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Topic: How can I use the AAC-VBR encoder of QT7? (Read 13006 times) previous topic - next topic
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How can I use the AAC-VBR encoder of QT7?

So, I installed MacOS X 10.4 "Tiger" and the new QuickTime 7.0 with a Pro license. How do I use the AAC-VBR encoder? I opened an audio track from an audio CD and then selected the "Export" menu option. Then I chose the MPEG-4 format and at the audio tab I can only choose the AAC-LC constant bitrate option while the AAC-VBR option is grayed out. How come? Am I doing something wrong?

How can I use the AAC-VBR encoder of QT7?

Reply #1
First export as QT movie and then convert to mpeg4 to pass-through, and then change the file ending to .m4a

I think it's best to wait for iTunes 4.8 

How can I use the AAC-VBR encoder of QT7?

Reply #2
Quote
First export as QT movie and then convert to mpeg4 to pass-through, and then change the file ending to .m4a

I think it's best to wait for iTunes 4.8 
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Actually, I did that at some point and selected the Variable Bit rate option from the
audio settings but when I played this track back in iTunes it reported it as a 96 Kbps
track and not one with some intermediate bitrate like it does with Nero AAC VBR
tracks. Is this really a VBR audio file? And why is it that the AAC-VBR option in the
MPEG-4 exporter is always disabled? I also have the AAChoo utility which can access
any QT MPEG-4 settings but with this option always disabled the problem remains.

And on another subject, why do I get two "Help" menu items on the menu bar
of QT7 every time I run it?

How can I use the AAC-VBR encoder of QT7?

Reply #3
It's just iTunes that doesn't report it as vbr. If you open it in QT, you'll see the actual bit-rate.

How can I use the AAC-VBR encoder of QT7?

Reply #4
Quote
It's just iTunes that doesn't report it as vbr. If you open it in QT, you'll see the actual bit-rate.
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Thanks! I'll try that. Do you also see two "Help" menus on the menu bar when
running QT7 ?

How can I use the AAC-VBR encoder of QT7?

Reply #5
Quote
It's just iTunes that doesn't report it as vbr. If you open it in QT, you'll see the actual bit-rate.
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Hmm.. I am not convinced that the encoded file is using the VBR encoder.
During the exporting to MPEG-4 using passthrough for the audio, QT reports
the audio track as AAC-LC and not AAC-VBR. And then when I play the
track with QT it reports the bitrate as 96.22 Kbps although I selected the
96-112 VBR option. Something is wrong with QT7. I am not sure the AAC-VBR
encoder is indeed enabled.

How can I use the AAC-VBR encoder of QT7?

Reply #6
The VBR encoder works fine. I've posted other samples, if you take a look at the uploads section.

How can I use the AAC-VBR encoder of QT7?

Reply #7
The file is effectively AAC-LC (that's the name of the AAC profile) even if it is VBR

AFAIK if it was CBR the bitrate would be exactly 96, not 96.22 Kbps. Try with a track a bit more difficult to encode if you want to see more difference.

How can I use the AAC-VBR encoder of QT7?

Reply #8
Quote
I think it's best to wait for iTunes 4.8 
I've been trying, but I sure am getting TIRED of waiting!!

How can I use the AAC-VBR encoder of QT7?

Reply #9
I used Cleaner in order to perform a batch encoding of audio files using the AAC VBR encoder. I am still not sure that a VBR algorithm is employed. I checked the reported bitrate using iTunes, QuickTime, VLC and on all audio files it is reported as something like 128.22 Kbps when using the 128-160 VBR setting. Is this encoder truly a VBR encoder, as for example the Nero AAC encoder, or is it some variation of the constant bitrate one which allows for some small variation in bitrate if required but with higher constraints e.g. more like an Average Bitrate algorithm would do?

How can I use the AAC-VBR encoder of QT7?

Reply #10
Quote
I am still not sure that a VBR algorithm is employed.


I've done a few test encodes and it is VBR. Fatboy.wav is a good example of a file where the bitrate will be in the higher range.

How can I use the AAC-VBR encoder of QT7?

Reply #11
Well, iTunes 4.8 is out, but there's nill sign of vbr encoding. It doesn't even report the actual bitrate on files encoded in QT7 

Better wait for iTunes 5 then

How can I use the AAC-VBR encoder of QT7?

Reply #12
QT7 for Windows wasn't included so obviously there is no VBR. Maybe they will update iTunes when QT7 is released? Doubt it, but maybe.

More waiting...yay

How can I use the AAC-VBR encoder of QT7?

