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aac 5.1 bitrate
grokwik
post Oct 20 2004, 07:57
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I searched through the forum and found that formula to compute the bitrate for 5.1 files :

bit rate = 2 x stereo bit rate for same quality + 1 mono bit rate for same q + X, where X is only few kb/s for LFE...

I have encoded ac3 files to 5.1 aac using oagmachine and lastest nero dlls using vbr he aac (50 - 70 kbps) profile.

With this profile i expect a 125 to 175 kbps file (which I know is poor quality..)

but my file is around 230 kbps (which is enoug quality i think) which would correspond to a 92 kbps profile in nero encoder.

Do I make a mistake in my computation ??? huh.gif

ex : 176kbps=2*70+35+1


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kurtnoise
post Oct 20 2004, 20:20
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QUOTE (grokwik @ Oct 20 2004, 07:57 AM)
Do I make a mistake in my computation ???  huh.gif

I don't think so...This is simply the beauty of VBR biggrin.gif


In fact, the bitrate depends on many things : the kind of source, the "style" too (concert, movie, etc...). cool.gif


edit : and the formula applies more to a codec with a cbr mode. Well...it's just an assumption. maybe i'm wrong. unsure.gif

This post has been edited by kurtnoise: Oct 20 2004, 20:26


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http://www.unite-video.com/phpbb/viewtopic.php?t=5412 :: An overview of all lossless Audio Formats (in french language ;-)
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grokwik
post Oct 21 2004, 21:35
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thanks kurtnoise for your answer !
In fact the ac3 track is from star wars episode IV (la guerre des étoiles quoi)


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