[MPlayer-dev-eng] Announce of Movieconvert

[Diego Biurrun]

nix.wie.weg at gmx.de writes:
> 
> Diego Biurrun wrote:
> 
> >You are mixing up options, suboptions/parameters and filters.
> >
> >  -vf scale_w=width,scale_h=height,sws=1
> >
> >would build up a filter chain, calling first the "scale_w" filter with
> >"width" as parameter, then the "scale_h" filter with height as
> >parameter and finally the sws filter with "1" as parameter.  Thus
> >
> >  -vf crop_w=width,crop_h=height,crop_x=x,crop_y=y
> >
> >would call four filters with one argument, while
> >
> >  -vf crop=width:height:x:y
> >
> >calls one filter with four arguments.
> >
> Ok maybe I was not clear enough:
> First we define everything starting with an "-" is an option and can 
> have suboptions and second we have filter. So my problems still remain:
> 
> 1. Why are such things like -sws or -ofps options? They should be 
> suboptions.

Feel free to send a patch ;-)

> 2. Why are filter seperated by ",", while suboptions are seperated by ":"

If you'd have a close look at the VIDEO FILTER section of the man page
again, you will see that filters have parameters (suboptions if you
will) that do get separated by ",".

> 3. You maybe right with your argument, that my written filter syntax 
> would call 4 different filter, but that wasn't the point. Maybe the 
> Syntax should be more like this -vf 
> crop_w=width:crop_h=height:crop_x=x:crop_y=y;scale_w=width:scale_h=height;...  
> (note the ";" between crop and scale options)
> The advantage is simply that the second syntax can be generated, while 
> the syntax which is used now can not, which means you have to write one 
> function (or one if clause) per filter/option/suboption ...

Some filters support named parameters, just not all do.  From the
manual page:

  With filters that support it, you can access parameters by their
  name.

  -vf <filter>=help
    Prints the parameter names and parameter value ranges for a par-
    ticular filter.

  -vf <filter=named_parameter1=value1[:named_parameter2=value2:...]>
    Sets a named parameter to the given value.  Use on and off or yes
    and no to set flag parameters.

Isn't that precisely what you have in mind?

Diego