Reply #13
I have QT 7 Pro installed on my system. I can make vbr files (really good ones actually) through QT but not through iTunes. Irksome . . .

How can I use the AAC-VBR encoder of QT7?

Reply #14
Quote
QT7 for Windows wasn't included so obviously there is no VBR. Maybe they will update iTunes when QT7 is released? Doubt it, but maybe.

More waiting...yay
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Actually that makes sense...but I think they might have to release a new iPod firmware package at that time as well, which could explain why they're dragging their feet.  Also, what would happen to all the music in the iTunes Music Store if CBR AAC suddenly wasn't Apple's favorite lossy codec?  Would they re-encode everything in the higher quality VBR setting or continue offering CBR files despite the existence of better encoding technology (like most if not all of the WMA services have done AFAIK)?

How can I use the AAC-VBR encoder of QT7?

Reply #15
Apple currently offers AAC @ 128 kbps. The record labels allow you to sell files up to 192 kbps. (some guy from Real Networks stated this some time ago) So at least I can't see any reason for them to start using higher bitrate vbr because they haven't yet even offered the best quality allowed.

How can I use the AAC-VBR encoder of QT7?

Reply #16
Huh? Labels place a limit on the quality others can sell? WTF? Why should they care?

Hmm... Sorry, off-topic.

How can I use the AAC-VBR encoder of QT7?

Reply #17
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...The record labels allow you to sell files up to 192 kbps. (some guy from Real Networks stated this some time ago)
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This can't be true.  [a href="http://www.buymusic.com/]BuyMusic.com[/url] has been selling WMA tracks at 256kbps for over a year now.

How can I use the AAC-VBR encoder of QT7?

Reply #18
Quote
Also, what would happen to all the music in the iTunes Music Store if CBR AAC suddenly wasn't Apple's favorite lossy codec?  Would they re-encode everything in the higher quality VBR setting or continue offering CBR files despite the existence of better encoding technology
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It's disappointing that VBR wasn't featured in iTunes 4.8, but it seems the regular encoder has been tuned as well.

Over time, they might switch over to VBR on the store, but it is probably some time off. Perhaps with iTunes 5?

How can I use the AAC-VBR encoder of QT7?

Reply #19
What makes you think the encoder was tuned?

How can I use the AAC-VBR encoder of QT7?

Reply #20
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What makes you think the encoder was tuned?
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Only in QT 7 of course. Not if you update to 4.8 while keeping QT 6.5.2

How can I use the AAC-VBR encoder of QT7?

Reply #21
Quote
Only in QT 7 of course. Not if you update to 4.8 while keeping QT 6.5.2
So they didn't upgrade the AAC encoder at ALL in iTunes 4.8?  What the heck are they waiting for? 

How can I use the AAC-VBR encoder of QT7?

Reply #22
Quote
Quote
Only in QT 7 of course. Not if you update to 4.8 while keeping QT 6.5.2
So they didn't upgrade the AAC encoder at ALL in iTunes 4.8?  What the heck are they waiting for? 
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It uses QuickTime for encoding, so you have to wait for the Windows version of QT7. 

How can I use the AAC-VBR encoder of QT7?

Reply #23
I have succesfully encoded some VBR files using QT7 on my mac.  As stated above it is not yet enabled for mp4 export.  You have to export a QT movie (.mov) and there are five VBR settings to choose from.  Then to play it on an ipod export into an mp4 container using passthrough on the audio (otherwise it will re-encode).

I wrote an applescript to automate this and thought I was very clever.  Then I found that the files are not really VBR!  Manually encoded files are true VBR, but not the applescript ones.

This implies that scripting is not fully implemented for this audio codec yet.  This may explain why it is not available for iTunes yet.

The bottom line is that it is not ready for prime time yet.  I think I will wait for a later release of QT (and hopefully iTunes support) before testing it.

How can I use the AAC-VBR encoder of QT7?

Reply #24
Quote
I have succesfully encoded some VBR files using QT7 on my mac.  As stated above it is not yet enabled for mp4 export.  You have to export a QT movie (.mov) and there are five VBR settings to choose from.  Then to play it on an ipod export into an mp4 container using passthrough on the audio (otherwise it will re-encode).

I wrote an applescript to automate this and thought I was very clever.  Then I found that the files are not really VBR!  Manually encoded files are true VBR, but not the applescript ones.

This implies that scripting is not fully implemented for this audio codec yet.  This may explain why it is not available for iTunes yet.

The bottom line is that it is not ready for prime time yet.  I think I will wait for a later release of QT (and hopefully iTunes support) before testing it.
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That's odd. Could you post the applescript?