'Remember Playback Position' DOES NOT WORK

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david1951

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OK, this is a revised post, more clearly identified.

Here's what I'm getting on my 4G color iPod, with iTunes 5 installed on my PC.

* An mp3 file (which opens perfectly in other applications, I'm sure there's nothing wrong with it).
* About 4 hours long (3rd part of a book).
* Used the 'Remember playback position' checkbox in iTunes.
* Moved file to iPod.
* Double-checked that the 'Remember...' option still set on the file on iPod.

It REFUSES to do anything except play from the beginning, even though it is marked as 'Remember playback position', and REGARDLESS of any scrolling through the file using fast forward and reverse, whether I click the centre button first or not.

What is more bizarre is that the progress/time elapsed indicator shows correct (?) time elapsed. The display might show, for example, 2 hours 5 minutes, and keeps on incrementing correctly... BUT THE FILE IS PLAYING FROM THE BEGINNING.

If I play it through from the beginning, then pause and then play some other file, then come back: the progress bar shows the correct time for where I left off. BUT THE FILE STARTS PLAYING FROM THE BEGINNING! With the time indicator incrementing half way through the file.

I'm getting VERY sick of hearing the first part of this file again and again.

The M4B and M4A versions of this file cause the lock-up.

What do I do? Sell my iPod and go back to listening to Audio CDs?
 
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moriond

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David,

(Comment I was trying to reply to your earlier posts, now deleted. Hope this still applies!)

I haven't seen anything quite like your reports (which, I must admit, have a certain lurid fascination mixed within the horror ;)), but as I understand it, these involve audiobook files which were created in a previous version of iTunes(?) and which are well behaved when played under iTunes, but exhibit these bizarre timing offsets (only) when played on your 4G color iPod when made bookmarkable with the new checkbox option under iTunes 5? I'm asking because there have been some odd reports about files that play weirdly outside of iTunes.

Here's an example reported in MacFixIt. Again, because the link is only readable by non-subscribers for a day or so, I'll quote the account. This is another example of odd behavior found under iTunes 5, and is prefaced as "Jason Smalley reports an issue where AAC tracks encoded with iTunes do not play properly in other applications -- in particular they stop about three-quarters of the way through."

Reported 2005-09-16 by Jason Smalley to MacFixIt regarding iTunes 5
"I have a crazy 'bug' for lack of a better word. CD's and books encoded with Quicktime 7.0.1 and iTunes 4.9 play just fine in both iTunes and all Quicktime aware applications (Quicktime Player, iMovie, etc).

Now with iTunes 5.0 and Quicktime 7.0.2 things are completely messed up. Books and CDs encoded with the terrible twosome play fine in iTunes, but in all other Quicktime aware applications, they only play to 72% of their total time.

For example, A chapter from an audiobook (ripped as a single track with Join CD) plays for 48:09 in iTunes as one would expect, but if you play it in either Quicktime Player or iMovie, it only plays for the first 34:56. All subsequent data is gone. This gives a value of 72.5511% of original.

You are probably saying what is with this 72% number. I really don't know, but I checked it with another file. That other file should play for 22:16 but in all other apps besides iTunes, it only plays the first 16:09 resulting in only the first 72.5299% of the file. How weird is it that in both cases only the first 72.5% of the file would be played outside of iTunes? I think it is weird.

Furthermore, all files encoded prior to iTunes 5.0 and Quicktime 7.0.2 play fine both in and out of iTunes."
There are definitely some other instances of AAC files created under iTunes 5.0 and Quicktime 7.0.2 behaving oddly. On Macs, audiobooks merged and Chapterized with Doug Adams' Join Together AppleScript (which requires QuickTime Pro) only play up through the first joined segment. These files play all the way through when they're left as movie files, which is the default output created after you've joined .m4a files with QuickTime Pro -- a movie file with only the audio track. However, if you covert this to a .m4a file, as you would for podcasts following Apple's instructions, and as you need to do if you want to use ChapterTool to add chapter markers, the files stop playing at the end of the first chapter. This is supposedly a temporary bug in iTunes 5.0 according to Doug Adams. If any Mac users are using iTunesJoin from 3am Coffee, a similar merging problem applies under iTunes 5.0, and they recommend that people stay with iTunes 4.9.

