What is Gapless Playback on the iPod and in iTunes? (Update)

One of the major announcements that Apple made on September 12 was that the latest video iPod (the 5G model) offers gapless playback, and that this feature is available for previous video iPods when updated with the latest firmware. While those who know what gapless playback means embraced this with a loud “Huzzah!”, others are scratching their heads trying to figure out what this means. Here’s an overview of what gapless playback is, how it works, and why you might want it.

Gapless playback is simply the ability for the iPod to play music with no artificial gaps between tracks. For most music, you’ll never notice the difference, but if you listen to operas, dance mixes, or classic progressive rock albums (the standard examples are Pink Floyd’s Dark Side of the Moon or the Beatles’ Sergeant Pepper’s Lonely Hearts Club Band), you’ll hear a jarring half-second space between tracks that are meant to continue seamlessly. This lurch is the audio equivalent of an elevator dropping a floor suddenly, and ruins the listening experience. Fans of live music (The Grateful Dead, and other jambands) especially hate this, since this type of music often has songs that segue from one to another with no break. Finally, Apple answered the call, making the new iPod the only current portable music player that offers gapless playback. (Note: naysayers will point out that the Rio Karma has gapless playback; I said that no current portable music players offer this feature. The Rio Karma is no longer being sold.)

When I wrote about gapless playback here about a year ago, I offered a workaround that would allow classical music fans to rip their music so it could be gapless. The idea was that you simply join tracks when ripping albums, so instead of multiple tracks with numerous hiccoughs, you’d have a single track for an entire work. This is okay, but it’s a workaround; you wouldn’t be able to find which track you were listening to. Now, with gapless playback, operas can have individual tracks, and you won’t heard the difference.

Of course, there’s a down side to this: now classical music fans who did rip their music with joined tracks will probably want to re-rip these discs; I know I’ll be re-ripping all my operas. Sigh.

So how does gapless playback work? You probably noticed that the first time you launched iTunes, the program took a few minutes to analyze your music for gapless playback. iTunes looked at your tracks to determine if there was no silence at their ends to flag them as tracks that would flow smoothly into the following tracks. This works in iTunes, as well as with all 5G iPods and the new iPod nano. However, this does not work with previous iPod models. Curiously, this process works automatically, though there is a “Part of a gapless album” tag that can be set for individual tracks. It’s not clear if this tag exists to turn on gapless playback or to turn it off. Initial reports say it’s not needed for gapless playback (it certainly isn’t needed with iTunes); I’m awaiting a new iPod to test it there and figure out exactly what it’s for. (Yes, I don’t yet own a video iPod.)

Stay tuned for an update to this article in a week or so when I’ve fully figured out how this tag affects playback on the iPod. For now, be happy (if you find gapless playback useful) or yawn if you don’t. I, for one, applaud the fact that Apple listened to its users and provided this needed feature.

Update: Apple has cleared up the question about the gapless tag. They say this tag only matters if you have crossfade playback turned on in iTunes, and it only affects playback from iTunes. All gapless albums are automatically detected and played as such on 5G iPods (video-capable iPods) and 2G iPod nanos (the latest versions of the nano).

14 thoughts on “What is Gapless Playback on the iPod and in iTunes? (Update)

  1. I was really happy to see gapless playback implemented so well. It works
    wonderfully on my iBook, but had not yet experienced it on my 4G iPod. I’m
    disappointed that it doesn’t work on any iPod that is not currently offered—my
    iPod is not quite one year old! But I’ll take what I can get—at least it sounds
    great on my computer…

  2. I was really happy to see gapless playback implemented so well. It works
    wonderfully on my iBook, but had not yet experienced it on my 4G iPod. I’m
    disappointed that it doesn’t work on any iPod that is not currently offered—my
    iPod is not quite one year old! But I’ll take what I can get—at least it sounds
    great on my computer…

  3. I was under the impression the feature worked on the Nanos
    As for the flag – it is not needed in iTunes. It is needed on the iPod to flag the
    iPod to know to start loading the next song before the current one ends. If the
    flag is not there, it will not pre-load the next song.

    • According to Apple, this is not correct. Their web site explicitly states the flag is required by iTunes, but is only used when Crossfade is switched on. They say that in iTunes 7.x, gapless playback is always on, and the flag simply tells iTunes to override the Crossfade setting for tracks where the gapless flag has been manually set to "yes". That is, if you use Crossfade, gapless tracks will also crossfade unless this setting has been manually switched to "yes". (It also clarifies the two different settings. The album setting, "Gapless album", is just a shortcut to mark all its tracks as gapless, so you don’t have to set each track one by one. Meaning: it is the individual track setting that really matters.) And re the iPod, the web site also explicitly states "iPod does not support crossfade playback and only some iPod models support gapless playback. For those models that do, all files that support gapless playback are played gaplessly whether or not the "Part of a gapless album" option is checked." Cheers!

