Skip to main content ↑ ↓

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Worried about my iTunes libary/music files after iTunes/iPod issues. (Read 4780 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Worried about my iTunes libary/music files after iTunes/iPod issues.

Hi all.

Yesterday I wanted to find out if I had any missing/lost file entry's in my iTunes library so I used the "tag all" method i.e Selecting all tracks and applying a change to all track tags, in this case BPM to help show up bad file links.
After doing this and seeing no issues I then plugged in my iPod Classic for a resync . During this sync iTunes crashed with the "This application has to close" error. At this point I updated iTunes to the latest version before continuingin an effort to help the situation and started up iTunes again restoring the iPod in case the failed sync had broke something on the iPod. Once this restore and re-sync was completed(with no crashes) I attempted to play a recently added mp3 file that I had played on the iPod and computer successfully a few days earlier and when I did it didn't play kicking me back to the playlist almost instantly. Strangely this file plays fine on the PC, and a subsequent re-downloading of the MP3 exhibits the same behaviour.

I have some questions which if I am able to get some answers to would help ease my concerns greatly as I am am really worried about the integrity of my iTunes library as whole -

How likely is changing many thousands of ID3 tags at once in iTunes to cause files to be broken, given that there were no errors or crashes during this part of events ?

Could a Application closing crash during syncing be as a result of broken files, or would iTunes give a specific error for this under most circumstances and not crash ? Also could a crash during sync damage source files on the computer ?

Is there any way of "sanity checking" many thousands of AAC files (both protected and unprotected) in one go so i can at least make sure the basic file structure is intact ? I have no idea if this is the right place to ask such things or if anyone is able to help but i recalled these forums being very helpful tro read a few years ago when I needed information on codec comparisons and the like...

Worried about my iTunes libary/music files after iTunes/iPod issues.

Reply #1 –
I appreciate your inquiry but the truth is it seems AAC files have no internal CRC or MD5 to check integrity of the audio stream. You think since it's a new generation encoding system it would've been a given for that sort of thing but apparently the developers are idiots or never had corrupt music files. I have everything in FLAC which contains checksum info for verification later using something like Vuplayer AudioTester. MP3 files can even make use of the highly sophisticated MP3 Diags or mp3val to verify integrity. foobar2000 has a plugin to verify integrity of audio but I'm unsure how it works with AAC files (just merely decodes them?) that would be your best bet.

I can tell you a few things, iTunes uses a non-standard tagging system for mp3 files which i discovered long ago transferring files over to my Linux system. It was mostly unable to read id3 tags if I'd added fields using iTunes, it didn't matter what program I tried. Hence my reason for switching to Ubuntu and using puddletag and MusicBrainz Picard to tag everything. Good luck!

Worried about my iTunes libary/music files after iTunes/iPod issues.

Reply #2 –
Wow, I don't know where to begin after reading the previous post.  iTunes reads and writes ID3 tag information with mp3 files just fine (it can even convert between different versions of ID3 tags).  It only uses custom tagging (information added to a database file and then associated with the appropriate audio files) if information such as song rating, play count, album art downloaded from the iTunes Store, and a few other things are added.  Standard information such as genre, artist, album, year of release, track number, disc number, and even comments are all part of the ID3 standard and iTunes works with them.

Now, to answer the OP's questions:

1) Editing thousands of ID tags (remember that AAC files don't use ID3, that is only reserved for mp3 files in iTunes) could have caused iTunes to hang.  It is an extreme resource hog under Windows and I have experienced it crashing while doing much less than that.  However, the only time it would crash is when the tags are actually being edited.  The crash that you experienced was likely due to something completely different.  There are 1.2345X100^100 reasons why iTunes could have crashed and any issues arising from editing the track tags would have happened during the actual process.

2)  No, iTunes being forced to close would not damage the source files in any way.  Their ID tags might be missing information (only if iTunes was force closed while it was actually editing the track tags) but the physical files will be in tact.  In my almost 8 years of using iTunes, I have never come across a situation where it damaged the actual audio files.  The track tags?  A few times, iTunes has freaked out on me and continues to do so but the absolute worst that has ever happened is that it either didn't completely edit a track tag or it inserted some strange rating that is essentially 5 hallowed out stars.

3)  Your problematic mp3 file is likely the result of a bad sync.  The simplest solution would be to just restore the iPod again and re-sync the content.  On a side note, the ability of iTunes (or any other program for that matter) to playback content does not guarantee iPod compatibility.  For example, I have a 1080p 40Mbps mpeg-4 AVC video that iTunes can playback without issues yet there isn't a single iPod, iPad, or iPhone out there that could actually play it.  I have also come across many corrupt mp3 files in my time (mainly during my bad IRC days) that iTunes could play yet my iPods couldn't.

4)  I believe foobar2000 can check the integrity of AAC files but don't quote me on that.  Despite Sam's negativity towards AAC and its idiot developers, I am sure there are many ways to check if the files are fully in tact.  There are a bunch of AAC tools out there and I know that foobar2000 has a few.  I suggest you download that program (it is free), import your AAC files, and see what you can't do.  Sorry I can't be of more help on this front as I have never had to check my AAC files.

Worried about my iTunes libary/music files after iTunes/iPod issues.

Reply #3 –
iTunes writes ID3v2.4 frames with ID3v2.3-like frame sizes, which results in corrupt tags. Most ID3 implementations have to use heuristics (e.g. Mutagen, TagLib, libtunepimp, XMMS2, Jaudiotagger, etc.) to detect such broken tags. If you write a 100% spec-compliant ID3v2.4 parser (most linux players) it won't be able to read iTunes-written tags.
 

Worried about my iTunes libary/music files after iTunes/iPod issues.

Reply #4 –
Quote from: SamDeRe81 on
iTunes writes ID3v2.4 frames with ID3v2.3-like frame sizes, which results in corrupt tags.


Wasn't this already fixed?  Can someone confirm it's still a bug?
referring to 2.4 frame length issues (if this is the same issue):
http://id3.org/iTunes says "this issue was fixed about iTunes 8."

(Also, I had read that id3v2.3 was the most widely accepted standard, not 2.4.)