I can’t always read iTunNorm comment using mp3Tag


#1

Hi. My OS is Windows 7 Pro_64 bit
I’ve 10.000 mp3 files created in the last five years:
. tagged with mp3Tag v.2.53 (Mpeg options: READ ID3v1 and ID3v2 checked; WRITE ID3v1, ID3v2, ID3v2.3 UTF-16 checked);
. analyzed with mp3Gain (only analyzed, NOT Normalized);
. imported in iTunes (either iTunes 8 or iTunes 10) with Sound Check option turned on.

The Volume adjustment has been always calculated by iTunes (Sound check on) and is satisfying for me.
The mp3Gain APE information has been already read and extracted in an Excel file, using mp3Tag: everything is OK.
Now, using mp3Tag, I exported also “iTunNorm” field and all the generic “Comment” fields in order to interpret the Check Sound info written by iTunes; and I realized that I’m three different situations:

  1. Many files have the Check Sound info written in a generic “Comment” field;
  2. Many other files have the Check Sound info written in a specific “iTunNorm comment” field;
  3. About 1000 files don’t have the Check Sound info written anywhere (neither in a generic Comment field, nor in the iTunNorm field).
    In this third situation, the Volume Adjustment is well calculated by iTunes but, using mp3Tag, I can’t see any meta-tag info concerning Check Sound.

Moreover: if I add a new mp3 file in iTunes (10) library, the Sound Check is well calculated (there is a coherent Volume Adjustment in iTunes Get-info), but, using mp3Tag, I can’t see any Check Sound info neither in a generic comment field, nor in the specific iTunNorm field.

My questions:
. any idea about why I can’t see the Check Sound info using mp3Tag in (1.000) of my (10.000) mp3 files?
. how can I found Check Sound info in these 1.000 files ? (it must be somewhere because iTunes Volume Adj has been well calculated)
. did iTunes 10 stop to use iTunNorm field to write Check Sound info in mp3 files?
. if “yes” where iTunes writes Check Sound info and how can I read and exported Check Sound info using mp3Tag (preferred) or any other software?

Thanks in advance for your replies


#2

Answers

1- It could be that you where using a version of iTunes which did not write these tags. I only can recall that where some problems with iTunes version 9
2- You are out of luck, as this information is coded into iTunes.itl (iTunes Library Files)
3- I am not sure if my iTunes (11) does it, but I always write the tag with Mp3tag (rg2sc function) after analyzing the volume with Foobar (not with mp3gain) as Foobar only writes id3 tags and doesn't change the files as Mp3gain does. After that I import the file into iTunes.

I use this action to convert the Foobar tags, to iTunes Norm

This one is for Mp3

Action: Format Value
Field: COMMENT ITUNNORM
Format String:
$IF(%COMMENT ITUNNORM%,%COMMENT ITUNNORM%, $rg2sc(%REPLAYGAIN_TRACK_GAIN%))

This one is for M4a

Action: Format Value
Field: ITUNNORM
Format String: $rg2sc(%REPLAYGAIN_TRACK_GAIN%)


#3

Thank you Mike_nl for your answers.
It's strange because I never used iTunes 9 and because some of my 1000 empty files have been imported either in iTunes 8 (that i'm sure wrote the tags) or in iTunes 10; so I don't think it's an iTunes problem.
It's a problem that I can't figure out ...
However, many thanks


#4

I am not sure if it's only iTunes 9, I did a test with iTunes 11

Got a Mp3, removed ALL TAGS (Also the ones under ALT+T)

Then wrote something in Artist- Title - Year and import this file into iTunes.


Found out that the volume has been adjusted


Loaded that file into Mp3tag and low and behold

No Additional info found (Comment ITUNNORM etc)


So it seems that iTunes is not writing this Tag anymore





#5

Thanks a lot for your test. It's exactly what I find with iTunes10.
But I made another test. I took an old mp3 file with info in iTunNorm (verified with mp3Tag). I modified the title using the option “Properties” of Windows Explorer. Then I imported it in mp3Tag and I realized that the field ITunNorm has been canceled, and the the identic info has been deplaced in “comment”. Moreover if I import this new file in iTunes, the adjustment volume is calculated differently (-4,6 dB in the original file, -8,8 dB in the new file modified with Windows Explorer).
What do you think it’s happened?
I'm more and more confused


#6

I did the same test and I can confirm the behavior you noticed. This is something very strange with Explorer. I never noticed this as I don't use Explorer to edit Tags but only use Mp3Tag.

