I wanted. Also, I'm using the field EXACTLY the way that it was intended, in the sense that the Grouping field was only there to give the user one more way to organize their database. Users could decide for themselves what tracks get "Grouped" together by having the same information populated in their Grouping field.
Now, iTunes went and changed the way the Grouping field works. It no longer maps to the ContentGroup ID3 tag. For a while, it no longer mapped to ANY ID3 tag. Now, I'm reading that maps to the GRP1 ID3 tag, but I don't see that - maybe because MP3Tag doesn't support it yet. It appears they did this solely because they decided to use the ContentGroup field for something else.
So, let's say I buy a couple of albums that each of 30 or 80 CD's (not uncommon in Classical Music collections now - like the complete EMI recordings of Rostropovich). It's ridiculous to have to manually edit the Grouping fields in iTunes which takes FOREVER, and you would need to manually do it for each disc. Using MP3Tag, this used to take seconds. I would highlight all the mp3 files after I ripped them from CD. Then I would MP3Tag to edit the ContentGroup tag using the formula "%album% - D%discnumber%" to give each Disc it's own unique Grouping information, and voila, it's ready to be used when I play music using shuffle by Grouping, which because of the way I'm using the field amount to Shuffle by Disc. Think of it this way. iTunes intended users to use the Grouping field for any organizational purpose they wanted. Let's say you wanted to use it by populated it with either Sad, Happy, Meloncholy, Angry, Jubilant, etc., Then using Shuffle by Grouping you could shuffle and play only the tracks labeled Jubilant within any playlist or your entire your library. Since they included Grouping as one of only three different fields that you can shuffle by, this kind of thing is clearly how they intended the field to be used. But, what they've done is gone and made it seemingly impossible to use a 3rd party tool to POPULATE this field. And, with a large enough database of music, it's simply not feasible to populate this field using the iTunes user interface, so they basically made the field useless.
I'm hoping the MP3Tag adds a way to write to an ID3 tag that populates the Grouping field, the way writing to the ContentGroup tag used to work. As I said, I read that populating the GRP1 tag will now populate the Grouping field in iTunes, but I tried this using MP3Tag, and it currently doesn't work that way. Unless I'm doing it wrong, in which case I'm hoping someone can tell me what I'm doing wrong.
Attached is a screenshot of the iTunes Shuffle feature.
Thank you for responding!! 