Nested playlists

[mwalimu]

Is there a way to set up playlists and/or folders that will do something like the following:

A folder contains a large number of entries, most of which are individual .mp3 files, but a few are playlists pointing to files in another folder (possibly but not necessarily subfolders of this one).  When the main folder is played on shuffle and it encounters one of these nested playlists, it plays through it in order before going back to the next shuffled entry in the main folder.

I'm not necessarily bound to using nested playlists if the same result can be accomplished another way, such as by having the songs grouped in the playlists located in subfolders to the main folder, as long as it achieves the result of having two or more files treated as a unit and played together in order in an otherwise shuffled playlist.  The point is, it must group the tracks and play them as a unit; any solution that would effectively pull the tracks from the nested playlist (or subfolder) into the main playlist and treat them as individual tracks misses the point.

Searching the forums I found a couple of requests for a way to do album shuffle; in one of them the OP implied that he figured out a solution but didn't provide any details how he did it.  What I'm asking for could be comparable to shuffling a combination of albums and individual tracks.

A few other factoids:  If it matters, I'm using a Sansa Fuze v2.  All of the files in question are .mp3s I will have probably over 3000 tracks in the main playlist with somewhere between 50 and 100 of these groups as described above (most with only 2 or 3 tracks though some will be longer; one I can think of offhand will have 7).  The groups are all consecutive tracks from the same album; I use gapless, album gain, and no fadeover.

I understand there may be no good way to achieve this with Rockbox.  If so I'll have to either re-rip the tracks from the CDs or (if I no longer have access to the discs) open up Audacity and cut and splice them into single tracks, but I thought I would ask here first if there is a way to avoid having to do that.

[saratoga]

If the tracks are each in their own folder, then I think the random folder advance plugin might work (although I'm not too sure how it works). 

I'm not certain if M3U playlists are supposed to be able to reference other M3U files, but the idea itself seems ok to me if someone wants to implement it. 

[mwalimu]

I suppose that would work, but when we're talking thousands of tracks and >95% are single tracks, it seems like a lot of overhead to have to put each one in its own folder for the sake of the <5% to be played as part of an ordered group.  How much overhead in terms of storage capacity is a lot of folders going to eat up?  Does Random Folder Advance have a limit on the number of folders it can handle?

[saratoga]

The overhead will be negligible.

[mwalimu]

Okay, I'm trying to read through this, review the documentation, and figure out how feasible this would be.  Something else I neglected to mention earlier, if it makes any difference, is that all of the music files, folders, non-dynamic playlists, and such would be located on their own microSDHC card that I might swap out at times.

That said, here are the potential problems that have come to mind:
 - while creating a folder of each of the groups is reasonable, having to also do it for each of thousands of singular tracks is infeasible; I would have to find or write a program to automate the process;
 - it would be quite cumbersome to maintain when adding/removing tracks or replacing them with better copies, or even to locate them to play, if they're each in separate folders.  I was thinking using Database might be helpful, but then I read Database doesn't play well with auto-change directory;
 - if my guess is correct, auto-change directory plays directories at random rather than shuffling them ("shuffle" plays them once each in random order, whereas "random" chooses one at random each time, possibly the same one it just played) (wrong, see next post);
 - again if my guess is correct, with respect to playlist-related features, it has no ability to work with the larger playlist consisting of the entire set of folders; the only playlist it recognizes at any given time is the dynamic playlist from the current folder (mostly wrong, see next post).

Unless some of my guesses are wrong, this is not looking like a workable solution for me.

[mwalimu]

I just experimented with the setup discussed above, and it appears my guesses were wrong in the third and fourth bullets.

My experiment consisted of creating 12 folders for The Beatles album Abbey Road, which has two of these song suites that should be played together in order.  In one folder I put all four tracks from the first (Sun King, Mean Mr. Mustard, Polythene Pam, She Came in Through the Bathroom Window), in another the three tracks from the other (Sun King, Carry That Weight, The End), and the remaining ten tracks went one in each of the remaining folders.  I copied these to player.

Repeat off.  Shuffle off.  Crossfade off.  ReplayGain album.  Auto-change directory on (this was the only change from my usual settings).  I went to the Random Folder Advance Configuration plugin, had to run Generate Folder List, then edited it to delete all folders except the twelve above (the context menu to delete folder tree made this a lot quicker), and clicked Play Shuffled.  Lo and behold, it created a dynamic playlist with all 17 tracks from all 12 folders!  I reshuffled a few times (again using the plugin's Play Shuffled) and it always kept the tracks from the two song suites together and in order, but otherwise randomized the order, which is exactly the behavior I was hoping for.

So basically my last two bullets are mostly non-problems.  There are still a few gotchas, such as if you go to the normal playlist context menu and reshuffle or insert shuffled, it doesn't respect the folder groupings, but I seldom use those features anyhow.  That still leaves the first two bullets, particularly the matter of creating a folder for each of thousands of songs, but the overall approach is looking a little more feasible.  Too bad there's not a way to tell RFAC to treat a folder as if each song in it were in its own folder.

[mwalimu]

First bullet solved.  Foobar's file operations makes it easy to create a folder for each file (using tag values to generate the folder name) and move the file into it.  I am told MP3Tag also provides this capability. 

The second bullet is looking easy to resolve.  I will likely keep a "master copy" of the entire playlist with their folders on my computer where I will make any changes, and use a folder sync program to apply updates to the mp3 player.

This approach of having to create a folder per file still feels kludgey when most of the songs are singular tracks and relatively few need to be grouped, but hey, if it works...  The only iffy part that remains to be seen at this point is whether the Random Folder Advance Configuration plugin can handle thousands of folders without blowing any performance or capacity limitations.

[mwalimu]

Process complete, and it appears to be a success.  Since I had never actually compiled a playlist of 3000+ of my favorite tracks, that task alone took many hours.  Anyone who has already done this won't need to do what was for me the most time consuming part of the process by far.  Once I had the playlist built, I used Foobar to put each into its own folder except the multi-track song suites, of which all parts of each suite went into one folder.  This was all done on the computer; with the folder setup the way I needed it to be, I plugged in the player and used FreeFileSync to copy the entire set of folders and tracks to the player (which took about 90 minutes; sure, I could have just done a regular Windows copy, but as I anticipate adding, replacing, removing tracks from the favorites over time, this should greatly simplify syncing up what's on the computer with what's on the mp3 player).

The player (running the original Sansa firmware) spent over an hour showing "Refreshing your media" (this normally takes no more than about 30 seconds after adding/removing content from the player) and finally completed.  I shut it off, started it under Rockbox, and it took a few seconds longer than usual to load.  Under RFAC, generated and edited the folder list as described earlier, hit play shuffled (which took several seconds) and I had a playlist of over 3000 tracks, ready to go!

I'm going to run with it a few days, hopefully hitting a few of the multi-track sets, maybe adding some tracks and resyncing.  If all goes well and enough others are interested in doing the same, I can do a cleaner write-up of the whole process.