Edit: */ I found a discussion on the Apple Forum about that older iTunes versions (6 ??) wrote the SoundCheck values in the Comments field. Maybe Explorer is stuck with this behavior ??

Link: https://discussions.apple.com/thread/259384...=0&tstart=0

This is my Procedure when I get a new Mp3

  1. Open the File with Mp3tag
  2. Clean Out all Unwanted Tags (Via Extended Tags)
  3. Fill in the right information (Lyrics, Album Art etc etc)
  4. Import the File into Foobar
  5. Do a Scan-per-file track gain, and write the values in the Mp3
  6. Open the file again in Mp3tag
  7. Convert the Foobar Values to iTunes Tags (See Post #2)
  8. Import the Mp3 into iTunes.
The reason why I use the Foobar ReplayGain function, is a) Does not changes the file internally, but only writes Tags, b ) I feel it's a bit more accurate then the "Sound Check" function from iTunes.

#7

Many thanks Mike, your confirmation is very usefull and reassuring for me.
Thank you also for your procedure, linear and clear.
I know the difference between ReplayGain and SoundCheck. I was just comparing the two situation to understand something more about SoundCheck when i fronted this unknown (to me) problem.
I'll carry on with other tests


#8

Hi. After other tests I found (with a very high probability):

  1. iTunes 10 don't write iTunNorm tag anymore in the file mp3.
  2. iTunes 10 and iTunes 8 use a different way to calculate Sound Check; Sound Check calculated with iTunes 10 is lower of about 0,75-1,25 dB in average against iTunes 8. But in some file the difference may be very high (3,5 dB for example).
  3. If you have an old library built using iTunes 8 and you update to iTunes 10, the old library is converted into the new format iTunes 10, but the old Sound Check (calculated with iTunes 8) doesn't change (no new calculation). So when you add new files to the library with iTunes 10, you'll have a discontinuity with the old files imported from iTunes 8 as far as Sound Check is concerned: the new files sound lower in average than the old ones.

In conclusion, it would be better to use an external method (ReplayGain) to calculate Sound Check, (or to reset and recalculate Sound Check of all files when you update to a new version of iTunes); but it's not clear to me how to import in iTunes 10 the Sound Check values calculated by an external method (no more iTunNorm tag !).
"Obviously" I didn't find anything about that in apple/support.
Any idea or comment ?


#9

You can't, if there is no iTunNorm tag then iTunes calculates its own Values, and I am not sure even when there is a "custom" iTunNorm tag if iTunes reads it.

As you know Apple sets its own standards and makes it very difficult to make changes to it.

But I have one suggestion for you which you could try, there is a program called iVolume (http://www.mani.de/en/ivolume/index.html) you can try that to see if it helps you. It's (IMHO) expensive for what it does, but you can try it out for free to see if it suits you.


#10

Thank you Mike. I don't want to use iVolume.
But do you know how iVolume works if there's not iTunNorm anymore ? May be it writes its info directly in Library itl file? I don't think so ...
It's for this reason that I doubt that iTunNorm still exists and is perhaps hidden somewhere (different name ?).
I can't imagine where to find info about that. I posted also in apple community but nobody answered me yet.
I'd like also to understand which is the best sound check calculation method: iTunes 8.2 or iTunes 10.6 ? If I understood that, I could try to reimport all mp3 files using only one version of iTunes; but I don't want to get wrong once more.
It' also strange that, among mp3Tag users, nobody claims for the iTunNorm lack in iTunes 10.

Thanks anyway


#11

Have you noticed that m4a still contains the iTunNorm but Mp3 don't. I write them both with the rg2sc function (see Post #2), but I have no idea if it has any effect.

What you could try, set replay-gain to a crazy value (like 108 db) and see what iTunes does, my guess iTunes ignores these and other values and calculates its own values and thus abiding it's own set standards

There used to be a program (Volume Logic) that normalized the volume on the fly, but a newer version of iTunes removed some features (which that program utilized) and thus made that program useless, and there hasn't been a solution since, and the only thing left is "SoundCheck" / ReplayGain.

(Note: this was for an old version of iTunes (Last version was compatible with iTunes 7)

Maybe this could serve as an alternative (however I haven't tried it)
http://www.claessonedwards.com/index.php?o...&Itemid=135

http://www.claessonedwards.com/index.php?o...8&Itemid=90


#12

Thank you Mike !