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Topic: Core Audio/QuickTime True VBR vs. Nero AAC (Read 95193 times) previous topic - next topic
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Core Audio/QuickTime True VBR vs. Nero AAC

Reply #76 –
Hello. I have 2 questions to make regarding this topic.

Does the nero encoder have true VBR or it's only QT that has this possibility? And if it doesn't is it expected to have true VBR in the new version that's coming soon?

And the 2nd question is: I have the QT pro installed on Windows. I followed the process you described and in the end I got an MPEG-4 Movie file. While encoding with Itunes gives me an MPEG-4 Audio file. Does XLD for example produce a video or an audio file? I think that probably this is not important at all but I am curious to know whether it should be like this or I did something wrong..

Core Audio/QuickTime True VBR vs. Nero AAC

Reply #77 –
  • I am under the impression that Nero's encoder is true VBR.  However, from what I remember, each frame is not independent of the other.  I could be wrong on this as past discussions are in my fuzzy memory bank right now.  My own personal observation is that the Nero AAC encoder is able to fluctuate its bitrate more than the VBR constrained setting in QuickTime/iTunes.
  • XLD will produce audio files.  Technically speaking, on Windows, QuickTime Pro is producing mpeg-4 files containing AAC audio.  They aren't necessarily video files as they don't contain an video portion.  You follow the same procedure as when making video files.  All you have to do is rename them from *.mp4 to *.m4a and you will be set.

Core Audio/QuickTime True VBR vs. Nero AAC

Reply #78 –
I have been convinced in the thread that we both don't remember exactly, that Nero's VBR implementation is as "true" as Quicktime's.

Core Audio/QuickTime True VBR vs. Nero AAC

Reply #79 –
Quote from: kornchild2002 on
I am under the impression that Nero's encoder is true VBR.  However, from what I remember, each frame is not independent of the other.  I could be wrong on this as past discussions are in my fuzzy memory bank right now.  My own personal observation is that the Nero AAC encoder is able to fluctuate its bitrate more than the VBR constrained setting in QuickTime/iTunes.

about your first point, I was always under the impression that True VBR was a term that could only be applied to an encoder that was both quality-based and completely frame-independent (meaning Nero's VBR setting can't be considered "True" VBR)... though I'm always willing to learn something new if one of the developers or someone who knows more about this could clarify this or provide any input.

and about the second point, I've observed that Nero and Quicktime seem to perform very similarly in points of lesser complexity (i.e. during quieter points in a song), but in most songs that build to a peak/become very complex, it seems like Nero pushes itself up to a certain bitrate and remains there (or at least within +/- 5kbps) until the dynamic of the song backs off, while for these same songs, QuickTime still continues to show a substantial amount of variation in bitrate... similar to you, though, these are just my own personal observations, and I'm sure that a difference in the kinds of music in our libraries could have something to do with it.
Archive- FLAC (-v 8)
Portable- QuickTime AAC (True VBR/-q 77)

Core Audio/QuickTime True VBR vs. Nero AAC

Reply #80 –
New Nero is out,did anyone make any test to see how it compares to the latest true vbr AAC by Apple?
 

Core Audio/QuickTime True VBR vs. Nero AAC

Reply #81 –
So I just discovered this thread after I found some surprising results.

I'm transcoding my collection to 64kbps he-aac to play back on my mobile, which usually plays back music in noisy environments so transparency isn't paramount.

So i used my mac, encoded using coreaudio a song using these options "64kbps/maximum quality/vbr" which is True VBR, then i used the latest Nero and set target quality at .26 (67kbps)

Here's the surprising results.

apple aac 64kbps setting, max quality, true vbr =  66kbps 2.98mb (foobar2000 file properties)
nero quality .26 = 75kbps @ 2.61mb, so to get nero to around apple's filesize, i increased the quality to .30 and achieved a 88kbps file at 2.92mb.

Really? Why are apple's songs so much bigger for a less average bitrate reported by foobar2000?

I changed the VBR refresh rate in fb2k to 6 times per second and apple's VBR is EVERYWHERE. here's my unscientific view while looking for the lowest/highest bitrates reported in fb2k for the first 60 seconds of the song. i'm comparing nero .30 vs apple because the file sizes are close.

nero .30 = 71kbps low, 98kbps high
apple  =  51kbps low, 107kbps high


We're definitely dealing with two totally different algorithms here

edit, updated the apple highest bitrate when i watched the songs again.

Core Audio/QuickTime True VBR vs. Nero AAC

Reply #82 –
Does iTunes 10 bring an improved AAC?

Core Audio/QuickTime True VBR vs. Nero AAC

Reply #83 –
No,it's still the same old quicktime behind. A new quicktime update should be expected with Mac OS X 10.6.5 but we don't know if it's going to update also AAC encoding.