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[lalittle]

6. NEW: iPods support gapless playback. (requires gapless compatible iPod and LAME (or other gapless friendly) MP3s)

I'm sorry to report that gapless playback still does not work on my iPod (5G.)  It has the same problem as before, which is a small "jump" forward at the transition where a small piece of the song is cut out.  While there is not always a "pop" at the seam (sometimes there is, sometimes there is not), I can clearly here that the beat does not continue seamlessly accross the transition, and sometimes there is an actual "gap" and/or "pop" as well.  This is the same problem I reported a while back, and I'd actually say that it "may" be slightly worse than before.

I did a full re-initialize and full re-sync.  I tested both with an encode from a little while back, and a new encode of the same album made last week.  All my encodes were done with the default MC encoder using VBR, and all of them used a version of LAME that supports gapless playback.  These same songs DO play back gaplessly when playing them on the same iPod using Rockbox.

I sent some files to JR a while back that demonstrated the issue, so if you still have these files you should be able to hear the problem.

Thanks,

Larry

[SwellGuy]

Larry,

I hear clicks, pops and gaps the first time I play the three sample tracks you sent us when I transfer them with iTunes, too. The next time I play them they are perfect. When I trasfer them with MC I see (hear) the exact same behavior. Our DB values are identical to the ones written by iTunes except that we include Sound Check values and they don't.

Try this: Try turn off sound check on the iPod and try playing the same files a second time and see if the clicks, pops and gaps disappear.

(We'll look into the sound check issue.)


Rick

iPod Video (5G) ver. 1.2.1
iTunes 7.0.2.16
MC 12.0.173

[lalittle]

Larry,

I hear clicks, pops and gaps the first time I play the three sample tracks you sent us when I transfer them with iTunes, too. The next time I play them they are perfect. When I trasfer them with MC I see (hear) the exact same behavior. Our DB values are identical to the ones written by iTunes except that we include Sound Check values and they don't.

Try this: Try turn off sound check on the iPod and try playing the same files a second time and see if the clicks, pops and gaps disappear.

(We'll look into the sound check issue.)


Rick

iPod Video (5G) ver. 1.2.1
iTunes 7.0.2.16
MC 12.0.173

Are you positive that you're not hearing the tiny "skip forward" issue?  The "problem" is not always an audible click, gap, or pop.  MOST of time the problem is a slight "skip" forward, where a VERY small piece of the song is cut off at the transition.  The effect is that even though there may not be any "click" or "gap," the beat is slightly corrupted at the seam.  This is not necessarily something you'd notice if you aren't familiar with the song, but if there is a steady beat across the transition and you are familiar with how it "should" sound, you can hear the problem.

Is it possible that you were only listenning for a "click," and therefore did not notice the slight "jump foward" where a small piece of the song was cut out?  I would bet that tests would show that some samples are being clipped at the seam, and the iPod is simply butting the two songs up against each other with the small piece missing.

Note that I have the luxury of testing Rockbox as well, and the same songs played back via Rockbox simply do NOT have this issue.  When played back via the native Apple firmware, on the other hand, I hear the problem.

Sound check is already turned off (I actually never have it on), so this is not the issue.

Regarding the "first time / second time" issue, my first thought is that this is simply a caching issue caused by jumping to the end of the song before the iPod has had a chance to cache it.  If you give the transition a little more run-up time (i.e. jump to a minute before the end of the first track), you might find that it plays gapless the first time when using iTunes.

That aside, even if the songs are completely cached in the iPod, I still hear the problem at the transition.

The bottom line is that with an MC sync on my 5G iPod (version 1.2.1), gapless playback still does not work correctly unless I install Rockbox on the iPod and play the same songs using the Rockbox firmware.

Thanks for any further testing/feedback on this,

Larry

[NickM]

I get the same (very small) gap using the iPod Nano - as this is not HDD based, I guess the question of caching is removed.
Just to make sure I have followed the right steps..

1. MC12.173, Help, Check for Updates to get the latest LAME - leave the default (AlexB) settings.
2. Flush Handheld cache and reinitialise iPod Nano
3. Rebuild content from APE's.

