HydrogenAudio

Lossy Audio Compression => AAC => AAC - General => Topic started by: brainstewx on 2009-11-27 02:41:27

Title: iTunes AAC caps the volume
Post by: brainstewx on 2009-11-27 02:41:27
iTunes 9 AAC is awful. No matter how loud the song is on your computer, or how loud you raise the volume with mp3gain, the volume will be capped when you play it on your iPod. I had to redo all my AAC's with Nero.

What a complete waste of time.

Stay away.
Title: iTunes AAC caps the volume
Post by: kornchild2002 on 2009-11-27 03:04:18
Do you have a European iPod model or some type of volume cap set in place by iTunes for your iPod?

The iTunes AAC does not cap the volume.  Sorry but that is incorrect.  I can adjust a track's volume (encoded with iTunes 9 and the latest QuickTime) up beyond -105dB.  It will clip when played on my computer and it will clip when played on my iPod.  I have experienced this for the past 6 years when it comes to iTunes AAC, iTunes, and my iPod.  European iPod models have a strict volume cap that is set in place due to the laws over there.  I am not sure what the volume level is but people have informed the that it is rather low.  I have also heard mixed messages when it comes to increasing song volume in that it doesn't do anything (though some people report that it solves their problem).  Either way, it is the iPod itself that implements the volume cap; not iTunes or iTunes AAC.
Title: iTunes AAC caps the volume
Post by: A_Man_Eating_Duck on 2009-11-27 03:04:26
is soundcheck enabled?
Title: iTunes AAC caps the volume
Post by: brainstewx on 2009-11-27 03:59:09
Quote
The iTunes AAC does not cap the volume. Sorry but that is incorrect. ... Either way, it is the iPod itself that implements the volume cap; not iTunes or iTunes AAC.


After encoding the same uncompressed file to Nero AAC, Lame MP3, and iTunes AAC, the iTunes AAC sounds about 6 decibels lower than the others (including the uncompressed one).

No, I'm not European and neither is my iPod, we are American. On my computer they all play at the same volume, however.

I can only conclude you have not tested this properly.

EDIT: On top of this, I have just done it again to make sure, this time with Weezer's song Buddy Holly. I tested the WAV, FAAC, Nero, LAME, and iTunes 9, and all were the same volume on my iPod except the iTunes 9 AAC which was substantially lower.
Title: iTunes AAC caps the volume
Post by: Manusnake on 2009-11-30 22:53:02
iTunes 9 AAC is awful. No matter how loud the song is on your computer, or how loud you raise the volume with mp3gain, the volume will be capped when you play it on your iPod. I had to redo all my AAC's with Nero.

What a complete waste of time.

Stay away.


Did you even think that you could be doing something wrong? I mean, you're so aggressive! Calm down!

iTunes doesn't put cap on AAC on encoding, but it does with the soundcheck on importing, and thus puts it on your iPod.
However, with mine (iTunes 9.0.2), the sound level I get is very good, and actually soundcheck is a bless for continuity. If you want to blow your hears, uncheck soundcheck and when importing your AACs file. Since iTunes write the info in the aac's tag while importing, the already soundchecked files will stay that way if played on iTunes or any given iPod. Sorry, you should have checked before doing this and then yelling against iTunes...

BtW, using Nero AAC on PC is a good idea since it is more configurable than iTunes (and use XLD on Mac).
Title: iTunes AAC caps the volume
Post by: brainstewx on 2009-12-01 02:55:31
My soundcheck is off and has always been off.

I'm telling you they put something in the AAC file it encodes. It will play back normally in iTunes, but when you're listening to your iPod it's going to be lower than an AAC or MP3 encoded with something else.
Title: iTunes AAC caps the volume
Post by: kornchild2002 on 2009-12-01 03:25:57
After encoding the same uncompressed file to Nero AAC, Lame MP3, and iTunes AAC, the iTunes AAC sounds about 6 decibels lower than the others (including the uncompressed one).


