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

[Nico Sabbi]

Alain Barthélemy wrote:

>Le lundi 31 mai 2004, 16:11:22 ou environ The Wanderer <inverseparadox at comcast.net> a écrit:
>  
>
>>Alain Barthélemy wrote:
>>
>>    
>>
>>>Let's have an example. I do a lot of encoding of TV signal. TV signal
>>>is never of optimum quality of course. Here is my instruction line:
>>>
>>>mencoder -tv driver=v4l:width=640:height=480:amode=0 -ovc lavc 
>>>-lavcopts vcodec=mpeg4:vbitrate=1800:mbd=2:acodec=mp3:v4mv -oac 
>>>mp3lame -lameopts cbr:br=96:mode=3 -vf crop=620:460,pp=tn/lb,scale 
>>>-zoom -xy 640 -sws 1 tv:// -o movie.avi -endpos <sec>
>>>
>>>I am not original. I just try what I read on the list.
>>>      
>>>
>>Any particular reason you don't use -oac lavc -lavcopts
>>acodec=mp3:abitrate=96:... ? Do you just really need mono sound?
>>
>>-- 
>>      The Wanderer
>>    
>>
>
>What does abitrate=96 do here? If I read the manpage, I see: 
>
>abitrate = <value>
>    Audio bitrate in kBit (default 224)
>
>What does it do with mono/stereo sound and there is always a default value (224).
>
>Why 224 as default? Why not 128 as default?
>
>  
>

because the default codec is mp2 (which compresses much less and worse), 
not mp3