[lalittle]

I get the same (very small) gap using the iPod Nano - as this is not HDD based, I guess the question of caching is removed.
Just to make sure I have followed the right steps..

1. MC12.173, Help, Check for Updates to get the latest LAME - leave the default (AlexB) settings.
2. Flush Handheld cache and reinitialise iPod Nano
3. Rebuild content from APE's.

If you play the transition a few times in a row, do you hear what I've been calling the small "jump forward" at the transition?  In other words, what I'm hearing is not a "gap," but rather a small jump where a tiny piece of music is cut out, and the song "jumps foward" when the seam goes by.  I agree that it's a VERY small jump, but it's enough to hear, and on albums that are intended to be gapless, it's quite annoying.  I'm never sure if people actually mean "gap" when they use that word, or if they simply mean that they can hear a "problem" at the transition.

Note that I've tried three different LAME encoders settings:  --preset standard (from the previous MC versions), -V 2 --vbr-new (the new MC "High" setting), and -V 1 --vbr-new (between the new MC "High" and "Extreme.")  Gapless doesn't work with ANY of these using the native Apple firmware, but ALL of these play back completely gapless using the Rockbox firmware, so I can confirm that the iPod hardware is definitely "capable" of playing back totally gapless.

Thanks for your report,

Larry

[NickM]

Sorry Larry, I missed the subtlety of gap as opposed to trailing or leading edge being cut.  I will sit down in a quiet room, headphones and some continuous play albums.  Report later...

[Matt]

It would be helpful to try transferring the same MP3 files with iTunes to see if it's any better.  We think we're writing identical database values, so would expect identical results. (comparing RockBox firmware might not be a fair test)

[lalittle]

It would be helpful to try transferring the same MP3 files with iTunes to see if it's any better.  We think we're writing identical database values, so would expect identical results. (comparing RockBox firmware might not be a fair test)

I considered that, but I was hoping that if Rockbox could do it, so could MC regardless of what iTunes could or could not do.  So far, I've successfully avoided installing iTunes on any of my systems -- I just don't like iTunes or agree with some of Apple's practices, so I wanted to keep iTunes off the system if at ALL possible.  That said, I can't say whether or not iTunes has the same problems as MC in this regard.  I guess I was thinking (and hoping) that even if iTunes DID have the same issue, MC could solve it.  This wouldn't be the first time that MC provided an advantage over iTunes for synching iPods.

What I CAN say is that according to other reports -- both around the web and in the MC forums -- the consensus is that iTunes syncs on the iPod are in fact gapless.  "Coolblue" did a lot of detailed testing a while back with MC and iTunes syncs, and he posted that iTunes syncs were totally gapless.

Coolblue:  If you're reading this, perhaps you could post a report on any recent syncs you've done.

I may have to go ahead and install iTunes, however, just to test this.  I'd hate to go through all that, however, just to find out that iTunes does NOT have the issue, and that there in fact IS something different about what MC is doing.

If iTunes syncs DO in fact show the same problem, however, will it still be possible to have MC create "truly" gapless playback?  Rockbox confirmed that the hardware is capable of this, but I don't know if this implies the possibility of the Apple firmware having the same capability.

Thanks again for all the feedback on this,

Larry

[lalittle]

It would be helpful to try transferring the same MP3 files with iTunes to see if it's any better.  We think we're writing identical database values, so would expect identical results. (comparing RockBox firmware might not be a fair test)

Due to my schedule, I won't be able to test this for a couple weeks -- I just won't be around home long enough to do any sort of testing in this regard.  If anyone else has any information on whether or not iTunes is REALLY gapless or not -- i.e. whether or not the little "skip" at the transitions when listening on an iPod is unique to MC syncs or not -- please post your findings here.

Thanks,

Larry

[Magic_Randy]

I may have to go ahead and install iTunes, however, just to test this. 

Larry,

Don't you have to have iTunes to keep the firmware current?  Or do you just use Rockbox?