Did you actually measure this or are you guessing?  In other words, did you actually measure a 6 dB difference or did you pull that number out of thin air?

I can only conclude you have not tested this properly.


I guess not.  Using the iTunes AAC encoder for 6 years accounts for zero experience, knowledge, or test results.  You always know what happens when you assume something.

EDIT: On top of this, I have just done it again to make sure, this time with Weezer's song Buddy Holly. I tested the WAV, FAAC, Nero, LAME, and iTunes 9, and all were the same volume on my iPod except the iTunes 9 AAC which was substantially lower.


Was this a blind test with your iPod or was it sighted?  How did you conduct the test?  Did you actually measure your iPod's output?  Why are you so aggressive about being correct when you supplied us with (literally) nothing?

I don't mean to sound rude (unlike another post you made) but you gave us nothing to work with.  Sighted tests are flawed (as has been covered ad nauseum here at hydrogenaudio) and there really is no way of verifying your results other than measuring your iPod's output.  I have hundreds of tracks encoded with the latest version of iTunes and QuickTime.  They play at the same volume as Nero AAC and Lame mp3 files.  I have measured the output and conducted the blind tests (as blind as they could be with someone switching between tracks without me knowing the order).
Title: iTunes AAC caps the volume
Post by: brainstewx on 2009-12-01 04:51:35
 So tell us, how did you 'measure' the output from your iPod? That's assuming I believe you (I don't).

It's so painfully obvious that it's lower in volume, it's like picking out the green apple among the dozen red ones. These are just the facts, and what you're doing is an argument from ignorance. You can try to poke holes wherever you want, but the bottom line is I tested this, you haven't.

As for my rudeness, I frequent a politics board where we all talk like this. I'll try to control it.
Title: iTunes AAC caps the volume
Post by: ZinCh on 2009-12-01 08:46:17
have you tried to demux/remux m4a file, and change volume with aacgain?
Title: iTunes AAC caps the volume
Post by: Zarggg on 2009-12-01 15:51:38
brainstewx, please show us your data that empirically shows a 6dB difference.
Title: iTunes AAC caps the volume
Post by: kornchild2002 on 2009-12-01 17:18:15
So tell us, how did you 'measure' the output from your iPod? That's assuming I believe you (I don't).


Easy.  I simply hooked my iPod up to my PC's audio input (through a sound card), recorded the iPod's outout, and then compared the results.  Tracks that I have gained down to -89 dB played at -89 dB while other tracks played at higher volumes (the ones that I have not gained yet).

At least I took the time to measure something other than making statements without any merit.  The bottom line is that I have actually tested different files and measured my iPod's output.  You have not.  You can continue to try to poke holes in my methods but measurements don't lie.  Additionally, you seem to be the only one experiencing this problem.  Members of hydrogenaudio would have noticed this long ago (back when iTunes 9 was first released) if there was actually a problem.  Again, measure your iPod's output showing that 6 dB difference.  Otherwise your claims are nothing more than hot air.

hydrogenaudio is a place that prides itself on blind testing and measurement.  Otherwise anyone can come here, bash lossy audio, praise PCM WAV, and not give any reasoning behind this.  Other people can come here, claim that the audio plays at a different volume, and not provide anything else.  Claims needs to be backed up, that is part of the terms of service here at hydrogenaudio.
Title: iTunes AAC caps the volume
Post by: brainstewx on 2009-12-02 01:34:23
Ah I knew if I hung in long enough I would find out where you went wrong. You admitted you gained them down to 89db, which if that's true you wouldn't have noticed the volume cap or maybe you're already under it.

The several sound files I tested were all naturally 97db - 100db. What you should have done to properly test is to gain the files up with aacgain and see if you can raise the volume as high as non-iTunes AAC files.

You did not properly test this.

I'll give my 'data' later.
Title: iTunes AAC caps the volume
Post by: brainstewx on 2010-01-14 08:02:16
The issue with Apple has been resolved.