Excerpted from Doug Adam's AppleScripts for iTunes page 2005-9-14
Updated: Join Together 2.0[snipped]
As you may have read in my previous posts, iTunes 5 has trouble with files created with earlier versions of Join Together, whereby only the first of the joined files is recognized. I have been told to assume that this is a bug in iTunes 5, although this hasn't been completely confirmed. As a result, the script no longer uses the "Pass Through" Audio setting in QuickTime Pro, but enables you to select a specific bit rate. This increases the time it takes QTPro to export the final file, but it's a sure-thing that the final file will play correctly in iTunes 5.
The only other timing complaints that I've seen with the move to iTunes 5.0 have come from macintouch

Posted by Darren Scantlebury-Watson 2005-9-14
Maybe it's just my particular installation, but trying to convert to AAC gives variable results - some files work fine, others come out shortened (e.g. a track 3:24 long cut off at 1:20 for no discernible reason). Worst culprits seem to be VBR encoded MP3 source files, although the problem seems to be entirely random, and occurs when using the default 128kpbs setting and at other custom settings I have tried. Anyone else had a similar experience?
None of the above examples is iPod specific. I have seen some previous complaints of iPod playback times not being accurate in the Apple Discussion Forums, especially on the photo iPods (now called color iPods). The last time I looked at this in depth was for the forums post discussing whether mp3 coding of intermediate merged audiobook files could affect iPod freezing and skipping in playing back the final bookmarkable file. There were several examples of the Photo iPods being more finicky, and cutting off play before the end, but nothing like the time shifts that David is reporting with his checkboxed mp3 files.

Couple of questions: (1) Were the mp3 files created under iTunes 4.9? (2) If the files were in the library at the time the upgrade to iTunes 5.0 reorganized the file structure, could you do a test on a clean iTunes 5.0 library? That is, create a test account, set up a new iTunes library from the clean account, create the (same) merged mp3 file. Checkbox it, transfer it to your iPod and check whether it behaves in the same weird way. It's just possible that the iTunes Music Library Database.xml file got munged in the upgrade.

david1951 said:
What do I do? Sell my iPod and go back to listening to Audio CDs?
Well, I have a second, nice 3G iPod that works without these bookmarking problems.:) You could always go back to a 3G.

Edited to get the last line from cut and paste of the response to the previous, now deleted, post. And to add response to plaintive appeal.
 
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david1951

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moriond, sorry to have switched posts on you, but the previous thread wasn't descriptive of what was happening.

The MP3 file concerned was one I merged with MarkAble, but the source files that I merged had been ripped from Audio CD by iTunes 4.9.

I'm prepared to believe that maybe there is something odd about the merged file - blaming it on my merge process - though I can't imagine what. It opens and plays fine in Windows Media Player and Audacity. It also opens and plays fine in iTunes itself on the PC, which matches your reports of files being OK in iTunes but not on the iPod.

I'm currently using Audacity to split the file into 2 x 2 hour chunks, saved out as WAV, which I'll then re-encode to MP3 with iTunes without any merging.

I'm getting very frustrated trying to finish listening to this book!
 
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david1951

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Just a further report on this to complete the picture.

So far, I've been listening to the re-processed MP3 files without any problem. But I've had so many problems with this particular book I'm starting to think it's jinxed, so I won't breathe a sigh of relief until I've finished it. (For the record, it's "Keep Me Close" by Clare Francis, and a damn good read - when I can get the iPod to cooperate).

Which still leaves the open question - why was my iPod behaving so bizarrely with this file, which played fine in other applications? I'm prepared to believe there was something odd about the merge, but what? The MP3 file structure is pretty simple, really.
 

david1951

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And yet another update: I've now had a couple of other MarkAble users report the same, utterly bizarre behaviour. I'm going to do as scientific a study as I can of different MP3 files to see if I can figure out what causes the iPod to behave this way.
 

david1951

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Now here's the thing: the files I have been having trouble with have had the "PCST" frame added to the ID3 tag, so iTunes thinks they are podcasts and makes them bookmarkable.

I realise now that the current file I am having trouble with was NOT repeat NOT merged by MarkAble (it was cut from an Audacity recording). So MarkAble's merge function seems off the hook.

I took the very same file I've been having this bizarre behaviour with, used a hex editor and removed the PCST frame. Loaded it back into iTunes and onto the iPod, making it bookmarkable with the 'Remember playback position' checkbox.

This altered file plays perfectly normally and retains bookmark.

So.... does the bizarre behaviour happen with any podcast file? I can't see any difference between the files I have made and the ones iTunes has imported as podcasts.

Anyone out there reporting this kind of behaviour with 'real' podcasts?
 
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david1951

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OK, after doing some exhaustive testing of various variants of the same file, I can report that it's not, after all, the PCST (podcast) tag that seems to make the difference.