Randy

[lalittle]

Larry,

Don't you have to have iTunes to keep the firmware current?  Or do you just use Rockbox?

Randy

I actually just stop by an Apple Store (there are a couple near me) and let them update it.

Larry

[Magic_Randy]

I actually just stop by an Apple Store (there are a couple near me) and let them update it.

Larry

If everyone did that, maybe they would re-introduce the stand alone updater.

[bob]

If iTunes syncs DO in fact show the same problem, however, will it still be possible to have MC create "truly" gapless playback?  Rockbox confirmed that the hardware is capable of this, but I don't know if this implies the possibility of the Apple firmware having the same capability.
Larry

One REALLY major difference between rockbox and mc/itunes is that rockbox is NOT using the second processor for mp3 decoding (at least it wasn't last time I tried rockbox with a 4th gen ipod) hence the greater power draw when using rockbox . Anyway, this means that on the ipod with rockbox there is a completely different algorithm for playback!

So you really cannot compare rockbox to mc/itunes. You need to compare mc TO itunes.

[lalittle]

So you really cannot compare rockbox to mc/itunes. You need to compare mc TO itunes.

My point was simply that as a unit, the iPod itself has the ability to do "completely" gapless playback, but this is really not the main issue here.

Given what I'm hearing at the moment, playback is most certainly not gapless with an MC sync, and I would think that a LOT more people would have reported this if it was also a problem with iTunes.  When people on the previous MC12 beta forum tested this several months ago, there WERE a few people that confirmed that while iTunes syncs played back gapless, MC syncs did not.  Keep in mind that at that time, MC syncs were "supposedly" capable of gapless playback as well.  Cut to several months later -- MC is once again "supposedly" able to do gapless iPod playback, and yet the EXACT same issue is present as before.

Without having tested iTunes yet, my best guess at this time is that there is still something amiss with MC syncs that are preventing gapless iPod playback from working correctly.  I admit that I cannot "know" this without testing an iTunes sync, but based on the current information, MC still seems like a likely culprit since the issue is the same as it was before.

I think the reasons we don't see more reports of this issue here are due to the limited number of people with access to this build, the fact that people have grown very accustomed to non-gapless playback on mp3 players in general, and the fact that most people don't listen to gapless albums these days.  When a more recent build is released to the regular MC12 forum, perhaps we can get some others to test and confirm this.  If nobody has tested this with an iTunes synch in a couple weeks, than I'll try it myself -- I should be in a position where I can do it at that point.

In the mean time, if anyone who has time to test this with albums from bands with gapless albums like Pink Floyd or older Genesis, please report here.

Thanks,

Larry

[lalittle]

Sorry Larry, I missed the subtlety of gap as opposed to trailing or leading edge being cut.  I will sit down in a quiet room, headphones and some continuous play albums.  Report later...

Thanks Nick -- anything you can report will be helpful.

Larry

[prod]

In the mean time, if anyone who has time to test this with albums from bands with gapless albums like Pink Floyd or older Genesis, please report here.

Just done a restore (w/iTunes), initialise and full sync (w/MC12.0.180) using iPod 5G 60gb; gapless works perfectly with all the albums I've tried - some Pink Floyd was in there somewhere, some Gatecrasher/Oakenfold/Underworld mix albums. No pops, clicks or other distractions.

[Matt]

Just done a restore (w/iTunes), initialise and full sync (w/MC12.0.180) using iPod 5G 60gb; gapless works perfectly with all the albums I've tried - some Pink Floyd was in there somewhere, some Gatecrasher/Oakenfold/Underworld mix albums. No pops, clicks or other distractions.

Thanks for letting us know.  That's great to hear.

[modelmaker]

No pops, clicks or other distractions.

Listening to: 'It Can Happen' from '90125' (1983) by 'Yes' on Media Center 12 

[Magic_Randy]

Let's see what Larry thinks.  He has the sensitive ear for this test.

[modelmaker]

Viva le Tabs!

[prod]

He has the sensitive ear for this test.

How awful, was he born with this condition?

[lalittle]

How awful, was he born with this condition?

Yes -- it's a curse.