The volumes are now consistent with the volume outputs of other encoders.
Title: iTunes AAC caps the volume
Post by: Silversight on 2010-01-14 08:31:05
An explanation would be nice. What exactly was the problem, and how did it get resolved? Maybe others have similar issues.
Title: iTunes AAC caps the volume
Post by: loophole on 2010-01-14 09:35:21
I'm so sorry I've made a mistake...
I'm so sorry I've made a mistake...
I'm so sorry I've made a mistake...

I'm so sorry, but my wife has made a mistake!

I don't know how she did it! But she did! She's made a complete pudding of the whole thing as usual, it will be perfectly alright for you to stay I've sorted it all out but you know what women are like they've got one brain between the lot of them, well not all of them I mean some of them have so please do stay, and see you all later on. Thankyou so much.
Title: iTunes AAC caps the volume
Post by: LCtheDJ on 2010-01-14 20:13:45
The issue with Apple has been resolved.

The volumes are now consistent with the volume outputs of other encoders.


Could you please post the solution?

I have also observed the same.

I have encoded a file with iTunes and with Nero; decode both to wav and compare the two wav files. The iTune decoded wav has a lower max volume than the Nero decoded wav. This is clearly seen with both wav files loaded in a sound editor.
Title: Re: iTunes AAC caps the volume
Post by: brainstewx on 2016-08-16 04:14:14
The issue with Apple has been resolved.

The volumes are now consistent with the volume outputs of other encoders.

Could you please post the solution?

I have also observed the same.

I have encoded a file with iTunes and with Nero; decode both to wav and compare the two wav files. The iTune decoded wav has a lower max volume than the Nero decoded wav. This is clearly seen with both wav files loaded in a sound editor.
Sorry that I have not checked back here in years. At the time I said the issue was resolved, but it wasn't actually 'resolved' per se.

The poster that said this had the solution:

Quote
have you tried to demux/remux m4a file, and change volume with aacgain?
I extracted the raw AAC with MP4Box, and then used MP4Box to put the raw AAC back in an mp4 container, and the volume was back to normal. The process wiped whatever iTunes was doing to cap the volume. However, the downside is that this process also wipes away the album cover, song tags, etc.

So, even though it is possible to undo the volume cap, it is too much effort to bother with. I have simply gone back to using MP3.
Title: Re: iTunes AAC caps the volume
Post by: kode54 on 2016-08-16 06:26:44
Have you tried ReplayGain scanning the files with foobar2000, or editing the RG values manually, then applying them to SoundCheck tags?
Title: Re: iTunes AAC caps the volume
Post by: brainstewx on 2016-08-17 03:12:35
Have you tried ReplayGain scanning the files with foobar2000, or editing the RG values manually, then applying them to SoundCheck tags?
Not with Foobar2000, no. I was scanning with AACgain and using it to apply about a 97.5 db average for my mp4s, which I was encoding with the Nero, FAAC, and iTunes encoders. Playback in iTunes would be as loud as expected, but playback on an iPod would be much quieter, but only for the mp4s encoded with iTunes. It was as if what I had done with AACgain did not affect those files. Another poster accused me of doing sighted tests, but I could pick out the iTunes-encoded mp4s blindly every time.

I must say, I think it is no longer an issue. I tried the encoder on iTunes 12 just now. I AACgained/MP3gained two different files (iTunes AAC and LAME mp3) up to an obnoxious 100db, and both were equally loud and clippy on the iPod, so it seems Apple has fixed the problem some time in the last seven years.
Title: Re: iTunes AAC caps the volume
Post by: kode54 on 2016-08-18 21:03:28
Your iTunes encoded files would be quieter or louder or different, depending on how the SoundCheck tags were written to them by iTunes when they were encoded. Those tags would either need to be removed before syncing with the iPod, or rewritten with the newly AACgain adjusted files.