gapless playback on ipod?

[Febs]

Quote:

Originally Posted by elnero /img/forum/go_quote.gif It's been my understanding that MP3 is not a natively gapless codec, are Lame and iTunes doing something to the codec to make it truly gapless or is it that the implementations of gapless require specific conditions to work properly?

Yes. This FAQ from the Rockbox website explains why Rockbox can play LAME files gaplessly even though MP3 is not a natively gapless format:

Quote:

MP3s were not designed to be played back gaplessly; this is a limitation inherent in the MP3 format. MP3 stores data in frames that contain 1152 samples (48/44.1/32 kHz sample frequency) or 576 samples (24/22.05/16/12/11.025/8 kHz sample frequency). Since the length of a song rarely corresponds exactly to a whole number of frames, MP3 encoders "pad" the end of the final frame in the song with additional samples. Unfortunately, most MP3 encoders do not store any information indicating what is padding and what is supposed to be part of the song. Thus, it is impossible for an MP3 decoder to play back an MP3 file gaplessly with two exceptions: (1) LAME 3.90.1 and higher stores information about the exact file length in the header (the LAME tag), thus allowing us to calculate which parts of the final frame are padding and to disregard those samples on playback. (2) LAME and maybe other encoders allow to encode an album in a way that the song ends are slightly shifted to end up exactly on frame boundaries (the LAME -nogap method; the shift is max. 1/2 frame length, i.e. usually not noticeable). These files can be played gapless regardless whether the player handles the LAME tag or not. Note that some MP3 players implement a psuedo-gapless playback using one of a couple of methods of cheating. Some players which claim to be gapless will actually do a very short crossfade between the end of one song and the beginning of the next. Other players cut off any zero data (or near zero data) in the final frame of an MP3. This method, which is sometimes referred to as "gap detect" or "gap delete," is not truly gapless, because (1) is it not accurate, and (2) it will cut off silence that is supposed to be at the end of a track. "Gapless" will play back MP3s of a CD the way the mastering engineer intended it to be; "gap detect" or "gap delete" will not. For example, if the mastering engineer decided to put a 2-second gap between one song and another on a CD, true gapless playback will retain that 2-second gap, whereas gap detect or gap delete will not. Rockbox uses gapless playback, not gap detect or gap delete. What does all this mean? Basically, Rockbox will play back LAME-encoded MP3s either gaplessly or very nearly gaplessly. However, MP3s encoded with other encoders will play back with a small but noticeable gap.

I suspect that Apple's gapless implementation works in a similar fashion.

 

[elnero]

Febs, if you fast forward into a song and then let it play, when using Rockbox does it still playback gapless?

 

[pata2001]

Quote:

Originally Posted by elnero /img/forum/go_quote.gif That may very well be but then why if gapless album is not selected is there gaps? I have one album in particular that I've tried ripping via iTunes and other methods as Apple Lossless, mp3 and AAC, I can get it to play gapless as mp3 and AAC but not as an ALAC. Rockbox has no problem whatsoever with any of the files. So that begs the question if Apple's implementation of gapless is correct and problem free as you say then why are there problems when using their own software to rip? Also, if it's is problems with the tracks not being ripped properly why do those same tracks play without problems with Rockbox?

All my gapless albums don't have the "gapless" info selected, and they play gaplessly just fine.

Nobody ever said that ALAC is gapless on iPod's default firmware. I never tried it, and I don't see anybody claiming ALAC is gapless on iPod's default firmware. All I'm saying is MP3 and AAC is gapless, and you confirmed it yourself, so what's the problem? I'm all for rockbox too, and if you want to use rockbox, by all means do so. I used it, liked it, but since Apple's own firmware offer gapless playback on MP3s and AAC, I don't use rockbox anymore. Maybe Apple's firmware has problems with ALAC due to save battery power, while rockbox doesn't.

Pretty much any lossy codecs are inherently not "purely" gapless, simply due to frame issues. They are gapless capable using tags indicating to the software/player the specific length of the song. I believe OGG, Lame MP3, all use this, and software like foobar/firmware like rockbox will read this tag and produce gapless playback. iTunes use its own tag (hence when you import any tracks, iTunes is scanning the tracks to "determine gapless playback.") iPods presumably only understand iTunes' tags, but any software that can read those tags should be able to give convey gapless playback to the iPod's database.

We can diss Apple all we want, but name any other manufactures that provide gapless Mp3 playback on their DAP. Other than the Trekstor, none.

 

[EFN]

Quote:

Originally Posted by pata2001 /img/forum/go_quote.gif The gapless option in iTunes has NOTHING to do with gapless playback. It only disables crossfade for the selected tracks. The only requirements for gapless playback are: 1. The tracks are actually gapless from the CD (duh) 2. The tracks are ripped properly. (MP3 and AAC ripped via iTunes are gapless, Lame MP3 is gapless too). 3. Let iTunes scan the tracks for gapless information when importing the tracks. 4. Play the songs as an album. The tracks won't be gapless if you shuffle them, for obvious reason. Gapless playback itself is automatic. Why should there be an "on/off" anyway? As for those that have problems, the only thing I could think off is that the tracks are not ripped properly. I have zero problems with gapless playback on my 5G iPod and 2G nano, and I have tons of non-stop album mixes. Ripping the tracks via iTunes will definitely ensure gapless. Ripping via EAC + Lame MP3 also produces perfectly gapless MP3s.

2X.