Sorry I haven't posted lately -- I just got back from Bora Bora.

I'll give this a try tonight and report back.

Just out of curiosity, was anything changed since build 173 that could effect this?  I looked over the list of changes, but I didnt' see anything that seemed like it could have fixed this issue since 172, and 173 didnt' work for me.

prod - did you listen for the VERY slight "jump forward" at the transition?  I have a feeling that a lot of people might not notice this if they aren't familiar with the songs.  The issue I'm hearing is noticeable when a steady beat continues across the transition -- I can hear a slight "skip-step" where a tiny piece of the song is missing.  There is typically no "pop" or "click" -- it's just a matter of a single beat being slightly shorter when the seam goes by.

Thanks again,

Larry

[prod]

prod - did you listen for the VERY slight "jump forward" at the transition?  I have a feeling that a lot of people might not notice this if they aren't familiar with the songs.  The issue I'm hearing is noticeable when a steady beat continues across the transition -- I can hear a slight "skip-step" where a tiny piece of the song is missing.

Hm. Yep, I did listen for that. However, I've now found a song that's doing exactly what you mention. Seems this is a bit of rarity but definitely happens - the same file plays seamlessly and properly in MC. I'll sync the same album in iTunes and get back here with the result.

[lalittle]

Hm. Yep, I did listen for that. However, I've now found a song that's doing exactly what you mention. Seems this is a bit of rarity but definitely happens - the same file plays seamlessly and properly in MC. I'll sync the same album in iTunes and get back here with the result.

Thanks prod -- it really helps to have somebody else confirm the problem.  I find that I can hear it to some extent on any transition that I'm really familiar with, but sometimes it is more pronounced.  Thanks in advance for letting us know what you find out about the iTunes sync.

Larry

[prod]

OK, the results are in; and it's the exact same results with iTunes. With this one file I get a slight forward-skip. Infer from that what you will.

I'd re-rip and re-encode to see if that made any difference but the bulk of my CD collection is currently under my sister-in-law's bed 6,000 miles away (or at least I hope it is).

Details of the test;

1. Plug in & restore iPod w/iTunes
2. Eject iPod
3. Import offending album into iTunes
4. Set Gapless and Compilation to YES in iTunes for the imported album
5. Turn iPod settings Sound Check & Compilations ON
6. Plug in iPod, transfer imported album to iPod w/iTunes, eject iPod
7. Using headphones, skip to the end of each track and listen to transition.
8. Make cup of tea, strong, drop of milk, 1 teaspoon sugar
9. Plug in & restore iPod w/iTunes
10. Eject iPod
11. Turn iPod settings Sound Check & Compilations ON
12. Exit iTunes, stop & disable iPod service
13. Load up MC12.0.185, plug in & initialise iPod
14. Transfer album to iPod w/MC12.0.185, eject iPod
15. Using headphones, skip to the end of each track and listen to transition.

[lalittle]

OK, the results are in; and it's the exact same results with iTunes. With this one file I get a slight forward-skip. Infer from that what you will.

I'd be very interested to see if a re-encode solves this.  I've been searching other forums for information on this, and the overwhelming consensus is that gapless does work with iTunes syncs.  I was able to find, however, a post that reported having to re-rip the song in a more recent version of iTunes to get it to work.  Most people, however say that the transitions are "smooth as butter" when synching with iTunes.  I would "think" that if this was an issue with iTunes as well, I'd be able to find some pattern to people complaining about this issue -- there are people out there a LOT more picky about this stuff than I am.  I cannot find any such pattern.

Thanks again for any and all feedback on this.

Larry

[lalittle]

In my reading on this issue, I'm starting to wonder if the issue could be due to differences in the way the lame encoder words vs the iTunes encoder.  It seems pretty consistant that a small bit of the song is cut off at the transition (creating the very slight "skip forwards"), so I'm wondering if the problem is due to a math error -- i.e. that with lame encodes, the math that the iPod is using ends up cutting off a few too many samples.

