Apple iTunes’ Party Shuffle algorithm revealed: how song ratings affect tracks’ play chances

“iTunes’ available song ratings of 1 to 5 stars allow users to quickly find their favorites and help the Party Shuffle feature play more of what they like most. This article explores the algorithm iTunes uses to pick what comes next in the playlist,” Brian E. Hansen writes for OminNerd. “After hearing one artist played over and over during a shuffled play of your entire music library in iTunes you may think your player has a preference of its own. Apple claims the iTunes’ shuffle algorithm is completely random. The shuffle algorithm chooses songs ‘without replacement.’ In other words, much like going through a shuffled deck of cards, you will hear each song only once until you have heard them all… or until you have stopped the player or selected a different playlist.”

Hansen writes, “iTunes Party Shuffle is a different matter. Its algorithm selects songs ‘with replacement,’ meaning the entire deck of cards is reshuffled after each song is played. The play higher rated songs more often option does exactly what it says, but how much preference is given to higher rated songs?”

Full article here.


  1. I think most people don’t actually want a pure random setting. I dislike hearing a song too often and I also like to hear my favorite songs more often, but also not repetitively. So, I have set up 5 playlists that give me what I think is a good mix of my songs. They are as follows:
    1: rated 2 and 25 rated by least recently
    2: rated 3 and 73 rated by least recently
    3: rated 4 and 70 rated by least recently
    4: rated 5 and 32 rated by least recently
    playlist is any of playlists 1, 2, 3, or 4 with live updating

    The numbers (25, 73, 70, and 32) come from multiplying the number of songs in each category by the rating-1, so it is essentially the same as the “play higher rated songs” in PartyShuffle. I leave 1 rated songs for ones that I don’t listen to very often. This way, I get a random selection of my music that does not repeat a song until I have more-or-less gone through the rest of them in that rating. And, it generally plays the 5 rated songs about 4 times more than the 1 rated songs.

    I found that I do not like the random feature since it often will play one song significantly more than another song. Eventually, it would even out, but in the range of 20 times playing a song, there can be a large discrepancy and I haven’t heard some songs in longer than I’d like.

    I think the general random setting should randdomly select from a pool of the 20% least recently played songs with live updating. At least, that is how I wish my CD playing in my car worked – I hear the same song played twice in a row about every 10-15 hours of listening.

  2. This guy is talking about ‘Party Shuffle’ not the straight up ‘Shuffle’ option.

    So of course it has some sort of ‘intelligent’ (or if you prefer ‘stupid’) method of shuffle-i-sa-shun…

    Also – how much time do these OmniNerds have on their hands?!…

  3. Quevar, thanks for the suggestion. I’ll have to set that up, since I’ve been wanting that sort of a thing. ” width=”19″ height=”19″ alt=”smile” style=”border:0;” /> (Now if only iTunes would make playlists tree-able, so I didn’t have to have 100’s of playlists to scroll through on my iPod).

  4. Come on, Hang on, dont you know how important it is that Quevar not listen to songs he doesn’t like a lot too much, and that he hear the ones he does like just the right amount? Any amount of time spent on such fine tuning is VITAL and must be allocated without restriction.

  5. I have 6 playlists used to control how often I hear a song

    One star – song rated one star and not played in the last 8 weeks
    Two start -song rated two stars and not played in the last 6 weeks
    Three stars -s ong rated three stars and not played in the last 4 weeks
    Four stars – song rated four stars and not played in the last 3 weeks
    Five stars – song rated five stars and not played in the last 2 weeks

    Rotation – plays playlists one star, two star to five star

    This plays higher rated songs more frequently, and if I need a 5 star fix I can just play the Five star playlist as such.

  6. The playlist that I use most often is this one:

    1. Last played in the last 90 days.

    2. Not played in the last 3 days.

    3. Rating of 3 stars or higher.

    I have another one that I also use, which is basically the same, with a fourth rule added:

    4. Playcount is less than 10.

  7. This is getting a bit more subjective, however I a lot prefer the Zune Marketplace. The interface is colorful, has extra aptitude, and some cool options like ‘Mixview’ that let you rapidly see related albums, songs, or other customers associated to what you are listening to. Clicking on a kind of will center on that merchandise, and another set of “neighbors” will.come into view, allowing you to navigate around exploring by related artists, songs, or users. Talking of customers, the Zune “Social” can be great enjoyable, letting you discover others with shared tastes and b.coming pals with them. You then can hearken to a playlist created primarily based on an amalgamation of what all your friends are listening to, which is also enjoyable. These concerned with privateness will likely be relieved to know you’ll be able to forestall the public from seeing your personal listening habits in the event you so choose.

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