A properly ripped CD will retain gapless info.

 

[elnero]

hmmmm, I haven't tried it recently but I do remember that initially I had to select gapless album on my tracks before my iPod played gapless. I'll have to try it again without selecting that to see if it works.

 

[oicdn]

1st Gen Nano has gapless. You have to configure it in iTunes oddly enough and check the box that says "this is part of a gapless album" and when the entire album is on my Nano...it's gapless....

Otherwise, the songs aren't gapless unless you check that box for EVERY song you're putting on your iPod...

 

[elnero]

Quote:

Originally Posted by oicdn /img/forum/go_quote.gif 1st Gen Nano has gapless. You have to configure it in iTunes oddly enough and check the box that says "this is part of a gapless album" and when the entire album is on my Nano...it's gapless.... Otherwise, the songs aren't gapless unless you check that box for EVERY song you're putting on your iPod...

That's how I remember my 5th Gen iPod acted when I first put music on it shortly after Apple announced the gapless feature had been implemented and that's how I've done it ever since.

 

[Febs]

Quote:

Originally Posted by elnero /img/forum/go_quote.gif Febs, if you fast forward into a song and then let it play, when using Rockbox does it still playback gapless?

Good question. When I have a minute I will check and let you know.

 

[JayJayz]

so you still need a 5g to play gapless mixes?

or if ripped properly off my cd a 4g can play a whole mix gapless ?

everyone is confusing me. haha.

 

[Henry Flower]

Quote:

Originally Posted by elnero /img/forum/go_quote.gif That's how I remember my 5th Gen iPod acted when I first put music on it shortly after Apple announced the gapless feature had been implemented and that's how I've done it ever since.

Since the gapless playback requires the files to be scanned, and this is done when you add the files to your library, perhaps (just my guess)

- files added to your library before gapless playback was introduced need to be rescanned (tagging as gapless albums might prompt this). Otherwise iTunes and the iPod don't have the information needed to play gaplessly.

- files added after gapless was introduced are automatically scanned and so are automatically played gaplessly.

What Apple itself says is:

Quote:

Gapless Playback on iPod 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.

http://docs.info.apple.com/article.html?artnum=304362

And for Jayjayz:

Quote:

Supported iPod models (make sure you have the latest iPod Software) * iPod nano (Second Generation) * Fifth Generation iPod * Fifth Generation iPod (Late 2006)

 

[immtbiker]

So does this mean...if I skip the ephpod and start using iTunes, and choose the gapless platback option, then all of my music will be played gapless regardless of whether they are originally, or not?
I wouldn't want gapless platback on albums that don't originally run the tracks into each other in the first place.

It seems like an all or nothing proposition to me. That's as bad as not having the GP option.

 

[elnero]

Quote:

Originally Posted by immtbiker /img/forum/go_quote.gif So does this mean...if I skip the ephpod and start using iTunes, and choose the gapless platback option, then all of my music will be played gapless regardless of whether they are originally, or not? I wouldn't want gapless platback on albums that don't originally run the tracks into each other in the first place. It seems like an all or nothing proposition to me. That's as bad as not having the GP option.

No, albums that weren't meant to flow together won't suddenly start blending tracks, it's only tracks that were meant to flow together that previously had a bit of a hiccup between that will now flow smoothly.

As I understand it now you would have to reload your tracks using iTunes or other software that supports gapless on the iPod. Again, from what people are suggesting selecting the gapless album option is not necessary, as long as the tracks are encoded properly they are supposed to work.

 

[immtbiker]

Thanks for the info and your clarification efforts for me, elnero. Mucho appreciato.

 

[Chri5peed]

Quote:

Originally Posted by Febs /img/forum/go_quote.gif Note that some MP3 players implement a psuedo-gapless playback using one of a couple of methods of cheating. Some players which claim to be gapless will actually do a very short crossfade between the end of one song and the beginning of the next. Other players cut off any zero data (or near zero data) in the final frame of an MP3. This method, which is sometimes referred to as "gap detect" or "gap delete," is not truly gapless, because (1) is it not accurate, and (2) it will cut off silence that is supposed to be at the end of a track. "Gapless" will play back MP3s of a CD the way the mastering engineer intended it to be; "gap detect" or "gap delete" will not. For example, if the mastering engineer decided to put a 2-second gap between one song and another on a CD, true gapless playback will retain that 2-second gap, whereas gap detect or gap delete will not. Rockbox uses gapless playback, not gap detect or gap delete. What does all this mean? Basically, Rockbox will play back LAME-encoded MP3s either gaplessly or very nearly gaplessly. However, MP3s encoded with other encoders will play back with a small but noticeable gap.

^ Not Feb's words.


Is this what 'gap detect' in EACs doing?

I use FLAC and a few LAME mp3s in foobar, so it is moot to me.

 

[pata2001]

Quote:

Originally Posted by oicdn /img/forum/go_quote.gif 1st Gen Nano has gapless. You have to configure it in iTunes oddly enough and check the box that says "this is part of a gapless album" and when the entire album is on my Nano...it's gapless.... Otherwise, the songs aren't gapless unless you check that box for EVERY song you're putting on your iPod...

No, 1st gen nano is NOT gapless capable. I have it, and it's not gapless capable.

As others and I have pointed, the "part of gapless album" check box is NOT required for gapless playback. It only disables crossfade for those tracks.

5G iPod is not gapless out of the box, it requires the updated firmware (I think version 1.2 onwards).