Unfortunately, I just don't know enough about this to really dig into it.  All I know is that while there is no "gap" at the transition, it is definitely NOT a smooth transition like it is in MC, or like it is with Rockbox.

Larry

[prod]

There's bound to be differences in the way the encoders work - tho if Rockbox is playing your tunes OK, then I guess LAME is doing its job correctly. It also appears that MC is doing its job, in that the same results occur with it and iTunes. I'd say that the fault here lies with the iPod firmware - it's not reading LAME encoded files "properly". Possibly if I converted my album to AAC (thereby telling iTunes to re-encode my files) it would work as expected, but I've had enough messing with iPods for today.

[JimH]

If you think it's related to the MP3 encoding, you could try testing with the gogo encoder.

[lalittle]

If you think it's related to the MP3 encoding, you could try testing with the gogo encoder.

I hadn't heard of that.  I did some searching, and from what I can tell the gogo encoder is a "spin-off" of the LAME encoder.  Why do you think this encoder would help if it still uses the LAME encoder as it's base engine?

Thanks,

Larry

[Alex B]

GoGo is originally based on LAME 3.88. GoGo does not write the LAME header that contains the gapless decoding info. Only LAME 3.90 and newer can write this header. GoGo's only advantage over LAME is the encoding speed.

AFAIK, MC uses exclusively the LAME header info when it converts the gapless playback values to the format that is used in the iPod database. Also iTunes reads the LAME header info on import, but it converts the info automatically to its proprietary database format.

[lalittle]

GoGo is originally based on LAME 3.88. GoGo does not write the LAME header that contains the gapless decoding info. Only LAME 3.90 and newer can write this header. GoGo's only advantage over LAME is the encoding speed.

Forgive my confusion, but if that's the case, how could the gogo encoder possibly produce gapless results?

AFAIK, MC uses exclusively the LAME header info when it converts the gapless playback values to the format that is used in the iPod database. Also iTunes reads the LAME header info on import, but it converts the info automatically to its proprietary database format.

My theory is that the problem is occuring during this conversion process -- i.e. that when the Lame header info is converted to the proprietary iTunes database format, it results in a few too many samples being cut off, thereby producing the little "skip forward" at the transition.

Thanks,

Larry

[Alex B]

Forgive my confusion, but if that's the case, how could the gogo encoder possibly produce gapless results?

It does not produce gapless results. The files are like any other standard MP3 files that cannot be decoded gaplessly.

[lalittle]

It does not produce gapless results. The files are like any other standard MP3 files that cannot be decoded gaplessly.

In that case, I'm completely confused by Jim's previous post, i.e.

If you think it's related to the MP3 encoding, you could try testing with the gogo encoder.

Thanks for clarification,

Larry

[Alex B]

The difference is not documented and possibly Jim was not aware about this detail. Since GoGo is based on LAME it is quite logical to assume that it writes the LAME header.

So instead of GoGo some other LAME version should be used for testing if the currently used LAME version does something erroneously. However, I don't think that is the case. I have not seen any reports about LAME header problems.

[lalittle]

So instead of GoGo some other LAME version should be used for testing if the currently used LAME version does something erroneously. However, I don't think that is the case. I have not seen any reports about LAME header problems.

I don't think it's a LAME header problem.  I think it's more likely a problem with the way the LAME header info is converted to the gapless info that the iPod uses.

Larry

[lalittle]

Any further feedback on this?  It's really quite disappointing that LAME encoded songs are not playing back truly gapless on my iPods (it's "close," but it's not "gapless," which is frustrating when listening to Pink Floyd, Genesis, etc.)

My guess is that this has something to do with the way the LAME header info is converted to the iPod format.  Based on the previous reports in this thead, it appears that iTunes has the same problems with songs encoded in MC (i.e. LAME encoded songs.)  However, all the reports I've seen around the web also indicate that with songs encoded in iTunes and synched to the iPod DO play back perfectly gaplessly (just like MC playback of LAME encoded songs.)

