On Sun, 2003-07-27 at 15:58, Dominik Kuhlen wrote:> 1 why is it called oggenc? (vorbisenc would make more sense)
No idea. oggenc was shorter probably. :) We've talked about this
issue, but haven't reached a consensus beyond "leave it unless we have
a
compelling reason to switch".
> 2 Is it true, that oggenc uses only some predefined codebooks (depending on
-q)?
Yes, they are predefined. (Keep in mind most of the answers here apply
to the reference vorbis encoding libraries, which nearly every tool
uses.)
> 2.1 Are they just "random" books, or were they
"optimized" in any way
They are optimized, though this is somewhat of a black art.
> 2.2 Is it possible, that some codebooks are stored in the header, but are
never used (even in long (>3min) files)?
I don't think so, but I don't know the answer for this one for sure.
<p>> 4 Are there any docs about the psychoacoustic model?
The specs here:
http://www.xiph.org/ogg/vorbis/docs.html
mainly regard decoding. I don't know of any precise documentation of
the psych model used.
> 5 Does it compress using two passes (whole file)?
No.
> 5.1 Is it necessary to use twopass to do "real" VBR (1. pass:
estimate BR; 2.pass: compress)?
> (ups, this is a general question about VBR)
> 5.2 Same applies to windowsizes: It has to check the file before choosing
optimal windowsizes
Because of the previous answer, these are also no. The standard
encoding libraries do single pass VBR.
---
Stan Seibert
<p><p>--- >8 ----
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