[MEncoder-users] Re: Re: Tutorial?

[The Wanderer]

Jeff Clagg wrote:

> On Fri, Oct 06, 2006 at 10:55:40PM +0000, Ilya Zakharevich wrote:

(Please, do not omit attributions when quoting.)

>>> In a nutshell, when you specify pass=1, xvid ignores any option
>>> setting either bitrate or quantizer. But, so what?
>> 
>> So that I can change my mind, and specify different bitrate on
>> pass=2 command line.
> 
> Huh? I'm not even sure what you're trying to say here. I suspect your
> statement is based on a misunderstanding.

I suspect that what he meant is "so that I can realize that it is safe
to specify a different bitrate in pass 2 if I happen to change my mind
after starting the first pass", or something along those lines.

>>> As for exactly what turbo changes, it makes the pass faster, and
>>> that's all most users want to know.
>> 
>> Please do not vouch for "most users".  Thanks.
> 
> It's true, whether you agree or not. Unless you presume to vouch for
> most users, yourself.

I think that you both mean "speak for". To "vouch for" somone is to
confirm their credentials, as it were - to indicate that they are, in
fact, trustworthy.

>>> How is it unclear?
>> 
>> Could you please explain WHICH of two answers is "clear", and how
>> one can deduce it looking in documentation.  I do not know even
>> after running half a dozen of tests.
> 
> As the docs say, positive number sets target bitrate, negative number
> sets target output file size (which is the same as setting bitrate,
> only you make the computer do slightly more arithmetic for you). I
> probably shouldn't have to say this, but if you have pass=1 in your
> xvidencopts, you will not observe any difference.

However, his question appears to be whether it is "instantaneous
bitrate" (i.e., the bitrate which will be used at all times no matter
what) or "average bitrate" (i.e., the total number of bits in the stream
divided by the total length of the stream). The latter is what is meant
in all cases, but the only way to know this from the man page is to
realize that A: the former implies CBR and B: CBR is not default. I
don't think that this is an overly high bar, but he may disagree.

-- 
       The Wanderer

Warning: Simply because I argue an issue does not mean I agree with any
side of it.

Secrecy is the beginning of tyranny.