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Topic: aac 5.1 bitrate (Read 2799 times) previous topic - next topic

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  • grokwik
  • [*]
aac 5.1 bitrate
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 ??? 

ex : 176kbps=2*70+35+1
WavPack 4.31 -hm

  • kurtnoise
  • [*][*][*][*]
aac 5.1 bitrate
Reply #1
Quote
Do I make a mistake in my computation ??? 

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


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


edit : and the formula applies more to a codec with a cbr mode. Well...it's just an assumption. maybe i'm wrong.
  • Last Edit: 20 October, 2004, 03:26:24 PM by kurtnoise

  • grokwik
  • [*]
aac 5.1 bitrate
Reply #2
thanks kurtnoise for your answer !
In fact the ac3 track is from star wars episode IV (la guerre des ├ętoiles quoi)
WavPack 4.31 -hm