[MPlayer-users] Two-passes encoding - What happens exactly?

[The Wanderer]

Alain Barthélemy wrote:

> Le Tuesday 01 June 2004, 04:32:23 ou environ The Wanderer
> <inverseparadox at comcast.net> a écrit:
> 
>> Fabio S. wrote:
>> 
>>> It is the same for me: it would be nice if somebody would explain
>>> exactly (in a qualitative way) what happens during two pass
>>> encoding, how to use it for (as you said: do we need to rewrite
>>> all options?) and when we can use it (is it possible to use it
>>> for capturing from the tv?)
>> 
>> Well, I'm not sure I quite understand what you're asking in the
>> first of those three cases, but I can take a shot at the others.
>> 
>> Yes, you need to use all of the same options on both passes; there
>> are apparently a few which you can vary slightly without hurting
>> anything, but for the most part changing the options between passes
>> will mess things up.
> 
> My question was not to know if we could change options between two
> passes but if we had to keep the same options between the first
> original TV-signal encoding and the two passes. You answered it at
> your first reply. The -lavcopts options had to be retyped.

...I don't know if I quite follow this. Do you mean that you're encoding
with libavcodec from TV, and then using two-pass mode on the result?

That's not as good as encoding to something lossless from TV and then
using two-pass mode on the result, but it will work. However, it is
*not* necessary to keep the same options between the initial from-TV
encoding and the two-pass encoding; it is only necessary to keep all of
the same options between the two passes.

-- 
       The Wanderer

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

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