How does iTunes Match modify your music tracks?

randian

macrumors 6502a
Original poster
Jan 15, 2014
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I noticed that after buying iTunes Match and letting it do its thing, every track in my iTunes Library, other than tracks it refused to match because they were too big, now has a last modified time of today. This is disturbing, and it's not clear what iTunes changed in them. So, what did iTunes do to them? Munge my metadata? Change the artwork? God forbid, change the music track itself?
 

Julien

macrumors G4
Jun 30, 2007
11,282
4,265
Atlanta
First and foremost you should have a backup of your music (and everything else too). So no matter what happens you are covered.

Second it is usually just metadata and in most cases just the modification date changed since the file was scanned. The next most likely thing is artwork (which is metadata).
 
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randian

macrumors 6502a
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Jan 15, 2014
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Second it is usually just metadata and in most cases just the modification date changed since the file was scanned. The next most likely thing is artwork (which is metadata).
Yes, I do have a backup, but at some point I have to backup the modified tracks and likely overwrite the previous backup. It would be really annoying if iTunes replaced my artwork, I have a lot of high-res album covers and I'd hate to have them replaced without warning by iTunes. There's nothing in Apple's description of what iTunes Match does that suggests a modification like artwork replacement can happen.
 

Julien

macrumors G4
Jun 30, 2007
11,282
4,265
Atlanta
Yes, I do have a backup, but at some point I have to backup the modified tracks and likely overwrite the previous backup. It would be really annoying if iTunes replaced my artwork, I have a lot of high-res album covers and I'd hate to have them replaced without warning by iTunes. There's nothing in Apple's description of what iTunes Match does that suggests a modification like artwork replacement can happen.
It shouldn't replace the artwork. However it is best to buy a cheep (if you don't have one) USB drive and do a 'permanent' backup of only your Library.
 

randian

macrumors 6502a
Original poster
Jan 15, 2014
665
204
It shouldn't replace the artwork. However it is best to buy a cheep (if you don't have one) USB drive and do a 'permanent' backup of only your Library.
Shouldn't or doesn't? Too many lossless and high-res tracks to fit on a USB drive. I use external hard drives as backup.

If the only thing iTunes Match changed was adding the matched/not matched indicator to the tracks then I'm ok.
 

randian

macrumors 6502a
Original poster
Jan 15, 2014
665
204
Actually it will Match them to a 256kbps AAC iTunes/Apple Music copy or if no match available will make a 256kbps AAC copy and upload.
Unfortunately iTunes Match won't match or transcode a 24/96 or 24/192 track because it's too big. I understand why Match rejects long tracks, but the size limit is just plain nonsense. A 5 minute track transcoded from 24/192 lossless to 256k AAC takes up no more space on Apple's servers than one transcoded from 16/44 lossless. If it's matched rather than transcoded then of course it's not just the same size, it's the same shared track.
 

Julien

macrumors G4
Jun 30, 2007
11,282
4,265
Atlanta
Unfortunately iTunes Match won't match or transcode a 24/96 or 24/192 track because it's too big. I understand why Match rejects long tracks, but the size limit is just plain nonsense. A 5 minute track transcoded from 24/192 lossless to 256k AAC takes up no more space on Apple's servers than one transcoded from 16/44 lossless. If it's matched rather than transcoded then of course it's not just the same size, it's the same shared track.
What format are they in (ALAC)? Strange that if iTunes will play them it seems Match would support them. Also here is a workaround.

Make a Smart Playlist and sort by Sampling Rate or Bit Rate. If by Sampling Rate it would require 2 Playlists, one for 96 and one for 128. Then highlight that Playlist's tracks and convert them to 256 kbps AAC. This will make a copy. After matching you can delete the copies.
 

randian

macrumors 6502a
Original poster
Jan 15, 2014
665
204
What format are they in (ALAC)? Strange that if iTunes will play them it seems Match would support them. Also here is a workaround.
Yes, they're ALAC format. If you select "convert to AAC" it won't delete the original tracks? Does iTunes Match run automatically once the AAC tracks have been created? Won't deleting the new 256k tracks remove them from iTunes Match?
 

Julien

macrumors G4
Jun 30, 2007
11,282
4,265
Atlanta
Yes, they're ALAC format. If you select "convert to AAC" it won't delete the original tracks? Does iTunes Match run automatically once the AAC tracks have been created? Won't deleting the new 256k tracks remove them from iTunes Match?
It will make a 256kbps AAC copy and not delete the original. Convert is somewhat of a misnomer. Not sure if it will auto scan but but I think you can force it to scan by Files> Library> Update Match (or what ever it says). I don't have Match anymore so not 100% positive.
 

Rigby

macrumors 603
Aug 5, 2008
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San Jose, CA
Unfortunately iTunes Match won't match or transcode a 24/96 or 24/192 track because it's too big.
I don't think it has to do with the size. I have some 24/96 stereo tracks in ALAC format that are well below the maximum upload size (200MB) and still have the iCloud status "ineligible".
 

randian

macrumors 6502a
Original poster
Jan 15, 2014
665
204
I don't think it has to do with the size. I have some 24/96 stereo tracks in ALAC format that are well below the maximum upload size (200MB) and still have the iCloud status "ineligible".
It's not really an "upload" limit then, since transcoding a 24/96 track to 256k AAC will make something a lot smaller than 200MB.

If I create 256k AAC copies of my 24/96+ tracks to get them into iTunes Match, and then delete them, would they overwrite my high-res originals were I to redownload them in the future?
 

Julien

macrumors G4
Jun 30, 2007
11,282
4,265
Atlanta
...If I create 256k AAC copies of my 24/96+ tracks to get them into iTunes Match, and then delete them, would they overwrite my high-res originals were I to redownload them in the future?
ANY original file you delete will be deleted and gone. If you download the track from Match you will get a Match 256kbps file/track since Match doesn't have your original file/track for you to download. You should NEVER delete your originals unless you have a copy and are deleting to save space on your drive (like a small SSD).

EDIT: Missread your post. See Rigby's answer.
 

Rigby

macrumors 603
Aug 5, 2008
5,198
5,226
San Jose, CA
It's not really an "upload" limit then, since transcoding a 24/96 track to 256k AAC will make something a lot smaller than 200MB.
What I'm saying is that even in their original form these files are well below the limit, so that's obviously not the reason why iTunes Match considers them ineligible. It probably doesn't like sampling rates other than 44.1kHz.
If I create 256k AAC copies of my 24/96+ tracks to get them into iTunes Match, and then delete them, would they overwrite my high-res originals were I to redownload them in the future?
No, because the converted AAC copies will be separate songs in your iTunes library.
 

randian

macrumors 6502a
Original poster
Jan 15, 2014
665
204
It probably doesn't like sampling rates other than 44.1kHz. No, because the converted AAC copies will be separate songs in your iTunes library.
My 24/48 tracks got matched. That's probably the limit. Glad the AAC tracks are separate, but they quite annoyingly clutter my track listings.
 
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