I simply do not know enough about this to investigate any further, so I'm hoping that somebody more familiar with this subject can persue it a bit.  All I know is that my albums that require gapless playback still have little "jumps" at the transitions that do NOT occur when playing back these songs in MC, or when playing back on the iPod using Rockbox.  I therefore know that it IS possible to achieve gapless playback -- it's just not happening when synching LAME encoded songs at this time.

I really hope that this issue is not just left behind with the idea that the current "gapless" iPod playback via MC is "good enough."

Thanks for any further assistance with this,

Larry

[JimH]

...  it appears that iTunes has the same problems with songs encoded in MC (i.e. LAME encoded songs.) 

This sounds like an Apple problem.

We're not going to work on this anytime soon.

[lalittle]

This sounds like an Apple problem.

We're not going to work on this anytime soon.

Jim,

If you look at ALL the evidence (and not just the recent test by prod by itself), it does NOT sound like an Apple problem.  Tests results have already been posted showing that using iTunes for the whole process DOES result in proper gapless playback.  A user named "coolblue" did some extensive test on this issue last october.  Here are the findings from his post:

Ripping Software: iTunes; Upload Software: iTunes; Source: AAC; gaps evident: NO
Ripping Software: iTunes; Upload Software: iTunes: Source: MP3; gaps evident: NO
Ripping Software: MC12; Upload Software: iTunes: Source: MP3; gaps evident: YES
Ripping Software: MC12; Upload Software: MC12; Source: MP3; gaps evident: YES
Ripping Software: iTunes; Upload Software: MC12; Source: MP3; gaps evident: YES
Ripping Software: iTunes; Upload Software: MC12; Source: AAC; gaps evident: NA (did not upload properly, but that's another story).

Summary: When it's all internal to iTunes gapless playback works beautifully.

Regardless of what's been fixed in MC since then, one thing is clear from these tests; if you use iTunes for both ripping and synching, the problem does NOT occur, and you get proper gapless playback on the iPod.  This was proven several months ago, and there is no reason to dismiss these findings now.  As you can ALSO see from the results, as long as MC was ANYWHERE in the chain of ripping/synching, gapless playback did not work properly.

Just because LAME encodes still have the problem when synching with iTunes does NOT mean that this is Apple's fault since iTunes doesn't use the LAME encoder -- i.e. you can't blame Apple for gapless issues when you use a non-iTunes encoder.  Apple has no responsibility to make LAME encodes work with iPod syncs.

That said, I still believe that LAME synchs CAN be gapless on the iPod -- I just think that there is a problem when converting the LAME header info to the iPod's gapless info.  Everything seems to be pointing to this.  If I knew more about this, I would compare the iTunes header info to the LAME header info.  Unfortunately, this is WAY beyond my experience and I wouldn't know what to look for.

For some reason, we keep reverting back to square one with this issue.  Some time goes by, and everybody seems to forget the tests that have already been run.  Recently, prod synched a LAME encode with iTunes and it showed the same gapless problems as the MC sync.  The conclusion made from this was that this is therefore a problem with Apple and not with MC.  If you really look at the evidence, however, it does NOT point to Apple, but rather to something else (my guess is LAME encodes.)  When you look at all the combinations above, you can see that the one thing in common with the failures is the LAME encode.  This is the ONLY thing that all the failed tests have in common.  Some fixes in MC have been made since then, and it's now possible that songs ripped with iTunes will be gaples when synched with MC (this hasn't been tested yet.)  All we know for sure, however, is that LAME encodes STILL do not result in gapless playback regardless of whether MC or iTunes is used to sync.  This does NOT point to iTunes or the iPod as the probelm.

I personally consider this a high priority, but I understand and accept that JR might have other issues that they consider more important.  If this is the case, however, MC cannot claim "gapless playback" with iPod syncs.  There might not be an actual "gap" of silence between tracks, but the songs do NOT flow smoothly from one to the next, which is what "gapless" means in this arena.  iTunes encodes synched with iTunes ARE gapless, but MC encodes/synchs are NOT.

Thanks,

Larry

PS.  We never did hear back about the files that coolblue sent in.  Did these reveal anything?

[JimH]

We have no plans to work on this, Larry.  I'm locking the thread now.