how does itunes select tracks for shuffle?

[zone_ahead]

it doesn't seem to be completely random.

 

i've got maybe 400 plus albums ranging in a variety of genres but i always seem tracks from certain albums and genres come up much more often than others.

 

like there's probably 15 albums that i can guarantee at least one of a track off of one of them will show up almost every time i hit shuffle. like i have quite a few flaming lips albums on there, but for some reason more often than not a track from a day they shot a hole in the jesus egg will come up. i've started paying attention to this and i've never seen a track from either soft bulletin or yoshimi come up in shuffle in the last month and that's pretty daily use of itunes.

 

now i notice this with genres too. maybe 10% of my collection is hip hop, but it usually pops up closer to a 1/4 of time; a lot of the time the same tracks too. i have way more reggae and that doesn't come up on shuffle nearly as much.

 

i don't rate any of my tracks and don't have that filter or any other turned on as far as i can tell. they aren't tracks that i play often, but not tracks that i've never listened to either.

 

it's all in one music folder, but divided into sub folders by stuff downloaded by itunes, emusic, bleep and then my cd's i've ripped.

 

anybody know? maybe i'm just selectively paying attention, but i don't think so.

[Anderton]

Several people have questioned the "randomness" of iTunes. I really don't know, but do remember that if something is truly random, it won't pay any attention to what has come before. So it's entirely possible that songs will repeat. If they didn't, that would be an indication of a lack of randomness.

 

I have a Zen that has a "play any track" feature. Today it played two Byrds songs in a row, but they were from different albums entirely. Then a whole bunch of seemingly random tunes appeared, but who knows....

[boosh]

In theory it is even possible you get the same song twice in a row.

[zone_ahead]

yeah, i wondered if i was just seeing random short term anomalies. but after a while you would think that due to predictability and chance that it would mostly come out pretty even for the make up of the tracks. like if you flip a coin enough times.

 

but like i said, aside from personal observation, i haven't done any real tests (nor would i really want to).

[Zooey]

There is a way to not repeat songs: determine a random playlist in advance containing all songs, and not start the sequence over again (or create a new sequence) until it has been played all the way through. The playlist is randomly determined in advance, but it's fixed in the memory until it has been played through.

 

I don't know if iTunes works this way, but the iPod shuffle definitely does. It won't repeat a song until all other songs have been played. If you turn it off and on again, it starts from the last song you played. I think it reshuffles the order only when you plug it into a computer again.

 

Think of it like a pack of cards. If you shuffle the cards, and draw them one by one, you're not going to get the 10 of diamonds twice. That doesn't mean the order isn't random, does it?

[MorePaul]

Originally posted by Anderton

Several people have questioned the "randomness" of iTunes. I really don't know, but do remember that if something is truly random, it won't pay any attention to what has come before. So it's entirely possible that songs will repeat. If they didn't, that would be an indication of a lack of randomness.

 

It depends on WHAT we are randomizing

 

If we are randomizing track SELECTION then history wouldn't come into play

 

If, however, we are randomizing track ORDER, this could be encoded as selection history

 

EDIT : oops, I just said what zooey already said

 

 

[polyt]

Came accross this recently:

 

http://arstechnica.com/journals/apple.ars/2005/8/28/1066

[blue2blue]

I bought a Sandisk memory player about 6 weeks ago and its 'shuffle' mode seems to have some peculiarities, as well. I typically run it in shuffle with 'Resume' on (IOW, it's supposed to pick up where it left off.)

 

There are two ways of turning it off -- holding the power button for about 3 or 4 seconds (until you see the "Goodbye" screen) or putting it in pause with a tap of the same control and then just letting it turn itself off after 30 seconds or so. But when you do the latter, it seems to drop back 4 or 5 songs. If, OTOH, you switch it to FM or mic recording, it appears to start over with a new shuffle sequence. I guess. Honest to gosh, it's been hard to pin down its behavior and I've been sussing wierd software behaviors for 20 years as part of my dayjob (not to mention a side aspect of audio work, at times.)

 

 

Oh, and don't forget, there's a diff between shuffle and random, at least in general usage. Random often means just that, making it possible to have the same song play twice. Shuffle, OTOH, usually refers to a mode that avoids repetition. (I've even heard of 'smart shuffle' on CD jukeboxes that won't play two songs fromt he same CD in a row. But I've never owned such a beast.)