[MPlayer-users] needing YUY2 -> YV12 output filter

[DEBERT Jean-Louis]

D Richard Felker III wrote:

>  [Automatic answer: RTFM (read DOCS, FAQ), also read 
>  DOCS/bugreports.html]
>  On Thu, Nov 28, 2002 at 07:40:13AM +0100, DEBERT Jean-Louis wrote:
>  > [Automatic answer: RTFM (read DOCS, FAQ), also read 
>  DOCS/bugreports.html]
>  > 
>  > Hi,
>  > 
>  > Now to my question: is there any output filter to convert
>  > YUY2 (which is the output format from the quicktime dll,
>  > seeing from the codecs.conf file) to YV12 ???
>  > The idea would be to combine this with the existing lavc
>  > filter in order to be able to output all those .mov files
>  > on the big TV screen through the tv-out on my dxr3 card
>  > (as well as possible other formats with YUY2-only output).
>  
>  -vop scale
>  
>  Rich

Okay, this works ... Thanks.
... although IMHO it is not so obvious _why_ it works: the vop.txt
file only says it does YUV <-> RGB conversion so it's not obvious
(without going into the source code, provided one can understand it)
that it can do other types of conversion too. Perhaps it could be
expanded in the vop.txt file ?

Another thing that's not obvious to me is why _sometimes_,
with the very same command line:  
    #  mplayer -vo dxr3 -vop lavc some_file.mov -v
sometimes, I say, the scale filter is invoked _automatically_,
without having to specify it explicitly. What baffles me is not
that it does, its that it doesn't always do it (and I can't 
see a pattern to it). When it does _not_ invoke scale
automatically, I get the usual message:
"Can't find codec matching selected -vo and video format 0x33515653!"
and no video at all on the tv output. 
Any idea ?