[Mplayer-advusers] trouble with the -vm option

[Arpi]

Hi,

> > there are 2 levels of aspect correction: prescaling (-aspect, doen before
> > applying filters) and display aspect (-monitoraspect, done in libvo drivers
> > where it has any sense)
> > 
> > -aspect has effect on filters, even on scale, but scale has option to use
> > original w/h or prescaled (aspect corrected) w/h
> > this is the difference between 0/-1 and 2/3
> 
> well, it would be nice if monitoraspect would be used in the scale plugin
> when zoom isn't selected. right now i have a fixed aspect in my config and
> have to play when a movie isn't 4:3.

imho it's bad, very bad idea:
- it's on -vo drivers how to handle monitoraspect, more over, coming from
current mplayer architecture, teh video filter layer cannot even access this
info
- encoding files to the aspect ratio for _your_ monitor is a bad idea, think
if someone with different monitor wants to playback it... also think if
_you_ want to playback it, then the monitoraspect value will be applied
_twice_

> btw, the manpage mentions -1 for scale to use the aspect ratio of the movie,
> but actually it is -3 for movie aspect, -2 for monitor resolution aspect
> (without using -monitoraspect).

huh?

    if(vf->priv->w==-3) vf->priv->w=vf->priv->h*width/height; else
    if(vf->priv->w==-2) vf->priv->w=vf->priv->h*d_width/d_height;
    if(vf->priv->w<0) vf->priv->w=width; else
    if(vf->priv->w==0) vf->priv->w=d_width;

so:
-1 -> use original (without prescaling ie without -aspect) w/h
 0 -> use prescaled (-aspect value applied) w/h
-2 -> calculate w from h using prescaled aspect (-aspect applied)
-3 -> calculate w from h using original aspect (-aspect ignored)

note that -monitoraspect is always ignored at vidoe codec/filter layer.
it's, as its name says, is for video out to correct square pixels to
monitor's pixel aspect. no sense and no way of calculating -monitoraspect
into -vop scale.


A'rpi / Astral & ESP-team

--
Developer of MPlayer, the Movie Player for Linux - http://www.MPlayerHQ.hu