  4. I was under the impression the feature worked on the Nanos
    As for the flag – it is not needed in iTunes. It is needed on the iPod to flag the
    iPod to know to start loading the next song before the current one ends. If the
    flag is not there, it will not pre-load the next song.

    • According to Apple, this is not correct. Their web site explicitly states the flag is required by iTunes, but is only used when Crossfade is switched on. They say that in iTunes 7.x, gapless playback is always on, and the flag simply tells iTunes to override the Crossfade setting for tracks where the gapless flag has been manually set to "yes". That is, if you use Crossfade, gapless tracks will also crossfade unless this setting has been manually switched to "yes". (It also clarifies the two different settings. The album setting, "Gapless album", is just a shortcut to mark all its tracks as gapless, so you don’t have to set each track one by one. Meaning: it is the individual track setting that really matters.) And re the iPod, the web site also explicitly states "iPod does not support crossfade playback and only some iPod models support gapless playback. For those models that do, all files that support gapless playback are played gaplessly whether or not the "Part of a gapless album" option is checked." Cheers!

  5. This is great news for me. I have a 4G (pre-photo) iPod and each new firmware or iPod release I check for this feature. This time I forgot so this is a great surprise for me. Enough to have me thinking of replacing my 4G.

    I’m definitely interested in the results of your test on the "gapless" attribute. I’m sure it won’t do this, but something I think they should add is the ability to tie tracks together. I listen mostly in random order and when I get to the occasional song which is actually split across two tracks on the CD it’s a bit unnerving when it ends abruptly. So I’d like a way (without manually ripping them) to "tie" the first to the second so the second always follows the first no matter if the first was played via randomization, playlist, whatever.

  6. This is great news for me. I have a 4G (pre-photo) iPod and each new firmware or iPod release I check for this feature. This time I forgot so this is a great surprise for me. Enough to have me thinking of replacing my 4G.

    I’m definitely interested in the results of your test on the "gapless" attribute. I’m sure it won’t do this, but something I think they should add is the ability to tie tracks together. I listen mostly in random order and when I get to the occasional song which is actually split across two tracks on the CD it’s a bit unnerving when it ends abruptly. So I’d like a way (without manually ripping them) to "tie" the first to the second so the second always follows the first no matter if the first was played via randomization, playlist, whatever.

  7. I just got the new iTunes and iPod versions installed last night (I have a 60GB video iPod). The gapless feature certainly works, though it is not perfect. I have a ton of albums that need this and it really used to bug me. These albums include more than 40 Frank Zappa albums (many of them 2 or 3 CDs) and on most of these, the tracks segue (even the studio albums). I also have a huge collection of various live albums, plus other studio albums from artists who like to segue tracks (like Pink Floyd). So this is terrific. Unexpected bonus: fans of ZZ Top will know about the famous pairing of "Waitin’ For The Bus" and "Jesus Just Left Chicago" on the Tres Hombres album. These songs don’t actually segue, but the second sort of comes in a little too early. It was actually a mistake during mastering, but they liked it, kept it that way, and now these two songs are forever joined at the hip, even being played that way live. Previously, I had to join them into a single track, because the artificial gap imposed by iTunes was really jarring, but I’ve resplit them now and it works fine. Bad point: I can still detect minute gaps in Pink Floyd’s The Wall, not every track but definitely a few. Sounds like a minuscule dot of static. And one comment on the main article: Jethro Tull’s ‘Thich as a Brick" is hardly a standard example of albums that need gapless playback. The album consists of one song but it has always been split into two distinct halves: this goes right back to the original recording on LP, which had one-half on each side, so the song is not only recorded that way, it’s actually written to account for that. There are no breaks within each half (and never have been, even before gapless playback on the iPod), and now adding gapless playback between the halves would make no sense (haven’t tested this yet to see iPod treats it, will do so later). And finally, Apple’s explanation of the manual "gapless" settings doesn’t really make sense. They say the setting is only there to force gapless tracks to be honored when you are using cross-fades. In this case, why not have a global preference ("Honor gapless tracks when using cross-fade")? In fact, if this is the intent, the wording of the setting should be changed, because now it is clearly misleading, as evidenced by lots of posts I’ve seen from people who wonder why gapless albums play properly even though this flag is NOT set. The cross-fade setting is global, so it would make sense to add an option under that preference. I don’t understand why, when using cross-fade, someone would want to preserve gapless playback for some albums but not others! Now, the settings are called "Gapless album? Yes | No" (for albums) and "Part of a gapless album? Yes | No" (for individual tracks); these default to No even when iTunes/iPod know the albums/songs are gapless; but despite the No setting, gapless is in fact honored! Sorry for the long reply! Cheers!