I believe it's to do with the 'Xing' header appended to variable bit rate (VBR) files (and some constant bit rate files). Fundamentally, the iPod really doesn't like these headers (though iTunes itself is fine) - at least not the headers which MarkAble is writing (though again, I've had the same problem with files which MarkAble didn't merge).

The iPod gets very confused with long VBR files and misjudges where the bookmark applies to, sometimes to the extent of losing the plot entirely and having to start playing from the start.

MarkAble now attaches an Xing header (which gives a preview of how many frames are in the file) when it merges, whether the merged files were VBR or CBR. Perhaps I'm constructing this wrongly, perhaps not (as I say, the problem has hit files MarkAble hasn't touched). In any case, the iPod doesn't like it, or calculates wrongly based on it, or something.

I'm still investigating. I'd like to try a VBR file which iTunes itself has created to see if the problem occurs there.
 

david1951

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OK, a couple more results. Firstly, the evil behaviour seems to hit any long VBR file on the iPod - I converted a WAV file to VBR MP3 using Lame.exe (nothing to do with MarkAble, therefore). And it exhibits the same behaviour on the iPod.

I've been adding an Xing header whether the file was CBR or VBR (perfectly legitimate to do this). Now I'm only going to do it if the file really is VBR - and warn people against VBR on the iPod. I'll put up a new version of MarkAble (1.3.5) in an hour or so.
 

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Xing header issue for mp3 tagging - (also, playing time issues and VBR files)

Hi David,

I think this issue came up in the New thread about audiobook freeze. Different conditions thread back at the end of July and beginning of August when we were trying to figure out why stripping mp3 tags might make playback more successful in converted AAC files.

Here's an excerpt from some of my comments about how mp3 tagging could play badly with the iPod. The link to the vbr-mp3-fix web page discusses the issue of Xing headers for iTunes, and the link in the quote excerpt will take you back to the middle of the relevant thread.
Excerpted from Aug 1, 2005 post by moriond
There may be problems with the way iTunes reads mp3 ID3 tags and then with the database information transferred to the iPod and used for playback. That's known to be problematic for variable bit rate mp3 files produced by other encorders that may get cut off (for example, see this vbr-mp3-fix web page).Such VBR files may also be associated with stability issues and skipping, even on older iPods (according to this Apple Discussions thread.
It's also known that there are stuttering problems in the 2G mini with mp3 files encoded with with LAME in place of iTunes as described in this Apple Discussion Forum thread(This is excerpted from a very long and detailed description of the problem for the 2G mini (vs 1G) and under what conditions it is seen -- main point for our thread is that the problems don't occur when the encoding was done with iTunes).

I can believe that removing all mp3 ID3 tags before conversion to AAC helps the stability of home-made bookmarking, but it's odd (though still plausible) that this should be true even for mp3 files encoded by iTunes.

I'm not sure what to conclude from all this, but mp3 tagging/encoding sources certainly can affect iPod playback, especially on the new models.
I think what you're currently finding is consistent with the problems other folks have reported.

P.S. One reason I put in all these links is that I'd have a hard time reconstructing all of this from memory. At least with a limited number of posts and the relevant references I can still find these things!;)
 

david1951

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moriond, thanks, as always, for these useful references.

It does seem to hang together in a pattern, doesn't it?

The interesting thing about what was happening with MarkAble-created files is that even though the files themselves were CBR, simply adding the Xing header (again, something which should be perfectly legitimate) throws off the iPod (but not iTunes).

Some further symptoms of files with this problem: even if the file appears to hold a bookmark and starts playing at a position into the file on the iPod, you can determine by direct comparison between the file playing in iTunes and the same file playing on the iPod that the iPod is getting the position wrong.

For example, if in iTunes I play the file at the 2 hour or 3 hour positions and note what is being said, then try the same on the iPod, the iPod gives a totally different position in the book (though whether it's earlier or later I didn't have the patience to determine). Ditto if you play the very last few seconds of each file! The iPod must be cutting it off early (since it can't do it late!).

I really don't think my MP3 files are badly constructed according to the standard. I think it's just that the iPod firmware stuffs up with long VBR files in general (and my addition of the Xing header to all MP3 files makes the iPod think they are VBR). I've now changed this in MarkAble 1.3.5, now on the iPodSoft web site. I'm adding the header now only to files I know are actually VBR.

I say 'long' because VBR music files don't seem to cause any grief (not that you are trying to bookmark them, of course).
 
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