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Topic: aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best? (Read 5815 times) previous topic - next topic

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  • Anakunda
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aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best?
HI!! 
As you know there's published new oggenc and libvorbis Lancer builds based on aoTuV b6.03. So regarding it's writing library they should use the same code, however looking closer on the result the Lancer builds give slightly different output:

Comparing:
"C:\Users\Anakunda\AppData\Local\Temp\aoTuVb6.03.ogg"
"C:\Users\Anakunda\AppData\Local\Temp\Lancer.ogg"
Differences found: 1179627 sample(s), starting at 0.4542404 second(s), peak: 0.1180483 at 30.8317687 second(s), 2ch

So obviously I'm interested where's the difference and which builds are expected to give more transparent output. Thanks!

aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best?
Reply #1
This looks interesting. Can you hear any difference? I will try them both out soon since I use the Lance build. Regards.

  • Anakunda
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aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best?
Reply #2
I don't hear any difference since both transcodes sound subjective transparent but anyway interested if Lancer build contains any additional tweaks to psycho-acoustic routines 

  • kode54
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  • Administrator
aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best?
Reply #3
The results of encoding lossy formats, usually when there's floating point math involved, can vary by what compiler was used to produce the binaries.

  • Anakunda
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aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best?
Reply #4
What about /Qprec-div- ?

  • john33
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  • Developer
aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best?
Reply #5
The speed up in the 'Lancer' builds is directly as a consequence of replacing the standard code with highly optimized 'hand-rolled' SSE/SSE2 specific code. It is not simply the use of a different set of compiler options. Two particular routines that are heavily modified are 'psy.c' (increases from 2211 lines of code to 5178) and 'smallft.c' (increases from 1256 lines of code to 6832). Output differences are, therefore, to be expected although no one has suggested they are audible (except in a particular instance referred to elsewhere).

I don't recall hearing tests having been conducted, but I also don't recall anyone claiming to hear any differences (save for the instance already mentioned).
John
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My compiles and utilities are at http://www.rarewares.org/

  • Clifoo
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aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best?
Reply #6
As john33 said (and according to this Wiki page) the difference in stream between aoTuV and corresponding Lancer build is cosmetic, and nobody should be able to spot it.  However, the newest Lancer build is from 2006 (based on aoTuV b5) and you are comparing it to b6. Between b5 and b6, there've been some optimalisations to low bitrates, and aoTuV is bound to perform slightly better.

  • Anakunda
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aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best?
Reply #7
I thnk it s not  The newest Lancer build from 2012 is told to be based on aoTuV beta 6.3

  • Clifoo
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aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best?
Reply #8
Well good news then, I've only been aware to this 'official' page and didn't read your post carefully. Where did you find it?
  • Last Edit: 14 July, 2012, 09:35:06 AM by Clifoo

  • john33
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  • Developer
aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best?
Reply #9
The Lancer builds currently on offer at Rarewares and here are based on aoTuVb6.03. These are not the original 'Blacksword' Lancer builds. Code modifications were ported from 5.7 version (if I recall correctly).
John
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My compiles and utilities are at http://www.rarewares.org/

  • kode54
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  • Administrator
aoTuV b6.03 oggenc+libvorbis slightly diff outputs; why/which is best?
Reply #10
Sorry about that, I wasn't aware this was an optimized encoder. Yeah, hand optimizing the math will change the output as well, but it's not likely to be audible.