  8. I just got the new iTunes and iPod versions installed last night (I have a 60GB video iPod). The gapless feature certainly works, though it is not perfect. I have a ton of albums that need this and it really used to bug me. These albums include more than 40 Frank Zappa albums (many of them 2 or 3 CDs) and on most of these, the tracks segue (even the studio albums). I also have a huge collection of various live albums, plus other studio albums from artists who like to segue tracks (like Pink Floyd). So this is terrific. Unexpected bonus: fans of ZZ Top will know about the famous pairing of "Waitin’ For The Bus" and "Jesus Just Left Chicago" on the Tres Hombres album. These songs don’t actually segue, but the second sort of comes in a little too early. It was actually a mistake during mastering, but they liked it, kept it that way, and now these two songs are forever joined at the hip, even being played that way live. Previously, I had to join them into a single track, because the artificial gap imposed by iTunes was really jarring, but I’ve resplit them now and it works fine. Bad point: I can still detect minute gaps in Pink Floyd’s The Wall, not every track but definitely a few. Sounds like a minuscule dot of static. And one comment on the main article: Jethro Tull’s ‘Thich as a Brick" is hardly a standard example of albums that need gapless playback. The album consists of one song but it has always been split into two distinct halves: this goes right back to the original recording on LP, which had one-half on each side, so the song is not only recorded that way, it’s actually written to account for that. There are no breaks within each half (and never have been, even before gapless playback on the iPod), and now adding gapless playback between the halves would make no sense (haven’t tested this yet to see iPod treats it, will do so later). And finally, Apple’s explanation of the manual "gapless" settings doesn’t really make sense. They say the setting is only there to force gapless tracks to be honored when you are using cross-fades. In this case, why not have a global preference ("Honor gapless tracks when using cross-fade")? In fact, if this is the intent, the wording of the setting should be changed, because now it is clearly misleading, as evidenced by lots of posts I’ve seen from people who wonder why gapless albums play properly even though this flag is NOT set. The cross-fade setting is global, so it would make sense to add an option under that preference. I don’t understand why, when using cross-fade, someone would want to preserve gapless playback for some albums but not others! Now, the settings are called "Gapless album? Yes | No" (for albums) and "Part of a gapless album? Yes | No" (for individual tracks); these default to No even when iTunes/iPod know the albums/songs are gapless; but despite the No setting, gapless is in fact honored! Sorry for the long reply! Cheers!

  9. People are saying that it is only newish iPods which support gapless playback. This isn’t quite correct. My iPod is now 6 years old and soon after I got it I found the jarring 0.5 sec gap that it inserted at track number changes. After some effort I was told how to eliminate this by one of Apple’s Genius bar helpers. Unfortunately I can’t find that information now and I have just found that with the latest iTunes software the gap is back on new stuff transferred to the iPod; checking the gapless album and part of a compilation and re-transferring doesn’t make any difference. (So an old iPod which used to have a gapless feature no longer does, it would seem.) Anyone got any ideas how to make a true gapless recording on an old iPod?

    • Gapless playback was added an 2006, when I wrote this article.

      The gapless playback tag only works with crossfade playback, and prevents such tracks from being faded.

      I’m surprised that your iPod that old does gapless, but perhaps there was a firmware update that added this feature. Otherwise, I can’t think of any trick that would turn it on.

  10. People are saying that it is only newish iPods which support gapless playback. This isn’t quite correct. My iPod is now 6 years old and soon after I got it I found the jarring 0.5 sec gap that it inserted at track number changes. After some effort I was told how to eliminate this by one of Apple’s Genius bar helpers. Unfortunately I can’t find that information now and I have just found that with the latest iTunes software the gap is back on new stuff transferred to the iPod; checking the gapless album and part of a compilation and re-transferring doesn’t make any difference. (So an old iPod which used to have a gapless feature no longer does, it would seem.) Anyone got any ideas how to make a true gapless recording on an old iPod?

    • Gapless playback was added an 2006, when I wrote this article.

      The gapless playback tag only works with crossfade playback, and prevents such tracks from being faded.

      I’m surprised that your iPod that old does gapless, but perhaps there was a firmware update that added this feature. Otherwise, I can’t think of any trick that would turn it on.

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